Merge 57af702500 into a15dd75d98

* Update mypy to 1.6.1

* Fix mypy "Source file found twice under different module names" error

* Ignore type of intialized abstract class in tests

* Use more specific type ignore method-assign

* Type ignore for message.get_all

* Remove unused type ignore

* Add SizedBuffer type for xmlrpc.client.Transport subclass

* Add Self type for RequestHandlerClass in test

* Add type ignore for shutil.rmtree onexc handler

* Quote SizedBuffer

* Add news entry

* Remove no longer correct comment

* Update self import

* Also ignore type onerror=handler

* Update news entry

* Update news entry

.pre-commit-config.yaml

@@ -22,25 +22,26 @@ repos:
   - id: black
 
 - repo: https://github.com/astral-sh/ruff-pre-commit
-  rev: v0.0.292
+  rev: v0.1.4
   hooks:
     - id: ruff
+      args: [--fix, --exit-non-zero-on-fix]
 
 - repo: https://github.com/pre-commit/mirrors-mypy
-  rev: v0.961
+  rev: v1.6.1
   hooks:
   - id: mypy
     exclude: tests/data
     args: ["--pretty", "--show-error-codes"]
     additional_dependencies: [
-        'keyring==23.0.1',
-        'nox==2021.6.12',
+        'keyring==24.2.0',
+        'nox==2023.4.22',
         'pytest',
-        'types-docutils==0.18.3',
-        'types-setuptools==57.4.14',
-        'types-freezegun==1.1.9',
-        'types-six==1.16.15',
-        'types-pyyaml==6.0.12.2',
+        'types-docutils==0.20.0.3',
+        'types-setuptools==68.2.0.0',
+        'types-freezegun==1.1.10',
+        'types-six==1.16.21.9',
+        'types-pyyaml==6.0.12.12',
     ]
 
 - repo: https://github.com/pre-commit/pygrep-hooks

docs/html/cli/pip_install.rst

@@ -45,8 +45,8 @@ When looking at the items to be installed, pip checks what type of item
 each is, in the following order:
 
 1. Project or archive URL.
-2. Local directory (which must contain a ``setup.py``, or pip will report
-   an error).
+2. Local directory (which must contain a ``pyproject.toml`` or ``setup.py``,
+   otherwise pip will report an error).
 3. Local file (a sdist or wheel format archive, following the naming
    conventions for those formats).
 4. A requirement, as specified in :pep:`440`.

docs/html/reference/build-system/pyproject-toml.md

@@ -130,6 +130,13 @@ dealing with [the same challenges as pip has for legacy builds](build-output).
 
 ## Fallback Behaviour
 
+```{warning}
+The following snippet merely describes the fallback behavior. For valid
+examples of `pyproject.toml` to use with setuptools, please refer to
+[the setuptools documentation](
+https://setuptools.pypa.io/en/stable/userguide/quickstart.html#basic-use).
+```
+
 If a project does not have a `pyproject.toml` file containing a `build-system`
 section, it will be assumed to have the following backend settings:
 

docs/html/topics/configuration.md

@@ -19,8 +19,8 @@ and how they are related to pip's various command line options.
 
 ## Configuration Files
 
-Configuration files can change the default values for command line option.
-They are written using a standard INI style configuration files.
+Configuration files can change the default values for command line options.
+The files are written using standard INI format.
 
 pip has 3 "levels" of configuration files:
 
@@ -28,11 +28,15 @@ pip has 3 "levels" of configuration files:
 - `user`: per-user configuration file.
 - `site`: per-environment configuration file; i.e. per-virtualenv.
 
+Additionally, environment variables can be specified which will override any of the above.
+
 ### Location
 
