Support --exclude more than once on command line

The result is an "OR" of all the patterns provided.
Should be fully backward compatible to existing folks.

Fixes python#10310

Author: nipunn1313

docs/source/command_line.rst

@@ -59,8 +59,8 @@ for full details, see :ref:`running-mypy`.
     pass ``--exclude '/setup\.py$'``. Similarly, you can ignore discovering
     directories with a given name by e.g. ``--exclude /build/`` or
     those matching a subpath with ``--exclude /project/vendor/``. To ignore
-    multiple files / directories / paths, you can combine expressions with
-    ``|``, e.g ``--exclude '/setup\.py$|/build/'``.
+    multiple files / directories / paths, you can provide the --exclude
+    flag more than once, e.g ``--exclude '/setup\.py$' --exclude '/build/'``.
 
     Note that this flag only affects recursive directory tree discovery, that
     is, when mypy is discovering files within a directory tree or submodules of

docs/source/config_file.rst

@@ -201,7 +201,7 @@ section of the command line docs.
 
     A regular expression that matches file names, directory names and paths
     which mypy should ignore while recursively discovering files to check.
-    Use forward slashes on all platforms.
+    Use forward slashes on all platforms. May be specified more than once.
 
     For more details, see :option:`--exclude <mypy --exclude>`.
 

mypy/main.py

@@ -864,11 +864,13 @@ def add_invertible_flag(flag: str,
         group=code_group)
     code_group.add_argument(
         "--exclude",
+        action="append",
         metavar="PATTERN",
-        default="",
+        default=[],
         help=(
             "Regular expression to match file names, directory names or paths which mypy should "
-            "ignore while recursively discovering files to check, e.g. --exclude '/setup\\.py$'"
+            "ignore while recursively discovering files to check, e.g. --exclude '/setup\\.py$'. "
+            "May be specified more than once, eg. --exclude a --exclude b"
         )
     )
     code_group.add_argument(

mypy/modulefinder.py

@@ -500,16 +500,21 @@ def find_modules_recursive(self, module: str) -> List[BuildSource]:
         return sources
 
 
-def matches_exclude(subpath: str, exclude: str, fscache: FileSystemCache, verbose: bool) -> bool:
-    if not exclude:
+def matches_exclude(subpath: str,
+                    excludes: List[str],
+                    fscache: FileSystemCache,
+                    verbose: bool) -> bool:
+    if not excludes:
         return False
     subpath_str = os.path.relpath(subpath).replace(os.sep, "/")
     if fscache.isdir(subpath):
         subpath_str += "/"
-    if re.search(exclude, subpath_str):
-        if verbose:
-            print("TRACE: Excluding {}".format(subpath_str), file=sys.stderr)
-        return True
+    for exclude in excludes:
+        if re.search(exclude, subpath_str):
+            if verbose:
+                print("TRACE: Excluding {} (matches pattern {})".format(subpath_str, exclude),
+                      file=sys.stderr)
+            return True
     return False
 
 

mypy/options.py

@@ -100,7 +100,7 @@ def __init__(self) -> None:
         # top-level __init__.py to your packages.
         self.explicit_package_bases = False
         # File names, directory names or subpaths to avoid checking
-        self.exclude: str = ""
+        self.exclude: List[str] = []
 
         # disallow_any options
         self.disallow_any_generics = False

mypy/test/test_find_sources.py

@@ -298,7 +298,7 @@ def test_find_sources_exclude(self) -> None:
         }
 
         # file name
-        options.exclude = r"/f\.py$"
+        options.exclude = [r"/f\.py$"]
         fscache = FakeFSCache(files)
         assert find_sources(["/"], options, fscache) == [
             ("a2", "/pkg"),
@@ -309,7 +309,7 @@ def test_find_sources_exclude(self) -> None:
         assert find_sources(["/pkg/a2/b/f.py"], options, fscache) == [('a2.b.f', '/pkg')]
 
         # directory name
-        options.exclude = "/a1/"
+        options.exclude = ["/a1/"]
         fscache = FakeFSCache(files)
         assert find_sources(["/"], options, fscache) == [
             ("a2", "/pkg"),
@@ -323,13 +323,13 @@ def test_find_sources_exclude(self) -> None:
         with pytest.raises(InvalidSourceList):
             find_sources(["/pkg/a1/b"], options, fscache)
 
-        options.exclude = "/a1/$"
+        options.exclude = ["/a1/$"]
         assert find_sources(["/pkg/a1"], options, fscache) == [
             ('e', '/pkg/a1/b/c/d'), ('f', '/pkg/a1/b')
         ]
 
         # paths
-        options.exclude = "/pkg/a1/"
+        options.exclude = ["/pkg/a1/"]
         fscache = FakeFSCache(files)
         assert find_sources(["/"], options, fscache) == [
             ("a2", "/pkg"),
@@ -339,15 +339,17 @@ def test_find_sources_exclude(self) -> None:
         with pytest.raises(InvalidSourceList):
             find_sources(["/pkg/a1"], options, fscache)
 
-        options.exclude = "/(a1|a3)/"
-        fscache = FakeFSCache(files)
-        assert find_sources(["/"], options, fscache) == [
-            ("a2", "/pkg"),
-            ("a2.b.c.d.e", "/pkg"),
-            ("a2.b.f", "/pkg"),
-        ]
+        # OR two patterns together
+        for orred in [["/(a1|a3)/"], ["a1", "a3"], ["a3", "a1"]]:
+            options.exclude = orred
+            fscache = FakeFSCache(files)
+            assert find_sources(["/"], options, fscache) == [
+                ("a2", "/pkg"),
+                ("a2.b.c.d.e", "/pkg"),
+                ("a2.b.f", "/pkg"),
+            ]
 
-        options.exclude = "b/c/"
+        options.exclude = ["b/c/"]
         fscache = FakeFSCache(files)
         assert find_sources(["/"], options, fscache) == [
             ("a2", "/pkg"),
@@ -356,19 +358,22 @@ def test_find_sources_exclude(self) -> None:
         ]
 
         # nothing should be ignored as a result of this
-        options.exclude = "|".join((
+        big_exclude1 = [
             "/pkg/a/", "/2", "/1", "/pk/", "/kg", "/g.py", "/bc", "/xxx/pkg/a2/b/f.py"
             "xxx/pkg/a2/b/f.py",
-        ))
-        fscache = FakeFSCache(files)
-        assert len(find_sources(["/"], options, fscache)) == len(files)
-
-        files = {
-            "pkg/a1/b/c/d/e.py",
-            "pkg/a1/b/f.py",
-            "pkg/a2/__init__.py",
-            "pkg/a2/b/c/d/e.py",
-            "pkg/a2/b/f.py",
-        }
-        fscache = FakeFSCache(files)
-        assert len(find_sources(["."], options, fscache)) == len(files)
+        ]
+        big_exclude2 = ["|".join(big_exclude1)]
+        for big_exclude in [big_exclude1, big_exclude2]:
+            options.exclude = big_exclude
+            fscache = FakeFSCache(files)
+            assert len(find_sources(["/"], options, fscache)) == len(files)
+
+            files = {
+                "pkg/a1/b/c/d/e.py",
+                "pkg/a1/b/f.py",
+                "pkg/a2/__init__.py",
+                "pkg/a2/b/c/d/e.py",
+                "pkg/a2/b/f.py",
+            }
+            fscache = FakeFSCache(files)
+            assert len(find_sources(["."], options, fscache)) == len(files)