Do not use gitignore if explicitly passing excludes

CHANGES.md

@@ -22,6 +22,9 @@
   [circumstances](https://github.com/psf/black/blob/master/docs/the_black_code_style.md#pragmatism)
   in which _Black_ may change the AST (#2159)
 
+- Allow `.gitignore` rules to be overridden by specifying `exclude` in `pyproject.toml`
+  or on the command line. (#2170)
+
 #### _Packaging_
 
 - Install `primer.json` (used by `black-primer` by default) with black. (#2154)

src/black/__init__.py

@@ -492,15 +492,15 @@ def validate_regex(
 @click.option(
     "--exclude",
     type=str,
-    default=DEFAULT_EXCLUDES,
     callback=validate_regex,
     help=(
         "A regular expression that matches files and directories that should be"
         " excluded on recursive searches. An empty value means no paths are excluded."
         " Use forward slashes for directories on all platforms (Windows, too)."
-        " Exclusions are calculated first, inclusions later."
+        " Exclusions are calculated first, inclusions later. [default:"
+        f" {DEFAULT_EXCLUDES}]"
     ),
-    show_default=True,
+    show_default=False,
 )
 @click.option(
     "--extend-exclude",
@@ -587,7 +587,7 @@ def main(
     quiet: bool,
     verbose: bool,
     include: Pattern,
-    exclude: Pattern,
+    exclude: Optional[Pattern],
     extend_exclude: Optional[Pattern],
     force_exclude: Optional[Pattern],
     stdin_filename: Optional[str],
@@ -662,7 +662,7 @@ def get_sources(
     quiet: bool,
     verbose: bool,
     include: Pattern[str],
-    exclude: Pattern[str],
+    exclude: Optional[Pattern[str]],
     extend_exclude: Optional[Pattern[str]],
     force_exclude: Optional[Pattern[str]],
     report: "Report",
@@ -673,7 +673,12 @@ def get_sources(
     root = find_project_root(src)
     sources: Set[Path] = set()
     path_empty(src, "No Path provided. Nothing to do 😴", quiet, verbose, ctx)
-    gitignore = get_gitignore(root)
+
+    if exclude is None:
+        exclude = re_compile_maybe_verbose(DEFAULT_EXCLUDES)
+        gitignore = get_gitignore(root)
+    else:
+        gitignore = None
 
     for s in src:
         if s == "-" and stdin_filename:
@@ -6215,12 +6220,12 @@ def path_is_excluded(
 def gen_python_files(
     paths: Iterable[Path],
     root: Path,
-    include: Optional[Pattern[str]],
+    include: Pattern[str],
     exclude: Pattern[str],
     extend_exclude: Optional[Pattern[str]],
     force_exclude: Optional[Pattern[str]],
     report: "Report",
-    gitignore: PathSpec,
+    gitignore: Optional[PathSpec],
 ) -> Iterator[Path]:
     """Generate all files under `path` whose paths are not excluded by the
     `exclude_regex`, `extend_exclude`, or `force_exclude` regexes,
@@ -6236,8 +6241,8 @@ def gen_python_files(
         if normalized_path is None:
             continue
 
-        # First ignore files matching .gitignore
-        if gitignore.match_file(normalized_path):
+        # First ignore files matching .gitignore, if passed
+        if gitignore is not None and gitignore.match_file(normalized_path):
             report.path_ignored(child, "matches the .gitignore file content")
             continue
 

tests/data/include_exclude_tests/.gitignore

@@ -0,0 +1 @@
+dont_exclude/

tests/data/include_exclude_tests/pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools>=41.0", "setuptools-scm", "wheel"]
+build-backend = "setuptools.build_meta"

tests/test_black.py

@@ -1418,6 +1418,32 @@ def test_include_exclude(self) -> None:
         )
         self.assertEqual(sorted(expected), sorted(sources))
 
+    def test_gitingore_used_as_default(self) -> None:
+        path = Path(THIS_DIR / "data" / "include_exclude_tests")
+        include = re.compile(r"\.pyi?$")
+        extend_exclude = re.compile(r"/exclude/")
+        src = str(path / "b/")
+        report = black.Report()
+        expected: List[Path] = [
+            path / "b/.definitely_exclude/a.py",
+            path / "b/.definitely_exclude/a.pyi",
+        ]
+        sources = list(
+            black.get_sources(
+                ctx=FakeContext(),
+                src=(src,),
+                quiet=True,
+                verbose=False,
+                include=include,
+                exclude=None,
+                extend_exclude=extend_exclude,
+                force_exclude=None,
+                report=report,
+                stdin_filename=None,
+            )
+        )
+        self.assertEqual(sorted(expected), sorted(sources))
+
     @patch("black.find_project_root", lambda *args: THIS_DIR.resolve())
     def test_exclude_for_issue_1572(self) -> None:
         # Exclude shouldn't touch files that were explicitly given to Black through the
@@ -1705,6 +1731,8 @@ def test_empty_include(self) -> None:
             Path(path / "b/.definitely_exclude/a.pie"),
             Path(path / "b/.definitely_exclude/a.py"),
             Path(path / "b/.definitely_exclude/a.pyi"),
+            Path(path / ".gitignore"),
+            Path(path / "pyproject.toml"),
         ]
         this_abs = THIS_DIR.resolve()
         sources.extend(