 pip's configuration files are located in fairly standard locations. This
 location is different on different operating systems, and has some additional
-complexity for backwards compatibility reasons.
+complexity for backwards compatibility reasons. Note that if user config files
+exist in both the legacy and current locations, values in the current file
+will override values in the legacy file.
 
 ```{tab} Unix
 
@@ -88,9 +92,10 @@ Site
 ### `PIP_CONFIG_FILE`
 
 Additionally, the environment variable `PIP_CONFIG_FILE` can be used to specify
-a configuration file that's loaded first, and whose values are overridden by
-the values set in the aforementioned files. Setting this to {any}`os.devnull`
-disables the loading of _all_ configuration files.
+a configuration file that's loaded last, and whose values override the values
+set in the aforementioned files. Setting this to {any}`os.devnull`
+disables the loading of _all_ configuration files. Note that if a file exists
+at the location that this is set to, the user config file will not be loaded.
 
 (config-precedence)=
 
@@ -99,10 +104,10 @@ disables the loading of _all_ configuration files.
 When multiple configuration files are found, pip combines them in the following
 order:
 
-- `PIP_CONFIG_FILE`, if given.
 - Global
 - User
 - Site
+- `PIP_CONFIG_FILE`, if given.
 
 Each file read overrides any values read from previous files, so if the
 global timeout is specified in both the global file and the per-user file

docs/pip_sphinxext.py

@@ -194,22 +194,17 @@ class PipReqFileOptionsReference(PipOptions):
             opt = option()
             opt_name = opt._long_opts[0]
             if opt._short_opts:
-                short_opt_name = "{}, ".format(opt._short_opts[0])
+                short_opt_name = f"{opt._short_opts[0]}, "
             else:
                 short_opt_name = ""
 
             if option in cmdoptions.general_group["options"]:
                 prefix = ""
             else:
-                prefix = "{}_".format(self.determine_opt_prefix(opt_name))
+                prefix = f"{self.determine_opt_prefix(opt_name)}_"
 
             self.view_list.append(
-                "*  :ref:`{short}{long}<{prefix}{opt_name}>`".format(
-                    short=short_opt_name,
-                    long=opt_name,
-                    prefix=prefix,
-                    opt_name=opt_name,
-                ),
+                f"*  :ref:`{short_opt_name}{opt_name}<{prefix}{opt_name}>`",
                 "\n",
             )
 

news/11815.doc.rst

@@ -0,0 +1 @@
+Fix explanation of how PIP_CONFIG_FILE works

news/12122.doc.rst

@@ -0,0 +1,3 @@
+Add a warning explaining that the snippet in "Fallback behavior" is not a valid
+``pyproject.toml`` snippet for projects, and link to setuptools documentation
+instead.

news/12389.bugfix.rst

@@ -0,0 +1 @@
+Update mypy to 1.6.1 and fix/ignore types

news/12390.trivial.rst

@@ -0,0 +1 @@
+Update ruff versions and config for dev

news/12393.trivial.rst

@@ -0,0 +1 @@
+Enforce and update code to use f-strings via Ruff rule UP032

news/12417.doc.rst

@@ -0,0 +1 @@
+Fix outdated pip install argument description in documentation.

news/370392cf-52cd-402c-b402-06d2ff398f89.bugfix.rst

@@ -0,0 +1 @@
+Fix mercurial revision "parse error": use ``--rev={ref}`` instead of ``-r={ref}``

pyproject.toml

@@ -84,8 +84,8 @@ ignore = [
     "B020",
     "B904", # Ruff enables opinionated warnings by default
     "B905", # Ruff enables opinionated warnings by default
-    "G202",
 ]
+target-version = "py37"
 line-length = 88
 select = [
     "ASYNC",
@@ -102,6 +102,7 @@ select = [
     "PLR0",
     "W",
     "RUF100",
+    "UP032",
 ]
 
 [tool.ruff.isort]

setup.py

@@ -77,7 +77,7 @@ setup(
     entry_points={
         "console_scripts": [
             "pip=pip._internal.cli.main:main",
-            "pip{}=pip._internal.cli.main:main".format(sys.version_info[0]),
+            f"pip{sys.version_info[0]}=pip._internal.cli.main:main",
             "pip{}.{}=pip._internal.cli.main:main".format(*sys.version_info[:2]),
         ],
     },

src/pip/_internal/cli/cmdoptions.py

@@ -582,10 +582,7 @@ def _handle_python_version(
     """
     version_info, error_msg = _convert_python_version(value)
     if error_msg is not None:
-        msg = "invalid --python-version value: {!r}: {}".format(
-            value,
-            error_msg,
-        )
+        msg = f"invalid --python-version value: {value!r}: {error_msg}"
         raise_option_error(parser, option=option, msg=msg)
 
     parser.values.python_version = version_info
@@ -921,9 +918,9 @@ def _handle_merge_hash(
         algo, digest = value.split(":", 1)
     except ValueError:
         parser.error(
-            "Arguments to {} must be a hash name "
+            f"Arguments to {opt_str} must be a hash name "
             "followed by a value, like --hash=sha256:"
-            "abcde...".format(opt_str)
+            "abcde..."
         )
     if algo not in STRONG_HASHES:
         parser.error(

src/pip/_internal/cli/parser.py

@@ -229,9 +229,9 @@ class ConfigOptionParser(CustomOptionParser):
                     val = strtobool(val)
                 except ValueError:
                     self.error(
-                        "{} is not a valid value for {} option, "
+                        f"{val} is not a valid value for {key} option, "
                         "please specify a boolean value like yes/no, "
-                        "true/false or 1/0 instead.".format(val, key)
+                        "true/false or 1/0 instead."
                     )
             elif option.action == "count":
                 with suppress(ValueError):
@@ -240,10 +240,10 @@ class ConfigOptionParser(CustomOptionParser):
                     val = int(val)
                 if not isinstance(val, int) or val < 0:
                     self.error(
-                        "{} is not a valid value for {} option, "
+                        f"{val} is not a valid value for {key} option, "
                         "please instead specify either a non-negative integer "
                         "or a boolean value like yes/no or false/true "
-                        "which is equivalent to 1/0.".format(val, key)
+                        "which is equivalent to 1/0."
                     )
             elif option.action == "append":
                 val = val.split()

src/pip/_internal/commands/cache.py

@@ -175,7 +175,7 @@ class CacheCommand(Command):
             files += self._find_http_files(options)
         else:
             # Add the pattern to the log message
-            no_matching_msg += ' for pattern "{}"'.format(args[0])
+            no_matching_msg += f' for pattern "{args[0]}"'
 
         if not files:
             logger.warning(no_matching_msg)

src/pip/_internal/commands/configuration.py

@@ -242,17 +242,15 @@ class ConfigurationCommand(Command):
                 e.filename = editor
             raise
         except subprocess.CalledProcessError as e:
-            raise PipError(
-                "Editor Subprocess exited with exit code {}".format(e.returncode)
-            )
+            raise PipError(f"Editor Subprocess exited with exit code {e.returncode}")
 
     def _get_n_args(self, args: List[str], example: str, n: int) -> Any:
         """Helper to make sure the command got the right number of arguments"""
         if len(args) != n:
             msg = (
-                "Got unexpected number of arguments, expected {}. "
-                '(example: "{} config {}")'
-            ).format(n, get_prog(), example)
+                f"Got unexpected number of arguments, expected {n}. "
+                f'(example: "{get_prog()} config {example}")'
+            )
             raise PipError(msg)
 
         if n == 1:

src/pip/_internal/commands/debug.py

@@ -95,7 +95,7 @@ def show_actual_vendor_versions(vendor_txt_versions: Dict[str, str]) -> None:
         elif parse_version(actual_version) != parse_version(expected_version):
             extra_message = (
                 " (CONFLICT: vendor.txt suggests version should"
-                " be {})".format(expected_version)
+                f" be {expected_version})"
             )
         logger.info("%s==%s%s", module_name, actual_version, extra_message)
 
@@ -120,7 +120,7 @@ def show_tags(options: Values) -> None:
     if formatted_target:
         suffix = f" (target: {formatted_target})"
 
-    msg = "Compatible tags: {}{}".format(len(tags), suffix)
+    msg = f"Compatible tags: {len(tags)}{suffix}"
     logger.info(msg)
 
     if options.verbose < 1 and len(tags) > tag_limit:
@@ -134,9 +134,7 @@ def show_tags(options: Values) -> None:
             logger.info(str(tag))
 
         if tags_limited:
-            msg = (
-                "...\n[First {tag_limit} tags shown. Pass --verbose to show all.]"
-            ).format(tag_limit=tag_limit)
+            msg = f"...\n[First {tag_limit} tags shown. Pass --verbose to show all.]"
             logger.info(msg)
 
 

src/pip/_internal/commands/index.py

@@ -128,12 +128,12 @@ class IndexCommand(IndexGroupCommand):
 
             if not versions:
                 raise DistributionNotFound(
-                    "No matching distribution found for {}".format(query)
+                    f"No matching distribution found for {query}"
                 )
 
             formatted_versions = [str(ver) for ver in sorted(versions, reverse=True)]
             latest = formatted_versions[0]
 
-        write_output("{} ({})".format(query, latest))
+        write_output(f"{query} ({latest})")
         write_output("Available versions: {}".format(", ".join(formatted_versions)))
         print_dist_installation_info(query, latest)

src/pip/_internal/commands/install.py

@@ -607,12 +607,8 @@ class InstallCommand(RequirementCommand):
             version = package_set[project_name][0]
             for dependency in missing[project_name]:
                 message = (
-                    "{name} {version} requires {requirement}, "
+                    f"{project_name} {version} requires {dependency[1]}, "
                     "which is not installed."
-                ).format(
-                    name=project_name,
-                    version=version,
-                    requirement=dependency[1],
                 )
                 parts.append(message)
 

src/pip/_internal/configuration.py

@@ -59,8 +59,8 @@ def _disassemble_key(name: str) -> List[str]:
     if "." not in name:
         error_message = (
             "Key does not contain dot separated section and key. "
-            "Perhaps you wanted to use 'global.{}' instead?"
-        ).format(name)
+            f"Perhaps you wanted to use 'global.{name}' instead?"
