Check excludes before symlink resolution for command line parameters

CHANGES.md

@@ -18,7 +18,8 @@
 ### Configuration
 
 - Add support for single line format skip with other comments on the same line (#3959)
-
+- File exclusion and inclusion logic is now consistently applied before symlink
+  resolution. (#3987) (#3976)
 - Fix a bug in the matching of absolute path names in `--include` (#3976)
 
 ### Packaging

src/black/__init__.py

@@ -50,6 +50,7 @@
     get_gitignore,
     normalize_path_maybe_ignore,
     parse_pyproject_toml,
+    path_is_excluded,
     wrap_stream_for_windows,
 )
 from black.handle_ipynb_magics import (
@@ -639,25 +640,26 @@ def get_sources(
             is_stdin = False
 
         if is_stdin or p.is_file():
+            root_relative_path = p.absolute().relative_to(root).as_posix()
+
+            root_relative_path = "/" + root_relative_path
+            if p.is_dir():
+                root_relative_path += "/"
+
+            # Hard-exclude any files that matches the `--force-exclude` regex.
+            if path_is_excluded(root_relative_path, force_exclude):
+                report.path_ignored(p, "matches the --force-exclude regular expression")
+                continue
+
             normalized_path: Optional[str] = normalize_path_maybe_ignore(
                 p, root, report
             )
             if normalized_path is None:
                 if verbose:
-                    out(f'Skipping invalid source: "{normalized_path}"', fg="red")
+                    out(f'Skipping invalid source: "{p}"', fg="red")
                 continue
             if verbose:
-                out(f'Found input source: "{normalized_path}"', fg="blue")
-
-            normalized_path = "/" + normalized_path
-            # Hard-exclude any files that matches the `--force-exclude` regex.
-            if force_exclude:
-                force_exclude_match = force_exclude.search(normalized_path)
-            else:
-                force_exclude_match = None
-            if force_exclude_match and force_exclude_match.group(0):
-                report.path_ignored(p, "matches the --force-exclude regular expression")
-                continue
+                out(f'Found input source: "{p}"', fg="blue")
 
             if is_stdin:
                 p = Path(f"{STDIN_PLACEHOLDER}{str(p)}")

tests/test_black.py

@@ -1409,6 +1409,24 @@ def test_invalid_cli_regex(self) -> None:
         for option in ["--include", "--exclude", "--extend-exclude", "--force-exclude"]:
             self.invokeBlack(["-", option, "**()(!!*)"], exit_code=2)
 
+    def test_force_exclude_symlink_parameter(self) -> None:
+        with TemporaryDirectory() as workspace:
+            root = Path(workspace)
+            (root / "pyproject.toml").touch()
+
+            symlink_target = root / "target.py"
+            symlink_target.write_text("print ( )\n", encoding="utf-8")
+
+            symlink = root / "symlink.py"
+            symlink.symlink_to(symlink_target)
+
+            # target.py would need to be reformatted, and symlink.py points to
+            # it, but since we force-exclude symlink.py, black should not check
+            # the pointed-to file.
+            self.invokeBlack(
+                ["--check", r"--force-exclude=sym", str(symlink)], exit_code=0
+            )
+
     def test_required_version_matches_version(self) -> None:
         self.invokeBlack(
             ["--required-version", black.__version__, "-c", "0"],