Enable following symbolic links when traversing a directory

babel/messages/extract.py

@@ -160,6 +160,7 @@ def extract_from_dir(
     callback: Callable[[str, str, dict[str, Any]], object] | None = None,
     strip_comment_tags: bool = False,
     directory_filter: Callable[[str], bool] | None = None,
+    follow_links: bool = False,
 ) -> Generator[_FileExtractionResult, None, None]:
     """Extract messages from any source files found in the given directory.
 
@@ -228,6 +229,8 @@ def extract_from_dir(
     :param directory_filter: a callback to determine whether a directory should
                              be recursed into. Receives the full directory path;
                              should return True if the directory is valid.
+    :param follow_links: whether to follow symbolic links to directories. Links
+                         that form a cycle are followed indefinitely.
     :see: `pathmatch`
     """
     if dirname is None:
@@ -244,7 +247,7 @@ def extract_from_dir(
             root_dir=dirname,
         )
 
-    for root, dirnames, filenames in os.walk(dirname):
+    for root, dirnames, filenames in os.walk(dirname, followlinks=follow_links):
         dirnames[:] = [
             subdir for subdir in dirnames if directory_filter(os.path.join(root, subdir))
         ]

babel/messages/frontend.py

@@ -355,6 +355,8 @@ class ExtractMessages(CommandMixin):
          'header comment for the catalog'),
         ('last-translator=', None,
          'set the name and email of the last translator in output'),
+        ('follow-links', None,
+         'follow symbolic links when traversing directories'),
     ]  # fmt: skip
     boolean_options = [
         'no-default-keywords',
@@ -364,6 +366,7 @@ class ExtractMessages(CommandMixin):
         'sort-output',
         'sort-by-file',
         'strip-comments',
+        'follow-links',
     ]
     as_args = 'input-paths'
     multiple_value_options = (
@@ -403,6 +406,7 @@ def initialize_options(self):
         self.version = None
         self.add_comments = None
         self.strip_comments = False
+        self.follow_links = False
         self.include_lineno = True
         self.ignore_dirs = None
         self.header_comment = None
@@ -532,6 +536,7 @@ def run(self):
                         directory_filter=self.directory_filter,
                         keywords=self.keywords,
                         strip_comment_tags=self.strip_comments,
+                        follow_links=self.follow_links,
                     )
                 for filename, lineno, message, comments, context in extracted:
                     if os.path.isfile(path):

docs/cmdline.rst

@@ -131,6 +131,7 @@ a collection of source files::
                             (default ".* ._")
       --header-comment=HEADER_COMMENT
                             header comment for the catalog
+      --follow-links        follow symbolic links when traversing directories
 
 
 The meaning of ``--keyword`` values is as follows:

tests/messages/frontend/test_frontend.py

@@ -317,6 +317,12 @@ def test_extract_cli_knows_dash_s():
     assert cmdinst.strip_comments
 
 
+def test_extract_cli_knows_follow_links():
+    cmdinst = configure_cli_command("extract --follow-links -o foo babel")
+    assert isinstance(cmdinst, ExtractMessages)
+    assert cmdinst.follow_links
+
+
 def test_extract_cli_knows_dash_dash_last_dash_translator():
     cmdinst = configure_cli_command('extract --last-translator "FULL NAME EMAIL@ADDRESS" -o foo babel')
     assert isinstance(cmdinst, ExtractMessages)

tests/messages/test_extract.py

@@ -10,6 +10,7 @@
 # individuals. For the exact contribution history, see the revision
 # history and logs, available at https://github.com/python-babel/babel/commits/master/.
 
+import os
 import sys
 from io import BytesIO, StringIO
 
@@ -174,3 +175,22 @@ def test_issue_1195_2():
         'NOTE: This should still be considered, even if',
         'the text is far away',
     ]
+
+
+@pytest.mark.skipif(not hasattr(os, 'symlink'), reason='requires symlink support')
+@pytest.mark.parametrize('follow_links', [False, True])
+def test_extract_from_dir_follow_links(tmp_path, follow_links):
+    target = tmp_path / 'target'
+    target.mkdir()
+    (target / 'linked.py').write_text('_("linked")')
+    project = tmp_path / 'project'
+    project.mkdir()
+    (project / 'plain.py').write_text('_("plain")')
+    try:
+        (project / 'link').symlink_to(target, target_is_directory=True)
+    except OSError:
+        pytest.skip('cannot create symlinks')
+
+    results = extract.extract_from_dir(project, follow_links=follow_links)
+    messages = {message for _, _, message, _, _ in results}
+    assert messages == ({'plain', 'linked'} if follow_links else {'plain'})