+        )
         raise ConfigurationError(error_message)
     return name.split(".", 1)
 
@@ -327,33 +327,35 @@ class Configuration:
     def iter_config_files(self) -> Iterable[Tuple[Kind, List[str]]]:
         """Yields variant and configuration files associated with it.
 
-        This should be treated like items of a dictionary.
+        This should be treated like items of a dictionary. The order
+        here doesn't affect what gets overridden. That is controlled
+        by OVERRIDE_ORDER. However this does control the order they are
+        displayed to the user. It's probably most ergononmic to display
+        things in the same order as OVERRIDE_ORDER
         """
         # SMELL: Move the conditions out of this function
 
-        # environment variables have the lowest priority
-        config_file = os.environ.get("PIP_CONFIG_FILE", None)
-        if config_file is not None:
-            yield kinds.ENV, [config_file]
-        else:
-            yield kinds.ENV, []
-
+        env_config_file = os.environ.get("PIP_CONFIG_FILE", None)
         config_files = get_configuration_files()
 
-        # at the base we have any global configuration
         yield kinds.GLOBAL, config_files[kinds.GLOBAL]
 
-        # per-user configuration next
+        # per-user config is not loaded when env_config_file exists
         should_load_user_config = not self.isolated and not (
-            config_file and os.path.exists(config_file)
+            env_config_file and os.path.exists(env_config_file)
         )
         if should_load_user_config:
             # The legacy config file is overridden by the new config file
             yield kinds.USER, config_files[kinds.USER]
 
-        # finally virtualenv configuration first trumping others
+        # virtualenv config
         yield kinds.SITE, config_files[kinds.SITE]
 
+        if env_config_file is not None:
+            yield kinds.ENV, [env_config_file]
+        else:
+            yield kinds.ENV, []
+
     def get_values_in_config(self, variant: Kind) -> Dict[str, Any]:
         """Get values present in a config file"""
         return self._config[variant]

src/pip/_internal/exceptions.py

@@ -247,10 +247,7 @@ class NoneMetadataError(PipError):
     def __str__(self) -> str:
         # Use `dist` in the error message because its stringification
         # includes more information, like the version and location.
-        return "None {} metadata found for distribution: {}".format(
-            self.metadata_name,
-            self.dist,
-        )
+        return f"None {self.metadata_name} metadata found for distribution: {self.dist}"
 
 
 class UserInstallationInvalid(InstallationError):
@@ -594,7 +591,7 @@ class HashMismatch(HashError):
         self.gots = gots
 
     def body(self) -> str:
-        return "    {}:\n{}".format(self._requirement_name(), self._hash_comparison())
+        return f"    {self._requirement_name()}:\n{self._hash_comparison()}"
 
     def _hash_comparison(self) -> str:
         """
@@ -616,11 +613,9 @@ class HashMismatch(HashError):
         lines: List[str] = []
         for hash_name, expecteds in self.allowed.items():
             prefix = hash_then_or(hash_name)
-            lines.extend(
-                ("        Expected {} {}".format(next(prefix), e)) for e in expecteds
-            )
+            lines.extend((f"        Expected {next(prefix)} {e}") for e in expecteds)
             lines.append(
-                "             Got        {}\n".format(self.gots[hash_name].hexdigest())
+                f"             Got        {self.gots[hash_name].hexdigest()}\n"
             )
         return "\n".join(lines)
 

src/pip/_internal/index/package_finder.py

@@ -533,8 +533,8 @@ class CandidateEvaluator:
                 )
             except ValueError:
                 raise UnsupportedWheel(
-                    "{} is not a supported wheel for this platform. It "
-                    "can't be sorted.".format(wheel.filename)
+                    f"{wheel.filename} is not a supported wheel for this platform. It "
+                    "can't be sorted."
                 )
             if self._prefer_binary:
                 binary_preference = 1
@@ -939,9 +939,7 @@ class PackageFinder:
                 _format_versions(best_candidate_result.iter_all()),
             )
 
-            raise DistributionNotFound(
-                "No matching distribution found for {}".format(req)
-            )
+            raise DistributionNotFound(f"No matching distribution found for {req}")
 
         def _should_install_candidate(
             candidate: Optional[InstallationCandidate],

src/pip/_internal/locations/_distutils.py

@@ -56,8 +56,7 @@ def distutils_scheme(
         try:
             d.parse_config_files()
         except UnicodeDecodeError:
-            # Typeshed does not include find_config_files() for some reason.
-            paths = d.find_config_files()  # type: ignore
+            paths = d.find_config_files()
             logger.warning(
                 "Ignore distutils configs in %s due to encoding errors.",
                 ", ".join(os.path.basename(p) for p in paths),

src/pip/_internal/metadata/_json.py

@@ -64,10 +64,10 @@ def msg_to_json(msg: Message) -> Dict[str, Any]:
         key = json_name(field)
         if multi:
             value: Union[str, List[str]] = [
-                sanitise_header(v) for v in msg.get_all(field)
+                sanitise_header(v) for v in msg.get_all(field)  # type: ignore
             ]
         else:
-            value = sanitise_header(msg.get(field))
+            value = sanitise_header(msg.get(field))  # type: ignore
             if key == "keywords":
                 # Accept both comma-separated and space-separated
                 # forms, for better compatibility with old data.

src/pip/_internal/models/candidate.py

@@ -27,8 +27,4 @@ class InstallationCandidate(KeyBasedCompareMixin):
         )
 
     def __str__(self) -> str:
-        return "{!r} candidate (version {} at {})".format(
-            self.name,
-            self.version,
-            self.link,
-        )
+        return f"{self.name!r} candidate (version {self.version} at {self.link})"

src/pip/_internal/models/direct_url.py

@@ -31,9 +31,7 @@ def _get(
     value = d[key]
     if not isinstance(value, expected_type):
         raise DirectUrlValidationError(
-            "{!r} has unexpected type for {} (expected {})".format(
-                value, key, expected_type
-            )
+            f"{value!r} has unexpected type for {key} (expected {expected_type})"
         )
     return value
 

src/pip/_internal/models/format_control.py

@@ -33,9 +33,7 @@ class FormatControl:
         return all(getattr(self, k) == getattr(other, k) for k in self.__slots__)
 
     def __repr__(self) -> str:
-        return "{}({}, {})".format(
-            self.__class__.__name__, self.no_binary, self.only_binary
-        )
+        return f"{self.__class__.__name__}({self.no_binary}, {self.only_binary})"
 
     @staticmethod
     def handle_mutual_excludes(value: str, target: Set[str], other: Set[str]) -> None:

src/pip/_internal/models/link.py

@@ -368,9 +368,7 @@ class Link(KeyBasedCompareMixin):
         else:
             rp = ""
         if self.comes_from:
-            return "{} (from {}){}".format(
-                redact_auth_from_url(self._url), self.comes_from, rp
-            )
+            return f"{redact_auth_from_url(self._url)} (from {self.comes_from}){rp}"
         else:
             return redact_auth_from_url(str(self._url))
 

src/pip/_internal/network/download.py

@@ -42,7 +42,7 @@ def _prepare_download(
     logged_url = redact_auth_from_url(url)
 
     if total_length:
-        logged_url = "{} ({})".format(logged_url, format_size(total_length))
+        logged_url = f"{logged_url} ({format_size(total_length)})"
 
     if is_from_cache(resp):
         logger.info("Using cached %s", logged_url)

src/pip/_internal/network/xmlrpc.py

@@ -13,6 +13,8 @@ from pip._internal.network.utils import raise_for_status
 if TYPE_CHECKING:
     from xmlrpc.client import _HostType, _Marshallable
 
+    from _typeshed import SizedBuffer
+
 logger = logging.getLogger(__name__)
 
 
@@ -33,7 +35,7 @@ class PipXmlrpcTransport(xmlrpc.client.Transport):
         self,
         host: "_HostType",
         handler: str,
-        request_body: bytes,
+        request_body: "SizedBuffer",
         verbose: bool = False,
     ) -> Tuple["_Marshallable", ...]:
         assert isinstance(host, str)

src/pip/_internal/operations/install/wheel.py

@@ -164,16 +164,14 @@ def message_about_scripts_not_on_PATH(scripts: Sequence[str]) -> Optional[str]:
     for parent_dir, dir_scripts in warn_for.items():
         sorted_scripts: List[str] = sorted(dir_scripts)
         if len(sorted_scripts) == 1:
-            start_text = "script {} is".format(sorted_scripts[0])
+            start_text = f"script {sorted_scripts[0]} is"
         else:
             start_text = "scripts {} are".format(
                 ", ".join(sorted_scripts[:-1]) + " and " + sorted_scripts[-1]
             )
 
         msg_lines.append(
-            "The {} installed in '{}' which is not on PATH.".format(
-                start_text, parent_dir
-            )
+            f"The {start_text} installed in '{parent_dir}' which is not on PATH."
         )
 
     last_line_fmt = (
@@ -321,9 +319,7 @@ def get_console_script_specs(console: Dict[str, str]) -> List[str]:
             scripts_to_generate.append("pip = " + pip_script)
 
         if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
-            scripts_to_generate.append(
-                "pip{} = {}".format(sys.version_info[0], pip_script)
-            )
+            scripts_to_generate.append(f"pip{sys.version_info[0]} = {pip_script}")
 
         scripts_to_generate.append(f"pip{get_major_minor_version()} = {pip_script}")
         # Delete any other versioned pip entry points
@@ -336,9 +332,7 @@ def get_console_script_specs(console: Dict[str, str]) -> List[str]:
             scripts_to_generate.append("easy_install = " + easy_install_script)
 
         scripts_to_generate.append(
-            "easy_install-{} = {}".format(
-                get_major_minor_version(), easy_install_script
-            )
+            f"easy_install-{get_major_minor_version()} = {easy_install_script}"
         )
         # Delete any other versioned easy_install entry points
         easy_install_ep = [
@@ -408,10 +402,10 @@ class ScriptFile:
 class MissingCallableSuffix(InstallationError):
     def __init__(self, entry_point: str) -> None:
         super().__init__(
