Check gitignore more intelligently

Author: ucodery

isort/settings.py

@@ -552,11 +552,10 @@ def _check_folder_gitignore(self, folder: str) -> Optional[Path]:
         # don't check symlinks; either part of the repo and would be checked
         # twice, or is external to the repo and git won't konw anything about it
         for root, _dirs, git_files in os.walk(git_folder, followlinks=False):
+            if ".git" in _dirs:
+                _dirs.remove(".git")
             for git_file in git_files:
-                git_path = os.path.join(root, git_file)
-                # followlinks only disables walking into linked dirs
-                if not os.path.islink(git_path):
-                    files.append(git_path)
+                files.append(os.path.join(root, git_file))
         git_options = ["-C", str(git_folder), "-c", "core.quotePath="]
         try:
             ignored = subprocess.check_output(  # nosec # skipcq: PYL-W1510

tests/unit/test_isort.py

@@ -2708,7 +2708,7 @@ def test_import_by_paren_issue_375() -> None:
 
 
 def test_import_by_paren_issue_460() -> None:
-    """Test to ensure isort can doesnt move comments around """
+    """Test to ensure isort can doesnt move comments around"""
     test_input = """
 # First comment
 # Second comment
@@ -5184,7 +5184,7 @@ def test_only_sections() -> None:
 
 
 def test_combine_straight_imports() -> None:
-    """ Tests to ensure that combine_straight_imports works correctly """
+    """Tests to ensure that combine_straight_imports works correctly"""
 
     test_input = (
         "import os\n" "import sys\n" "# this is a comment\n" "import math  # inline comment\n"

tests/unit/test_main.py

@@ -1170,3 +1170,26 @@ def main_check(args):
     out, error = main_check([str(tmpdir), "--skip-gitignore", "--filter-files"])
 
     assert all(f"{str(tmpdir)}{file}" in out for file in should_check)
+
+    # Should work when git project contains symlinks
+
+    if os.name != "nt":
+        git_project0.join("has_imports_ignored.py").write(import_content)
+        git_project0.join("has_imports.py").write(import_content)
+        tmpdir.join("has_imports.py").write(import_content)
+        tmpdir.join("nested_dir").join("has_imports.py").write(import_content)
+        git_project0.join("ignore_link.py").mksymlinkto(tmpdir.join("has_imports.py"))
+        git_project0.join("ignore_link").mksymlinkto(tmpdir.join("nested_dir"))
+        git_project0.join(".gitignore").write("ignore_link.py\nignore_link", mode="a")
+
+        out, error = main_check(
+            [str(git_project0), "--skip-gitignore", "--filter-files", "--check"]
+        )
+
+        should_check = ["/git_project0/has_imports.py"]
+
+        assert all(f"{str(tmpdir)}{file}" in error for file in should_check)
+
+        out, error = main_check([str(git_project0), "--skip-gitignore", "--filter-files"])
+
+        assert all(f"{str(tmpdir)}{file}" in out for file in should_check)