Change get_revision_sha() to return is_branch.

src/pip/_internal/vcs/git.py

@@ -105,8 +105,8 @@ class Git(VersionControl):
 
     def get_revision_sha(self, dest, rev):
         """
-        Return a commit hash for the given revision if it names a remote
-        branch or tag.  Otherwise, return None.
+        Return (sha_or_none, is_branch), where sha_or_none is a commit hash
+        if the revision names a remote branch or tag, otherwise None.
 
         Args:
           dest: the repository directory.
@@ -129,7 +129,13 @@ class Git(VersionControl):
         branch_ref = 'refs/remotes/origin/{}'.format(rev)
         tag_ref = 'refs/tags/{}'.format(rev)
 
-        return refs.get(branch_ref) or refs.get(tag_ref)
+        sha = refs.get(branch_ref)
+        if sha is not None:
+            return (sha, True)
+
+        sha = refs.get(tag_ref)
+
+        return (sha, False)
 
     def resolve_revision(self, dest, url, rev_options):
         """
@@ -140,7 +146,7 @@ class Git(VersionControl):
           rev_options: a RevOptions object.
         """
         rev = rev_options.arg_rev
-        sha = self.get_revision_sha(dest, rev)
+        sha, is_branch = self.get_revision_sha(dest, rev)
 
         if sha is not None:
             return rev_options.make_new(sha)

tests/functional/test_vcs_git.py

@@ -37,9 +37,9 @@ def add_commits(script, dest, count):
     return shas
 
 
-def check_rev(repo_dir, rev, expected_sha):
+def check_rev(repo_dir, rev, expected):
     git = Git()
-    assert git.get_revision_sha(repo_dir, rev) == expected_sha
+    assert git.get_revision_sha(repo_dir, rev) == expected
 
 
 def test_git_dir_ignored():
@@ -123,9 +123,9 @@ def test_get_revision_sha(script):
         script.run('git', 'tag', 'aaa/v1.0', head_sha, cwd=repo_dir)
         script.run('git', 'tag', 'zzz/v1.0', head_sha, cwd=repo_dir)
 
-        check_rev(repo_dir, 'v1.0', tag_sha)
-        check_rev(repo_dir, 'v2.0', tag_sha)
-        check_rev(repo_dir, 'origin-branch', origin_sha)
+        check_rev(repo_dir, 'v1.0', (tag_sha, False))
+        check_rev(repo_dir, 'v2.0', (tag_sha, False))
+        check_rev(repo_dir, 'origin-branch', (origin_sha, True))
 
         ignored_names = [
             # Local branches should be ignored.
@@ -143,7 +143,7 @@ def test_get_revision_sha(script):
             'does-not-exist',
         ]
         for name in ignored_names:
-            check_rev(repo_dir, name, None)
+            check_rev(repo_dir, name, (None, False))
 
 
 @pytest.mark.network

tests/unit/test_vcs.py

@@ -109,7 +109,7 @@ def test_git_get_src_requirements(git, dist):
 
 @patch('pip._internal.vcs.git.Git.get_revision_sha')
 def test_git_resolve_revision_rev_exists(get_sha_mock):
-    get_sha_mock.return_value = '123456'
+    get_sha_mock.return_value = ('123456', False)
     git = Git()
     rev_options = git.make_rev_options('develop')
 
@@ -120,7 +120,7 @@ def test_git_resolve_revision_rev_exists(get_sha_mock):
 
 @patch('pip._internal.vcs.git.Git.get_revision_sha')
 def test_git_resolve_revision_rev_not_found(get_sha_mock):
-    get_sha_mock.return_value = None
+    get_sha_mock.return_value = (None, False)
     git = Git()
     rev_options = git.make_rev_options('develop')
 
@@ -131,7 +131,7 @@ def test_git_resolve_revision_rev_not_found(get_sha_mock):
 
 @patch('pip._internal.vcs.git.Git.get_revision_sha')
 def test_git_resolve_revision_not_found_warning(get_sha_mock, caplog):
-    get_sha_mock.return_value = None
+    get_sha_mock.return_value = (None, False)
     git = Git()
 
     url = 'git+https://git.example.com'