PEP 427 mandates UTF-8, we don't need the fallback

news/8684.bugfix

@@ -1,2 +1,2 @@
-Use the same encoding logic from Python 3 to handle ZIP archive entries on
-Python 2, so non-ASCII paths can be resolved as expected.
+Use UTF-8 to handle ZIP archive entries on Python 2 according to PEP 427, so
+non-ASCII paths can be resolved as expected.

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

@@ -425,23 +425,10 @@ class ZipBackedFile(object):
         # type: () -> ZipInfo
         if not PY2:
             return self._zip_file.getinfo(self.src_record_path)
-
-        # Python 2 does not expose a way to detect a ZIP's encoding, so we
-        # "guess" with the heuristics below:
-        # 1. Try encoding the path with UTF-8.
-        # 2. Check the matching info's flags for language encoding (bit 11).
-        # 3. If the flag is set, assume UTF-8 is correct.
-        # 4. If any of the above steps fails, fallback to getting an info with
-        #    CP437 (matching Python 3).
-        try:
-            arcname = self.src_record_path.encode("utf-8")
-            info = self._zip_file.getinfo(arcname)
-            if info.flag_bits & 0x800:
-                return info
-        except (KeyError, UnicodeEncodeError):
-            pass
-        arcname = self.src_record_path.encode("cp437")
-        return self._zip_file.getinfo(arcname)
+        # Python 2 does not expose a way to detect a ZIP's encoding, but the
+        # wheel specification (PEP 427) explicitly mandates that paths should
+        # use UTF-8, so we assume it is true.
+        return self._zip_file.getinfo(self.src_record_path.encode("utf-8"))
 
     def save(self):
         # type: () -> None