Fix get_versioned_files() failing when GIT_INDEX_FILE is set

CHANGES.rst

@@ -5,7 +5,11 @@ Changelog
 0.43 (unreleased)
 -----------------
 
-- Nothing changed yet.
+- Fix collecting files versioned by ``git`` when a project has submodules and
+  ``GIT_INDEX_FILE`` is set.  This bug was triggered when ``check-manifest``
+  was run as part of a git hook (
+  `#122 <https://github.com/mgedmin/check-manifest/issues/122>`__,
+  `#123 <https://github.com/mgedmin/check-manifest/pull/123>`__).
 
 
 0.42 (2020-05-03)

check_manifest.py

@@ -369,16 +369,6 @@ def strip_toplevel_name(filelist):
     return [name[len(prefix):] for name in names if name != prefix]
 
 
-def add_prefix_to_each(prefix, filelist):
-    """Add a prefix to each name in a file list.
-
-        >>> add_prefix_to_each('foo/bar', ['a', 'b', 'c/d'])
-        ['foo/bar/a', 'foo/bar/b', 'foo/bar/c/d']
-
-    """
-    return [posixpath.join(prefix, name) for name in filelist]
-
-
 class VCS:
 
     def __init__(self, ui):
@@ -406,33 +396,14 @@ def detect(cls, location):
 
     def get_versioned_files(self):
         """List all files versioned by git in the current directory."""
-        files = self._git_ls_files()
-        submodules = self._list_submodules()
-        for subdir in submodules:
-            subdir = os.path.relpath(subdir).replace(os.path.sep, '/')
-            files += add_prefix_to_each(subdir, self._git_ls_files(subdir))
-        return files
-
-    @classmethod
-    def _git_ls_files(cls, cwd=None):
-        output = run(['git', 'ls-files', '-z'], encoding=cls._encoding, cwd=cwd)
+        output = run(
+            ["git", "ls-files", "-z", "--recurse-submodules"],
+            encoding=self._encoding,
+        )
         # -z tells git to use \0 as a line terminator; split() treats it as a
         # line separator, so we always get one empty line at the end, which we
         # drop with the [:-1] slice
-        return output.split('\0')[:-1]
-
-    @classmethod
-    def _list_submodules(cls):
-        # This is incredibly expensive on my Jenkins instance (50 seconds for
-        # each invocation, even when there are no submodules whatsoever).
-        # Curiously, I cannot reproduce that in Appveyor, or even on the same
-        # Jenkins machine but when I run the tests manually.  Still, 2-hour
-        # Jenkins runs are bad, so let's avoid running 'git submodule' when
-        # there's no .gitmodules file.
-        if not os.path.exists('.gitmodules'):
-            return []
-        return run(['git', 'submodule', '--quiet', 'foreach', '--recursive',
-                    'printf "%s/%s\\n" $toplevel $path'], encoding=cls._encoding).splitlines()
+        return output.split("\0")[:-1]
 
 
 class Mercurial(VCS):

tests.py

@@ -1102,6 +1102,10 @@ def test_get_versioned_files_with_git_submodules(self):
                 'subdir/sub2/sub3/file4',
             ])
 
+    def test_get_versioned_files_with_git_submodules_with_git_index_file_set(self):
+        with mock.patch.dict(os.environ, {"GIT_INDEX_FILE": ".git/index"}):
+            self.test_get_versioned_files_with_git_submodules()
+
 
 class BzrHelper(VCSHelper):