-            "Invalid script entry point: {} - A callable "
+            f"Invalid script entry point: {entry_point} - A callable "
             "suffix is required. Cf https://packaging.python.org/"
             "specifications/entry-points/#use-for-scripts for more "
-            "information.".format(entry_point)
+            "information."
         )
 
 
@@ -712,7 +706,7 @@ def req_error_context(req_description: str) -> Generator[None, None, None]:
     try:
         yield
     except InstallationError as e:
-        message = "For req: {}. {}".format(req_description, e.args[0])
+        message = f"For req: {req_description}. {e.args[0]}"
         raise InstallationError(message) from e
 
 

src/pip/_internal/operations/prepare.py

@@ -603,8 +603,8 @@ class RequirementPreparer:
                 )
             except NetworkConnectionError as exc:
                 raise InstallationError(
-                    "Could not install requirement {} because of HTTP "
-                    "error {} for URL {}".format(req, exc, link)
+                    f"Could not install requirement {req} because of HTTP "
+                    f"error {exc} for URL {link}"
                 )
         else:
             file_path = self._downloaded[link.url]
@@ -684,9 +684,9 @@ class RequirementPreparer:
         with indent_log():
             if self.require_hashes:
                 raise InstallationError(
-                    "The editable requirement {} cannot be installed when "
+                    f"The editable requirement {req} cannot be installed when "
                     "requiring hashes, because there is no single file to "
-                    "hash.".format(req)
+                    "hash."
                 )
             req.ensure_has_source_dir(self.src_dir)
             req.update_editable()
@@ -714,7 +714,7 @@ class RequirementPreparer:
         assert req.satisfied_by, "req should have been satisfied but isn't"
         assert skip_reason is not None, (
             "did not get skip reason skipped but req.satisfied_by "
-            "is set to {}".format(req.satisfied_by)
+            f"is set to {req.satisfied_by}"
         )
         logger.info(
             "Requirement %s: %s (%s)", skip_reason, req, req.satisfied_by.version

src/pip/_internal/req/constructors.py

@@ -462,7 +462,7 @@ def install_req_from_req_string(
         raise InstallationError(
             "Packages installed from PyPI cannot depend on packages "
             "which are not also hosted on PyPI.\n"
-            "{} depends on {} ".format(comes_from.name, req)
+            f"{comes_from.name} depends on {req} "
         )
 
     return InstallRequirement(

src/pip/_internal/req/req_install.py

@@ -191,7 +191,7 @@ class InstallRequirement:
         if self.req:
             s = redact_auth_from_requirement(self.req)
             if self.link:
-                s += " from {}".format(redact_auth_from_url(self.link.url))
+                s += f" from {redact_auth_from_url(self.link.url)}"
         elif self.link:
             s = redact_auth_from_url(self.link.url)
         else:
@@ -221,7 +221,7 @@ class InstallRequirement:
         attributes = vars(self)
         names = sorted(attributes)
 
-        state = ("{}={!r}".format(attr, attributes[attr]) for attr in sorted(names))
+        state = (f"{attr}={attributes[attr]!r}" for attr in sorted(names))
         return "<{name} object: {{{state}}}>".format(
             name=self.__class__.__name__,
             state=", ".join(state),
@@ -754,8 +754,8 @@ class InstallRequirement:
 
         if os.path.exists(archive_path):
             response = ask_path_exists(
-                "The file {} exists. (i)gnore, (w)ipe, "
-                "(b)ackup, (a)bort ".format(display_path(archive_path)),
+                f"The file {display_path(archive_path)} exists. (i)gnore, (w)ipe, "
+                "(b)ackup, (a)bort ",
                 ("i", "w", "b", "a"),
             )
             if response == "i":

src/pip/_internal/req/req_uninstall.py

@@ -71,16 +71,16 @@ def uninstallation_paths(dist: BaseDistribution) -> Generator[str, None, None]:
 
     entries = dist.iter_declared_entries()
     if entries is None:
-        msg = "Cannot uninstall {dist}, RECORD file not found.".format(dist=dist)
+        msg = f"Cannot uninstall {dist}, RECORD file not found."
         installer = dist.installer
         if not installer or installer == "pip":
-            dep = "{}=={}".format(dist.raw_name, dist.version)
+            dep = f"{dist.raw_name}=={dist.version}"
             msg += (
                 " You might be able to recover from this via: "
-                "'pip install --force-reinstall --no-deps {}'.".format(dep)
+                f"'pip install --force-reinstall --no-deps {dep}'."
             )
         else:
-            msg += " Hint: The package was installed by {}.".format(installer)
+            msg += f" Hint: The package was installed by {installer}."
         raise UninstallationError(msg)
 
     for entry in entries:

src/pip/_internal/resolution/legacy/resolver.py

@@ -231,9 +231,7 @@ class Resolver(BaseResolver):
             tags = compatibility_tags.get_supported()
             if requirement_set.check_supported_wheels and not wheel.supported(tags):
                 raise InstallationError(
-                    "{} is not a supported wheel on this platform.".format(
-                        wheel.filename
-                    )
+                    f"{wheel.filename} is not a supported wheel on this platform."
                 )
 
         # This next bit is really a sanity check.
@@ -287,9 +285,9 @@ class Resolver(BaseResolver):
         )
         if does_not_satisfy_constraint:
             raise InstallationError(
-                "Could not satisfy constraints for '{}': "
+                f"Could not satisfy constraints for '{install_req.name}': "
                 "installation from path or url cannot be "
-                "constrained to a version".format(install_req.name)
+                "constrained to a version"
             )
         # If we're now installing a constraint, mark the existing
         # object for real installation.
@@ -398,9 +396,9 @@ class Resolver(BaseResolver):
                 # "UnicodeEncodeError: 'ascii' codec can't encode character"
                 # in Python 2 when the reason contains non-ascii characters.
                 "The candidate selected for download or install is a "
-                "yanked version: {candidate}\n"
-                "Reason for being yanked: {reason}"
-            ).format(candidate=best_candidate, reason=reason)
+                f"yanked version: {best_candidate}\n"
+                f"Reason for being yanked: {reason}"
+            )
             logger.warning(msg)
 
         return link

src/pip/_internal/resolution/resolvelib/candidates.py

@@ -159,10 +159,7 @@ class _InstallRequirementBackedCandidate(Candidate):
         return f"{self.name} {self.version}"
 
     def __repr__(self) -> str:
-        return "{class_name}({link!r})".format(
-            class_name=self.__class__.__name__,
-            link=str(self._link),
-        )
+        return f"{self.__class__.__name__}({str(self._link)!r})"
 
     def __hash__(self) -> int:
         return hash((self.__class__, self._link))
@@ -354,10 +351,7 @@ class AlreadyInstalledCandidate(Candidate):
         return str(self.dist)
 
     def __repr__(self) -> str:
-        return "{class_name}({distribution!r})".format(
-            class_name=self.__class__.__name__,
-            distribution=self.dist,
-        )
+        return f"{self.__class__.__name__}({self.dist!r})"
 
     def __hash__(self) -> int:
         return hash((self.__class__, self.name, self.version))
@@ -455,11 +449,7 @@ class ExtrasCandidate(Candidate):
         return "{}[{}] {}".format(name, ",".join(self.extras), rest)
 
     def __repr__(self) -> str:
-        return "{class_name}(base={base!r}, extras={extras!r})".format(
-            class_name=self.__class__.__name__,
-            base=self.base,
-            extras=self.extras,
-        )
+        return f"{self.__class__.__name__}(base={self.base!r}, extras={self.extras!r})"
 
     def __hash__(self) -> int:
         return hash((self.base, self.extras))

src/pip/_internal/resolution/resolvelib/factory.py

@@ -753,8 +753,8 @@ class Factory:
             info = "the requested packages"
 
         msg = (
-            "Cannot install {} because these package versions "
-            "have conflicting dependencies.".format(info)
+            f"Cannot install {info} because these package versions "
+            "have conflicting dependencies."
         )
         logger.critical(msg)
         msg = "\nThe conflict is caused by:"

src/pip/_internal/resolution/resolvelib/requirements.py

@@ -15,10 +15,7 @@ class ExplicitRequirement(Requirement):
         return str(self.candidate)
 
     def __repr__(self) -> str:
-        return "{class_name}({candidate!r})".format(
-            class_name=self.__class__.__name__,
-            candidate=self.candidate,
-        )
+        return f"{self.__class__.__name__}({self.candidate!r})"
 
     @property
     def project_name(self) -> NormalizedName:
@@ -50,10 +47,7 @@ class SpecifierRequirement(Requirement):
         return str(self._ireq.req)
 
     def __repr__(self) -> str:
-        return "{class_name}({requirement!r})".format(
-            class_name=self.__class__.__name__,
-            requirement=str(self._ireq.req),
-        )
+        return f"{self.__class__.__name__}({str(self._ireq.req)!r})"
 
     @property
     def project_name(self) -> NormalizedName:
@@ -116,10 +110,7 @@ class RequiresPythonRequirement(Requirement):
         return f"Python {self.specifier}"
 
     def __repr__(self) -> str:
-        return "{class_name}({specifier!r})".format(
-            class_name=self.__class__.__name__,
-            specifier=str(self.specifier),
-        )
+        return f"{self.__class__.__name__}({str(self.specifier)!r})"
 
     @property
     def project_name(self) -> NormalizedName:
@@ -155,10 +146,7 @@ class UnsatisfiableRequirement(Requirement):
         return f"{self._name} (unavailable)"
 
     def __repr__(self) -> str:
-        return "{class_name}({name!r})".format(
-            class_name=self.__class__.__name__,
-            name=str(self._name),
-        )
+        return f"{self.__class__.__name__}({str(self._name)!r})"
 
     @property
     def project_name(self) -> NormalizedName:

src/pip/_internal/utils/misc.py

@@ -77,11 +77,7 @@ def get_pip_version() -> str:
     pip_pkg_dir = os.path.join(os.path.dirname(__file__), "..", "..")
     pip_pkg_dir = os.path.abspath(pip_pkg_dir)
 
-    return "pip {} from {} (python {})".format(
-        __version__,
-        pip_pkg_dir,
-        get_major_minor_version(),
-    )
+    return f"pip {__version__} from {pip_pkg_dir} (python {get_major_minor_version()})"
 
 
 def normalize_version_info(py_version_info: Tuple[int, ...]) -> Tuple[int, int, int]:
@@ -145,9 +141,9 @@ def rmtree(
     )
     if sys.version_info >= (3, 12):
         # See https://docs.python.org/3.12/whatsnew/3.12.html#shutil.
-        shutil.rmtree(dir, onexc=handler)
+        shutil.rmtree(dir, onexc=handler)  # type: ignore
     else:
-        shutil.rmtree(dir, onerror=handler)
+        shutil.rmtree(dir, onerror=handler)  # type: ignore
 
 
 def _onerror_ignore(*_args: Any) -> None:
@@ -279,13 +275,13 @@ def strtobool(val: str) -> int:
 
 def format_size(bytes: float) -> str:
     if bytes > 1000 * 1000:
-        return "{:.1f} MB".format(bytes / 1000.0 / 1000)
+        return f"{bytes / 1000.0 / 1000:.1f} MB"
     elif bytes > 10 * 1000:
-        return "{} kB".format(int(bytes / 1000))
+        return f"{int(bytes / 1000)} kB"
     elif bytes > 1000:
-        return "{:.1f} kB".format(bytes / 1000.0)
+        return f"{bytes / 1000.0:.1f} kB"
     else:
-        return "{} bytes".format(int(bytes))
+        return f"{int(bytes)} bytes"
 
 
 def tabulate(rows: Iterable[Iterable[Any]]) -> Tuple[List[str], List[int]]:
@@ -522,9 +518,7 @@ def redact_netloc(netloc: str) -> str:
     else:
         user = urllib.parse.quote(user)
         password = ":****"
-    return "{user}{password}@{netloc}".format(
-        user=user, password=password, netloc=netloc
-    )
+    return f"{user}{password}@{netloc}"
 
 
 def _transform_url(
@@ -592,7 +586,7 @@ class HiddenText:
         self.redacted = redacted
 
     def __repr__(self) -> str:
-        return "<HiddenText {!r}>".format(str(self))
+        return f"<HiddenText {str(self)!r}>"
 
     def __str__(self) -> str:
         return self.redacted

src/pip/_internal/utils/wheel.py

@@ -28,7 +28,7 @@ def parse_wheel(wheel_zip: ZipFile, name: str) -> Tuple[str, Message]:
         metadata = wheel_metadata(wheel_zip, info_dir)
         version = wheel_version(metadata)
     except UnsupportedWheel as e:
-        raise UnsupportedWheel("{} has an invalid wheel, {}".format(name, str(e)))
+        raise UnsupportedWheel(f"{name} has an invalid wheel, {str(e)}")
 
     check_compatibility(version, name)
 
@@ -60,9 +60,7 @@ def wheel_dist_info_dir(source: ZipFile, name: str) -> str:
     canonical_name = canonicalize_name(name)
     if not info_dir_name.startswith(canonical_name):
         raise UnsupportedWheel(
-            ".dist-info directory {!r} does not start with {!r}".format(
-                info_dir, canonical_name
-            )
+            f".dist-info directory {info_dir!r} does not start with {canonical_name!r}"
         )
 
     return info_dir

src/pip/_internal/vcs/mercurial.py

@@ -31,7 +31,7 @@ class Mercurial(VersionControl):
 
     @staticmethod
     def get_base_rev_args(rev: str) -> List[str]:
-        return [f"-r={rev}"]
+        return [f"--rev={rev}"]
 
     def fetch_new(
         self, dest: str, url: HiddenText, rev_options: RevOptions, verbosity: int

src/pip/_internal/vcs/versioncontrol.py

@@ -405,9 +405,9 @@ class VersionControl:
         scheme, netloc, path, query, frag = urllib.parse.urlsplit(url)
         if "+" not in scheme:
             raise ValueError(
-                "Sorry, {!r} is a malformed VCS url. "
+                f"Sorry, {url!r} is a malformed VCS url. "
                 "The format is <vcs>+<protocol>://<url>, "
-                "e.g. svn+http://myrepo/svn/MyApp#egg=MyApp".format(url)
+                "e.g. svn+http://myrepo/svn/MyApp#egg=MyApp"
             )
         # Remove the vcs prefix.
         scheme = scheme.split("+", 1)[1]
@@ -417,9 +417,9 @@ class VersionControl:
             path, rev = path.rsplit("@", 1)
             if not rev:
                 raise InstallationError(
-                    "The URL {!r} has an empty revision (after @) "
+                    f"The URL {url!r} has an empty revision (after @) "
                     "which is not supported. Include a revision after @ "
-                    "or remove @ from the URL.".format(url)
+                    "or remove @ from the URL."
                 )
         url = urllib.parse.urlunsplit((scheme, netloc, path, query, ""))
         return url, rev, user_pass
@@ -566,7 +566,7 @@ class VersionControl:
             self.name,
             url,
         )
-        response = ask_path_exists("What to do?  {}".format(prompt[0]), prompt[1])
+        response = ask_path_exists(f"What to do?  {prompt[0]}", prompt[1])
 
         if response == "a":
             sys.exit(-1)

src/pip/_internal/wheel_builder.py

@@ -140,15 +140,15 @@ def _verify_one(req: InstallRequirement, wheel_path: str) -> None:
     w = Wheel(os.path.basename(wheel_path))
     if canonicalize_name(w.name) != canonical_name:
         raise InvalidWheelFilename(
-            "Wheel has unexpected file name: expected {!r}, "
-            "got {!r}".format(canonical_name, w.name),
+            f"Wheel has unexpected file name: expected {canonical_name!r}, "
+            f"got {w.name!r}",
         )
     dist = get_wheel_distribution(FilesystemWheel(wheel_path), canonical_name)
     dist_verstr = str(dist.version)
     if canonicalize_version(dist_verstr) != canonicalize_version(w.version):
         raise InvalidWheelFilename(
-            "Wheel has unexpected file name: expected {!r}, "
-            "got {!r}".format(dist_verstr, w.version),
+            f"Wheel has unexpected file name: expected {dist_verstr!r}, "
+            f"got {w.version!r}",
         )
     metadata_version_value = dist.metadata_version
     if metadata_version_value is None:
@@ -160,8 +160,7 @@ def _verify_one(req: InstallRequirement, wheel_path: str) -> None:
         raise UnsupportedWheel(msg)
     if metadata_version >= Version("1.2") and not isinstance(dist.version, Version):
         raise UnsupportedWheel(
-            "Metadata 1.2 mandates PEP 440 version, "
-            "but {!r} is not".format(dist_verstr)
+            f"Metadata 1.2 mandates PEP 440 version, but {dist_verstr!r} is not"
         )
 
 

tests/conftest.py

@@ -14,6 +14,7 @@ from hashlib import sha256
 from pathlib import Path
 from textwrap import dedent
 from typing import (
+    TYPE_CHECKING,
     Any,
     AnyStr,
     Callable,
@@ -58,6 +59,9 @@ from tests.lib import (
 from tests.lib.server import MockServer, make_mock_server
 from tests.lib.venv import VirtualEnvironment, VirtualEnvironmentType
 
+if TYPE_CHECKING:
+    from pip._vendor.typing_extensions import Self
+
 
 def pytest_addoption(parser: Parser) -> None:
     parser.addoption(
@@ -141,7 +145,7 @@ def pytest_collection_modifyitems(config: Config, items: List[pytest.Function])
             if "script" in item.fixturenames:
                 raise RuntimeError(
                     "Cannot use the ``script`` funcarg in a unit test: "
-                    "(filename = {}, item = {})".format(module_path, item)
+                    f"(filename = {module_path}, item = {item})"
                 )
         else:
             raise RuntimeError(f"Unknown test type (filename = {module_path})")
@@ -941,7 +945,7 @@ def html_index_with_onetime_server(
     """
 
     class InDirectoryServer(http.server.ThreadingHTTPServer):
-        def finish_request(self, request: Any, client_address: Any) -> None:
+        def finish_request(self: "Self", request: Any, client_address: Any) -> None:
             self.RequestHandlerClass(
                 request,
                 client_address,

tests/functional/test_cli.py

@@ -23,7 +23,7 @@ def test_entrypoints_work(entrypoint: str, script: PipTestEnvironment) -> None:
     fake_pkg.mkdir()
     fake_pkg.joinpath("setup.py").write_text(
         dedent(
-            """
+            f"""
     from setuptools import setup
 
     setup(
@@ -31,13 +31,11 @@ def test_entrypoints_work(entrypoint: str, script: PipTestEnvironment) -> None:
         version="0.1.0",
         entry_points={{
             "console_scripts": [
-                {!r}
+                {entrypoint!r}
             ]
         }}
     )
-    """.format(
-                entrypoint
-            )
+    """
         )
     )
 

tests/functional/test_completion.py

@@ -400,7 +400,7 @@ def test_completion_path_after_option(
 def test_completion_uses_same_executable_name(
     autocomplete_script: PipTestEnvironment, flag: str, deprecated_python: bool
 ) -> None:
-    executable_name = "pip{}".format(sys.version_info[0])
+    executable_name = f"pip{sys.version_info[0]}"
     # Deprecated python versions produce an extra deprecation warning
     result = autocomplete_script.run(
         executable_name,

tests/functional/test_debug.py

@@ -68,7 +68,7 @@ def test_debug__tags(script: PipTestEnvironment, args: List[str]) -> None:
     stdout = result.stdout
 
     tags = compatibility_tags.get_supported()
-    expected_tag_header = "Compatible tags: {}".format(len(tags))
+    expected_tag_header = f"Compatible tags: {len(tags)}"
     assert expected_tag_header in stdout
 
     show_verbose_note = "--verbose" not in args

tests/functional/test_freeze.py

@@ -166,13 +166,11 @@ def test_freeze_with_invalid_names(script: PipTestEnvironment) -> None:
         with open(egg_info_path, "w") as egg_info_file:
             egg_info_file.write(
                 textwrap.dedent(
-                    """\
+                    f"""\
                 Metadata-Version: 1.0
-                Name: {}
+                Name: {pkgname}
                 Version: 1.0
-                """.format(
-                        pkgname
-                    )
+                """
                 )
             )
 
@@ -221,12 +219,10 @@ def test_freeze_editable_not_vcs(script: PipTestEnvironment) -> None:
     # We need to apply os.path.normcase() to the path since that is what
     # the freeze code does.
     expected = textwrap.dedent(
-        """\
+        f"""\
     ...# Editable install with no version control (version-pkg==0.1)
-    -e {}
-    ...""".format(
-            os.path.normcase(pkg_path)
-        )
+    -e {os.path.normcase(pkg_path)}
+    ..."""
     )
     _check_output(result.stdout, expected)
 
@@ -248,12 +244,10 @@ def test_freeze_editable_git_with_no_remote(
     # We need to apply os.path.normcase() to the path since that is what
     # the freeze code does.
     expected = textwrap.dedent(
-        """\
+        f"""\
     ...# Editable Git install with no remote (version-pkg==0.1)
-    -e {}
-    ...""".format(
-            os.path.normcase(pkg_path)
-        )
+    -e {os.path.normcase(pkg_path)}
+    ..."""
     )
     _check_output(result.stdout, expected)
 
@@ -653,9 +647,9 @@ def test_freeze_with_requirement_option_file_url_egg_not_installed(
         expect_stderr=True,
     )
     expected_err = (
-        "WARNING: Requirement file [requirements.txt] contains {}, "
+        f"WARNING: Requirement file [requirements.txt] contains {url}, "
         "but package 'Does.Not-Exist' is not installed\n"
-    ).format(url)
+    )
     if deprecated_python:
         assert expected_err in result.stderr
     else:

tests/functional/test_install.py

@@ -106,10 +106,10 @@ def test_pep518_refuses_conflicting_requires(
     assert (
         result.returncode != 0
         and (
-            "Some build dependencies for {url} conflict "
+            f"Some build dependencies for {project_dir.as_uri()} conflict "
             "with PEP 517/518 supported "
             "requirements: setuptools==1.0 is incompatible with "
-            "setuptools>=40.8.0.".format(url=project_dir.as_uri())
+            "setuptools>=40.8.0."
         )
         in result.stderr
     ), str(result)
@@ -595,8 +595,8 @@ def test_hashed_install_success(
     with requirements_file(
         "simple2==1.0 --hash=sha256:9336af72ca661e6336eb87bc7de3e8844d853e"
         "3848c2b9bbd2e8bf01db88c2c7\n"
-        "{simple} --hash=sha256:393043e672415891885c9a2a0929b1af95fb866d6c"
-        "a016b42d2e6ce53619b653".format(simple=file_url),
+        f"{file_url} --hash=sha256:393043e672415891885c9a2a0929b1af95fb866d6c"
+        "a016b42d2e6ce53619b653",
         tmpdir,
     ) as reqs_file:
         script.pip_install_local("-r", reqs_file.resolve())
@@ -1735,7 +1735,7 @@ def test_install_builds_wheels(script: PipTestEnvironment, data: TestData) -> No
     # into the cache
     assert wheels != [], str(res)
     assert wheels == [
-        "Upper-2.0-py{}-none-any.whl".format(sys.version_info[0]),
+        f"Upper-2.0-py{sys.version_info[0]}-none-any.whl",
     ]
 
 
@@ -2387,7 +2387,7 @@ def test_install_verify_package_name_normalization(
     assert "Successfully installed simple-package" in result.stdout
 
     result = script.pip("install", package_name)
-    assert "Requirement already satisfied: {}".format(package_name) in result.stdout
+    assert f"Requirement already satisfied: {package_name}" in result.stdout
 
 
 def test_install_logs_pip_version_in_debug(

tests/functional/test_install_config.py

@@ -184,12 +184,10 @@ def test_config_file_override_stack(
 
     config_file.write_text(
         textwrap.dedent(
-            """\
+            f"""\
         [global]
-        index-url = {}/simple1
-        """.format(
-                base_address
-            )
+        index-url = {base_address}/simple1
+        """
         )
     )
     script.pip("install", "-vvv", "INITools", expect_error=True)
@@ -197,14 +195,12 @@ def test_config_file_override_stack(
 
     config_file.write_text(
         textwrap.dedent(
-            """\
+            f"""\
         [global]
-        index-url = {address}/simple1
+        index-url = {base_address}/simple1
         [install]
-        index-url = {address}/simple2
-        """.format(
-                address=base_address
-            )
+        index-url = {base_address}/simple2
+        """
         )
     )
     script.pip("install", "-vvv", "INITools", expect_error=True)

tests/functional/test_install_index.py

@@ -41,13 +41,11 @@ def test_find_links_requirements_file_relative_path(
     """Test find-links as a relative path to a reqs file."""
     script.scratch_path.joinpath("test-req.txt").write_text(
         textwrap.dedent(
-            """
+            f"""
         --no-index
-        --find-links={}
+        --find-links={data.packages.as_posix()}
         parent==0.1
-        """.format(
-                data.packages.as_posix()
-            )
+        """
         )
     )
     result = script.pip(

tests/functional/test_install_reqs.py

@@ -95,7 +95,7 @@ def test_requirements_file(script: PipTestEnvironment) -> None:
     result.did_create(script.site_packages / "INITools-0.2.dist-info")
     result.did_create(script.site_packages / "initools")
     assert result.files_created[script.site_packages / other_lib_name].dir
-    fn = "{}-{}.dist-info".format(other_lib_name, other_lib_version)
+    fn = f"{other_lib_name}-{other_lib_version}.dist-info"
     assert result.files_created[script.site_packages / fn].dir
 
 
@@ -260,13 +260,13 @@ def test_respect_order_in_requirements_file(
 
     assert (
         "parent" in downloaded[0]
-    ), 'First download should be "parent" but was "{}"'.format(downloaded[0])
+    ), f'First download should be "parent" but was "{downloaded[0]}"'
     assert (
         "child" in downloaded[1]
-    ), 'Second download should be "child" but was "{}"'.format(downloaded[1])
+    ), f'Second download should be "child" but was "{downloaded[1]}"'
     assert (
         "simple" in downloaded[2]
-    ), 'Third download should be "simple" but was "{}"'.format(downloaded[2])
+    ), f'Third download should be "simple" but was "{downloaded[2]}"'
 
 
 def test_install_local_editable_with_extras(

tests/functional/test_install_wheel.py

@@ -169,9 +169,9 @@ def get_header_scheme_path_for_script(
 ) -> Path:
     command = (
         "from pip._internal.locations import get_scheme;"
-        "scheme = get_scheme({!r});"
+        f"scheme = get_scheme({dist_name!r});"
         "print(scheme.headers);"
-    ).format(dist_name)
+    )
     result = script.run("python", "-c", command).stdout
     return Path(result.strip())
 

tests/functional/test_new_resolver.py

@@ -1185,7 +1185,7 @@ def test_new_resolver_presents_messages_when_backtracking_a_lot(
     for index in range(1, N + 1):
         A_version = f"{index}.0.0"
         B_version = f"{index}.0.0"
-        C_version = "{index_minus_one}.0.0".format(index_minus_one=index - 1)
+        C_version = f"{index - 1}.0.0"
 
         depends = ["B == " + B_version]
         if index != 1:

tests/functional/test_new_resolver_errors.py

@@ -71,8 +71,8 @@ def test_new_resolver_conflict_constraints_file(
 
 
 def test_new_resolver_requires_python_error(script: PipTestEnvironment) -> None:
-    compatible_python = ">={0.major}.{0.minor}".format(sys.version_info)
-    incompatible_python = "<{0.major}.{0.minor}".format(sys.version_info)
+    compatible_python = f">={sys.version_info.major}.{sys.version_info.minor}"
+    incompatible_python = f"<{sys.version_info.major}.{sys.version_info.minor}"
 
     pkga = create_test_package_with_setup(
         script,
@@ -99,7 +99,7 @@ def test_new_resolver_requires_python_error(script: PipTestEnvironment) -> None:
 def test_new_resolver_checks_requires_python_before_dependencies(
     script: PipTestEnvironment,
 ) -> None:
-    incompatible_python = "<{0.major}.{0.minor}".format(sys.version_info)
+    incompatible_python = f"<{sys.version_info.major}.{sys.version_info.minor}"
 
     pkg_dep = create_basic_wheel_for_package(
         script,

tests/functional/test_new_resolver_hashes.py

@@ -24,18 +24,11 @@ def _create_find_links(script: PipTestEnvironment) -> _FindLinks:
 
     index_html = script.scratch_path / "index.html"
     index_html.write_text(
-        """
+        f"""
         <!DOCTYPE html>
-        <a href="{sdist_url}#sha256={sdist_hash}">{sdist_path.stem}</a>
-        <a href="{wheel_url}#sha256={wheel_hash}">{wheel_path.stem}</a>
-        """.format(
-            sdist_url=sdist_path.as_uri(),
-            sdist_hash=sdist_hash,
-            sdist_path=sdist_path,
-            wheel_url=wheel_path.as_uri(),
-            wheel_hash=wheel_hash,
-            wheel_path=wheel_path,
-        ).strip()
+        <a href="{sdist_path.as_uri()}#sha256={sdist_hash}">{sdist_path.stem}</a>
+        <a href="{wheel_path.as_uri()}#sha256={wheel_hash}">{wheel_path.stem}</a>
+        """.strip()
     )
 
     return _FindLinks(index_html, sdist_hash, wheel_hash)
@@ -99,9 +92,7 @@ def test_new_resolver_hash_intersect_from_constraint(
 
     constraints_txt = script.scratch_path / "constraints.txt"
     constraints_txt.write_text(
-        "base==0.1.0 --hash=sha256:{sdist_hash}".format(
-            sdist_hash=find_links.sdist_hash,
-        ),
+        f"base==0.1.0 --hash=sha256:{find_links.sdist_hash}",
     )
     requirements_txt = script.scratch_path / "requirements.txt"
     requirements_txt.write_text(
@@ -200,13 +191,10 @@ def test_new_resolver_hash_intersect_empty_from_constraint(
 
     constraints_txt = script.scratch_path / "constraints.txt"
     constraints_txt.write_text(
-        """
-        base==0.1.0 --hash=sha256:{sdist_hash}
-        base==0.1.0 --hash=sha256:{wheel_hash}
-        """.format(
-            sdist_hash=find_links.sdist_hash,
-            wheel_hash=find_links.wheel_hash,
-        ),
+        f"""
+        base==0.1.0 --hash=sha256:{find_links.sdist_hash}
+        base==0.1.0 --hash=sha256:{find_links.wheel_hash}
+        """,
     )
 
     result = script.pip(
@@ -240,19 +228,15 @@ def test_new_resolver_hash_requirement_and_url_constraint_can_succeed(
 
     requirements_txt = script.scratch_path / "requirements.txt"
     requirements_txt.write_text(
-        """
+        f"""
         base==0.1.0 --hash=sha256:{wheel_hash}
-        """.format(
-            wheel_hash=wheel_hash,
-        ),
+        """,
     )
 
     constraints_txt = script.scratch_path / "constraints.txt"
-    constraint_text = "base @ {wheel_url}\n".format(wheel_url=wheel_path.as_uri())
+    constraint_text = f"base @ {wheel_path.as_uri()}\n"
     if constrain_by_hash:
-        constraint_text += "base==0.1.0 --hash=sha256:{wheel_hash}\n".format(
-            wheel_hash=wheel_hash,
-        )
+        constraint_text += f"base==0.1.0 --hash=sha256:{wheel_hash}\n"
     constraints_txt.write_text(constraint_text)
 
     script.pip(
@@ -280,19 +264,15 @@ def test_new_resolver_hash_requirement_and_url_constraint_can_fail(
 
     requirements_txt = script.scratch_path / "requirements.txt"
     requirements_txt.write_text(
-        """
+        f"""
         base==0.1.0 --hash=sha256:{other_hash}
-        """.format(
-            other_hash=other_hash,
-        ),
+        """,
     )
 
     constraints_txt = script.scratch_path / "constraints.txt"
-    constraint_text = "base @ {wheel_url}\n".format(wheel_url=wheel_path.as_uri())
+    constraint_text = f"base @ {wheel_path.as_uri()}\n"
     if constrain_by_hash:
-        constraint_text += "base==0.1.0 --hash=sha256:{other_hash}\n".format(
-            other_hash=other_hash,
-        )
+        constraint_text += f"base==0.1.0 --hash=sha256:{other_hash}\n"
     constraints_txt.write_text(constraint_text)
 
     result = script.pip(
@@ -343,17 +323,12 @@ def test_new_resolver_hash_with_extras(script: PipTestEnvironment) -> None:
 
     requirements_txt = script.scratch_path / "requirements.txt"
     requirements_txt.write_text(
-        """
+        f"""
         child[extra]==0.1.0 --hash=sha256:{child_hash}
         parent_with_extra==0.1.0 --hash=sha256:{parent_with_extra_hash}
         parent_without_extra==0.1.0 --hash=sha256:{parent_without_extra_hash}
         extra==0.1.0 --hash=sha256:{extra_hash}
-        """.format(
-            child_hash=child_hash,
-            parent_with_extra_hash=parent_with_extra_hash,
-            parent_without_extra_hash=parent_without_extra_hash,
-            extra_hash=extra_hash,
-        ),
+        """,
     )
 
     script.pip(

tests/functional/test_new_resolver_target.py

@@ -58,12 +58,7 @@ def test_new_resolver_target_checks_compatibility_failure(
     if platform:
         args += ["--platform", platform]
 
-    args_tag = "{}{}-{}-{}".format(
-        implementation,
-        python_version,
-        abi,
-        platform,
-    )
+    args_tag = f"{implementation}{python_version}-{abi}-{platform}"
     wheel_tag_matches = args_tag == fake_wheel_tag
 
     result = script.pip(*args, expect_error=(not wheel_tag_matches))

tests/functional/test_pep517.py

@@ -159,9 +159,9 @@ def test_conflicting_pep517_backend_requirements(
         expect_error=True,
     )
     msg = (
-        "Some build dependencies for {url} conflict with the backend "
+        f"Some build dependencies for {project_dir.as_uri()} conflict with the backend "
         "dependencies: simplewheel==1.0 is incompatible with "
-        "simplewheel==2.0.".format(url=project_dir.as_uri())
+        "simplewheel==2.0."
     )
     assert result.returncode != 0 and msg in result.stderr, str(result)
 
@@ -205,8 +205,8 @@ def test_validate_missing_pep517_backend_requirements(
         expect_error=True,
     )
     msg = (
-        "Some build dependencies for {url} are missing: "
-        "'simplewheel==1.0', 'test_backend'.".format(url=project_dir.as_uri())
+        f"Some build dependencies for {project_dir.as_uri()} are missing: "
+        "'simplewheel==1.0', 'test_backend'."
     )
     assert result.returncode != 0 and msg in result.stderr, str(result)
 
@@ -231,9 +231,9 @@ def test_validate_conflicting_pep517_backend_requirements(
         expect_error=True,
     )
     msg = (
-        "Some build dependencies for {url} conflict with the backend "
+        f"Some build dependencies for {project_dir.as_uri()} conflict with the backend "
         "dependencies: simplewheel==2.0 is incompatible with "
-        "simplewheel==1.0.".format(url=project_dir.as_uri())
+        "simplewheel==1.0."
     )
     assert result.returncode != 0 and msg in result.stderr, str(result)
 

tests/functional/test_uninstall.py

@@ -604,9 +604,7 @@ def test_uninstall_without_record_fails(
             "simple.dist==0.1'."
         )
     elif installer:
-        expected_error_message += " Hint: The package was installed by {}.".format(
-            installer
-        )
+        expected_error_message += f" Hint: The package was installed by {installer}."
     assert result2.stderr.rstrip() == expected_error_message
     assert_all_changes(result.files_after, result2, ignore_changes)
 

tests/functional/test_wheel.py

@@ -59,9 +59,7 @@ def test_pip_wheel_success(script: PipTestEnvironment, data: TestData) -> None:
     wheel_file_path = script.scratch / wheel_file_name
     assert re.search(
         r"Created wheel for simple: "
-        r"filename={filename} size=\d+ sha256=[A-Fa-f0-9]{{64}}".format(
-            filename=re.escape(wheel_file_name)
-        ),
+        rf"filename={re.escape(wheel_file_name)} size=\d+ sha256=[A-Fa-f0-9]{{64}}",
         result.stdout,
     )
     assert re.search(r"^\s+Stored in directory: ", result.stdout, re.M)

tests/lib/__init__.py

@@ -747,7 +747,7 @@ class PipTestEnvironment(TestFileEnvironment):
             for val in json.loads(ret.stdout)
         }
         expected = {(canonicalize_name(k), v) for k, v in kwargs.items()}
-        assert expected <= installed, "{!r} not all in {!r}".format(expected, installed)
+        assert expected <= installed, f"{expected!r} not all in {installed!r}"
 
     def assert_not_installed(self, *args: str) -> None:
         ret = self.pip("list", "--format=json")
@@ -755,9 +755,7 @@ class PipTestEnvironment(TestFileEnvironment):
         # None of the given names should be listed as installed, i.e. their
         # intersection should be empty.
         expected = {canonicalize_name(k) for k in args}
-        assert not (expected & installed), "{!r} contained in {!r}".format(
-            expected, installed
-        )
+        assert not (expected & installed), f"{expected!r} contained in {installed!r}"
 
 
 # FIXME ScriptTest does something similar, but only within a single
@@ -1028,7 +1026,7 @@ def _create_test_package_with_srcdir(
     pkg_path.joinpath("__init__.py").write_text("")
     subdir_path.joinpath("setup.py").write_text(
         textwrap.dedent(
-            """
+            f"""
                 from setuptools import setup, find_packages
                 setup(
                     name="{name}",
@@ -1036,9 +1034,7 @@ def _create_test_package_with_srcdir(
                     packages=find_packages(),
                     package_dir={{"": "src"}},
                 )
-            """.format(
-                name=name
-            )
+            """
         )
     )
     return _vcs_add(dir_path, version_pkg_path, vcs)
@@ -1052,7 +1048,7 @@ def _create_test_package(
     _create_main_file(version_pkg_path, name=name, output="0.1")
     version_pkg_path.joinpath("setup.py").write_text(
         textwrap.dedent(
-            """
+            f"""
                 from setuptools import setup, find_packages
                 setup(
                     name="{name}",
@@ -1061,9 +1057,7 @@ def _create_test_package(
                     py_modules=["{name}"],
                     entry_points=dict(console_scripts=["{name}={name}:main"]),
                 )
-            """.format(
-                name=name
-            )
+            """
         )
     )
     return _vcs_add(dir_path, version_pkg_path, vcs)
@@ -1137,7 +1131,7 @@ def urlsafe_b64encode_nopad(data: bytes) -> str:
 
 def create_really_basic_wheel(name: str, version: str) -> bytes:
     def digest(contents: bytes) -> str:
-        return "sha256={}".format(urlsafe_b64encode_nopad(sha256(contents).digest()))
+        return f"sha256={urlsafe_b64encode_nopad(sha256(contents).digest())}"
 
     def add_file(path: str, text: str) -> None:
         contents = text.encode("utf-8")
@@ -1153,13 +1147,11 @@ def create_really_basic_wheel(name: str, version: str) -> bytes:
         add_file(
             f"{dist_info}/METADATA",
             dedent(
-                """\
+                f"""\
                 Metadata-Version: 2.1
-                Name: {}
-                Version: {}
-                """.format(
-                    name, version
-                )
+                Name: {name}
+                Version: {version}
+                """
             ),
         )
         z.writestr(record_path, "\n".join(",".join(r) for r in records))

tests/lib/configuration_helpers.py

@@ -38,7 +38,7 @@ class ConfigurationMixin:
             old()
 
         # https://github.com/python/mypy/issues/2427
-        self.configuration._load_config_files = overridden  # type: ignore[assignment]
+        self.configuration._load_config_files = overridden  # type: ignore[method-assign]
 
     @contextlib.contextmanager
     def tmpfile(self, contents: str) -> Iterator[str]:

tests/lib/local_repos.py

@@ -56,7 +56,7 @@ def local_checkout(
         assert vcs_backend is not None
         vcs_backend.obtain(repo_url_path, url=hide_url(remote_repo), verbosity=0)
 
-    return "{}+{}".format(vcs_name, Path(repo_url_path).as_uri())
+    return f"{vcs_name}+{Path(repo_url_path).as_uri()}"
 
 
 def local_repo(remote_repo: str, temp_path: Path) -> str:

tests/lib/server.py

@@ -152,7 +152,7 @@ def html5_page(text: str) -> str:
 
 def package_page(spec: Dict[str, str]) -> "WSGIApplication":
     def link(name: str, value: str) -> str:
-        return '<a href="{}">{}</a>'.format(value, name)
+        return f'<a href="{value}">{name}</a>'
 
     links = "".join(link(*kv) for kv in spec.items())
     return text_html_response(html5_page(links))

tests/lib/test_lib.py

@@ -107,8 +107,8 @@ class TestPipTestEnvironment:
         """
         command = (
             "import logging; logging.basicConfig(level='INFO'); "
-            "logging.getLogger().info('sub: {}', 'foo')"
-        ).format(sub_string)
+            f"logging.getLogger().info('sub: {sub_string}', 'foo')"
+        )
         args = [sys.executable, "-c", command]
         script.run(*args, **kwargs)
 

tests/lib/test_wheel.py

@@ -19,12 +19,12 @@ from tests.lib.wheel import (
 
 def test_message_from_dict_one_value() -> None:
     message = message_from_dict({"a": "1"})
-    assert set(message.get_all("a")) == {"1"}
+    assert set(message.get_all("a")) == {"1"}  # type: ignore
 
 
 def test_message_from_dict_multiple_values() -> None:
     message = message_from_dict({"a": ["1", "2"]})
-    assert set(message.get_all("a")) == {"1", "2"}
+    assert set(message.get_all("a")) == {"1", "2"}  # type: ignore
 
 
 def message_from_bytes(contents: bytes) -> Message:
@@ -67,7 +67,7 @@ def test_make_metadata_file_custom_value_list() -> None:
     f = default_make_metadata(updates={"a": ["1", "2"]})
     assert f is not None
     message = default_metadata_checks(f)
-    assert set(message.get_all("a")) == {"1", "2"}
+    assert set(message.get_all("a")) == {"1", "2"}  # type: ignore
 
 
 def test_make_metadata_file_custom_value_overrides() -> None:
@@ -101,7 +101,7 @@ def default_wheel_metadata_checks(f: File) -> Message:
     assert message.get_all("Wheel-Version") == ["1.0"]
     assert message.get_all("Generator") == ["pip-test-suite"]
     assert message.get_all("Root-Is-Purelib") == ["true"]
-    assert set(message.get_all("Tag")) == {"py2-none-any", "py3-none-any"}
+    assert set(message.get_all("Tag")) == {"py2-none-any", "py3-none-any"}  # type: ignore
     return message
 
 
@@ -122,7 +122,7 @@ def test_make_wheel_metadata_file_custom_value_list() -> None:
     f = default_make_wheel_metadata(updates={"a": ["1", "2"]})
     assert f is not None
     message = default_wheel_metadata_checks(f)
-    assert set(message.get_all("a")) == {"1", "2"}
+    assert set(message.get_all("a")) == {"1", "2"}  # type: ignore
 
 
 def test_make_wheel_metadata_file_custom_value_override() -> None:

tests/lib/wheel.py

@@ -190,7 +190,7 @@ def urlsafe_b64encode_nopad(data: bytes) -> str:
 
 
 def digest(contents: bytes) -> str:
-    return "sha256={}".format(urlsafe_b64encode_nopad(sha256(contents).digest()))
+    return f"sha256={urlsafe_b64encode_nopad(sha256(contents).digest())}"
 
 
 def record_file_maker_wrapper(

tests/unit/metadata/test_metadata.py

@@ -23,7 +23,7 @@ def test_dist_get_direct_url_no_metadata(mock_read_text: mock.Mock) -> None:
     class FakeDistribution(BaseDistribution):
         pass
 
-    dist = FakeDistribution()
+    dist = FakeDistribution()  # type: ignore
     assert dist.direct_url is None
     mock_read_text.assert_called_once_with(DIRECT_URL_METADATA_NAME)
 
@@ -35,7 +35,7 @@ def test_dist_get_direct_url_invalid_json(
     class FakeDistribution(BaseDistribution):
         canonical_name = cast(NormalizedName, "whatever")  # Needed for error logging.
 
-    dist = FakeDistribution()
+    dist = FakeDistribution()  # type: ignore
     with caplog.at_level(logging.WARNING):
         assert dist.direct_url is None
 
@@ -84,7 +84,7 @@ def test_dist_get_direct_url_valid_metadata(mock_read_text: mock.Mock) -> None:
     class FakeDistribution(BaseDistribution):
         pass
 
-    dist = FakeDistribution()
+    dist = FakeDistribution()  # type: ignore
     direct_url = dist.direct_url
     assert direct_url is not None
     mock_read_text.assert_called_once_with(DIRECT_URL_METADATA_NAME)

tests/unit/test_base_command.py

@@ -151,7 +151,7 @@ def test_base_command_provides_tempdir_helpers() -> None:
 
     c = Command("fake", "fake")
     # https://github.com/python/mypy/issues/2427
-    c.run = Mock(side_effect=assert_helpers_set)  # type: ignore[assignment]
+    c.run = Mock(side_effect=assert_helpers_set)  # type: ignore[method-assign]
     assert c.main(["fake"]) == SUCCESS
     c.run.assert_called_once()
 
@@ -176,7 +176,7 @@ def test_base_command_global_tempdir_cleanup(kind: str, exists: bool) -> None:
 
     c = Command("fake", "fake")
     # https://github.com/python/mypy/issues/2427
-    c.run = Mock(side_effect=create_temp_dirs)  # type: ignore[assignment]
+    c.run = Mock(side_effect=create_temp_dirs)  # type: ignore[method-assign]
     assert c.main(["fake"]) == SUCCESS
     c.run.assert_called_once()
     assert os.path.exists(Holder.value) == exists
@@ -200,6 +200,6 @@ def test_base_command_local_tempdir_cleanup(kind: str, exists: bool) -> None:
 
     c = Command("fake", "fake")
     # https://github.com/python/mypy/issues/2427
-    c.run = Mock(side_effect=create_temp_dirs)  # type: ignore[assignment]
+    c.run = Mock(side_effect=create_temp_dirs)  # type: ignore[method-assign]
     assert c.main(["fake"]) == SUCCESS
     c.run.assert_called_once()

tests/unit/test_collector.py

@@ -119,8 +119,8 @@ def test_get_index_content_invalid_content_type_archive(
     assert (
         "pip._internal.index.collector",
         logging.WARNING,
-        "Skipping page {} because it looks like an archive, and cannot "
-        "be checked by a HTTP HEAD request.".format(url),
+        f"Skipping page {url} because it looks like an archive, and cannot "
+        "be checked by a HTTP HEAD request.",
     ) in caplog.record_tuples
 
 
@@ -417,8 +417,8 @@ def _test_parse_links_data_attribute(
     html = (
         "<!DOCTYPE html>"
         '<html><head><meta charset="utf-8"><head>'
-        "<body>{}</body></html>"
-    ).format(anchor_html)
+        f"<body>{anchor_html}</body></html>"
+    )
     html_bytes = html.encode("utf-8")
     page = IndexContent(
         html_bytes,
@@ -764,8 +764,8 @@ def test_get_index_content_invalid_scheme(
         (
             "pip._internal.index.collector",
             logging.WARNING,
-            "Cannot look at {} URL {} because it does not support "
-            "lookup as web pages.".format(vcs_scheme, url),
+            f"Cannot look at {vcs_scheme} URL {url} because it does not support "
+            "lookup as web pages.",
         ),
     ]
 

tests/unit/test_configuration.py

@@ -215,7 +215,7 @@ class TestConfigurationModification(ConfigurationMixin):
         # Mock out the method
         mymock = MagicMock(spec=self.configuration._mark_as_modified)
         # https://github.com/python/mypy/issues/2427
-        self.configuration._mark_as_modified = mymock  # type: ignore[assignment]
+        self.configuration._mark_as_modified = mymock  # type: ignore[method-assign]
 
         self.configuration.set_value("test.hello", "10")
 
@@ -231,7 +231,7 @@ class TestConfigurationModification(ConfigurationMixin):
         # Mock out the method
         mymock = MagicMock(spec=self.configuration._mark_as_modified)
         # https://github.com/python/mypy/issues/2427
-        self.configuration._mark_as_modified = mymock  # type: ignore[assignment]
+        self.configuration._mark_as_modified = mymock  # type: ignore[method-assign]
 
         self.configuration.set_value("test.hello", "10")
 
@@ -250,7 +250,7 @@ class TestConfigurationModification(ConfigurationMixin):
         # Mock out the method
         mymock = MagicMock(spec=self.configuration._mark_as_modified)
         # https://github.com/python/mypy/issues/2427
-        self.configuration._mark_as_modified = mymock  # type: ignore[assignment]
+        self.configuration._mark_as_modified = mymock  # type: ignore[method-assign]
 
         self.configuration.set_value("test.hello", "10")
 

tests/unit/test_link.py

@@ -143,10 +143,7 @@ class TestLink:
     def test_is_hash_allowed(
         self, hash_name: str, hex_digest: str, expected: bool
     ) -> None:
-        url = "https://example.com/wheel.whl#{hash_name}={hex_digest}".format(
-            hash_name=hash_name,
-            hex_digest=hex_digest,
-        )
+        url = f"https://example.com/wheel.whl#{hash_name}={hex_digest}"
         link = Link(url)
         hashes_data = {
             "sha512": [128 * "a", 128 * "b"],

tests/unit/test_network_utils.py

@@ -21,8 +21,8 @@ def test_raise_for_status_raises_exception(status_code: int, error_type: str) ->
     with pytest.raises(NetworkConnectionError) as excinfo:
         raise_for_status(resp)
     assert str(excinfo.value) == (
-        "{} {}: Network Error for url:"
-        " http://www.example.com/whatever.tgz".format(status_code, error_type)
+        f"{status_code} {error_type}: Network Error for url:"
+        " http://www.example.com/whatever.tgz"
     )
 
 

tests/unit/test_req.py

@@ -235,8 +235,8 @@ class TestRequirementSet:
                     r"file \(line 1\)\)\n"
                     r"Can't verify hashes for these file:// requirements because "
                     r"they point to directories:\n"
-                    r"    file://.*{sep}data{sep}packages{sep}FSPkg "
-                    r"\(from -r file \(line 2\)\)".format(sep=sep)
+                    rf"    file://.*{sep}data{sep}packages{sep}FSPkg "
+                    r"\(from -r file \(line 2\)\)"
                 ),
             ):
                 resolver.resolve(reqset.all_requirements, True)

tests/unit/test_req_file.py

@@ -297,7 +297,7 @@ class TestProcessLine:
     def test_yield_line_constraint(self, line_processor: LineProcessor) -> None:
         line = "SomeProject"
         filename = "filename"
-        comes_from = "-c {} (line {})".format(filename, 1)
+        comes_from = f"-c {filename} (line {1})"
         req = install_req_from_line(line, comes_from=comes_from, constraint=True)
         found_req = line_processor(line, filename, 1, constraint=True)[0]
         assert repr(found_req) == repr(req)
@@ -326,7 +326,7 @@ class TestProcessLine:
         url = "git+https://url#egg=SomeProject"
         line = f"-e {url}"
         filename = "filename"
-        comes_from = "-c {} (line {})".format(filename, 1)
+        comes_from = f"-c {filename} (line {1})"
         req = install_req_from_editable(url, comes_from=comes_from, constraint=True)
         found_req = line_processor(line, filename, 1, constraint=True)[0]
         assert repr(found_req) == repr(req)
@@ -873,12 +873,10 @@ class TestParseRequirements:
     ) -> None:
         global_option = "--dry-run"
 
-        content = """
+        content = f"""
         --only-binary :all:
         INITools==2.0 --global-option="{global_option}"
-        """.format(
-            global_option=global_option
-        )
+        """
 
         with requirements_file(content, tmpdir) as reqs_file:
             req = next(

tests/unit/test_resolution_legacy_resolver.py

@@ -252,7 +252,7 @@ class TestCheckDistRequiresPython:
             def metadata(self) -> email.message.Message:
                 raise FileNotFoundError(metadata_name)
 
-        dist = make_fake_dist(klass=NotWorkingFakeDist)
+        dist = make_fake_dist(klass=NotWorkingFakeDist)  # type: ignore
 
         with pytest.raises(NoneMetadataError) as exc:
             _check_dist_requires_python(
@@ -261,8 +261,8 @@ class TestCheckDistRequiresPython:
                 ignore_requires_python=False,
             )
         assert str(exc.value) == (
-            "None {} metadata found for distribution: "
-            "<distribution 'my-project'>".format(metadata_name)
+            f"None {metadata_name} metadata found for distribution: "
+            "<distribution 'my-project'>"
         )
 
 

tests/unit/test_vcs.py

@@ -66,7 +66,7 @@ def test_rev_options_repr() -> None:
         # First check VCS-specific RevOptions behavior.
         (Bazaar, [], ["-r", "123"], {}),
         (Git, ["HEAD"], ["123"], {}),
-        (Mercurial, [], ["-r=123"], {}),
+        (Mercurial, [], ["--rev=123"], {}),
         (Subversion, [], ["-r", "123"], {}),
         # Test extra_args.  For this, test using a single VersionControl class.
         (

tests/unit/test_wheel.py

@@ -102,15 +102,13 @@ def test_get_legacy_build_wheel_path__multiple_names(
     ],
 )
 def test_get_entrypoints(tmp_path: pathlib.Path, console_scripts: str) -> None:
-    entry_points_text = """
+    entry_points_text = f"""
         [console_scripts]
-        {}
+        {console_scripts}
         [section]
         common:one = module:func
         common:two = module:other_func
-    """.format(
-        console_scripts
-    )
+    """
 
     distribution = make_wheel(
         "simple",

tools/release/check_version.py

@@ -27,7 +27,7 @@ def is_this_a_good_version_number(string: str) -> Optional[str]:
     expected_major = datetime.now().year % 100
 
     if len(release) not in [2, 3]:
-        return "Not of the form: {0}.N or {0}.N.P".format(expected_major)
+        return f"Not of the form: {expected_major}.N or {expected_major}.N.P"
 
     return None