Allow valid targets alongside empty directories

mypy/find_sources.py

@@ -38,6 +38,7 @@ def create_source_list(
     finder = SourceFinder(fscache, options)
 
     sources = []
+    empty_dirs = []
     for path in paths:
         path = os.path.normpath(path)
         if path.endswith(PY_EXTENSIONS):
@@ -47,11 +48,14 @@ def create_source_list(
         elif fscache.isdir(path):
             sub_sources = finder.find_sources_in_dir(path)
             if not sub_sources and not allow_empty_dir:
-                raise InvalidSourceList(f"There are no .py[i] files in directory '{path}'")
+                empty_dirs.append(path)
             sources.extend(sub_sources)
         else:
             mod = os.path.basename(path) if options.scripts_are_modules else None
             sources.append(BuildSource(path, mod, None))
+    if not sources and empty_dirs:
+        empty_dirs_str = ", ".join(map(repr, empty_dirs))
+        raise InvalidSourceList(f"There are no .py[i] files in directories: {empty_dirs_str}")
     return sources
 
 

mypy/test/test_find_sources.py

@@ -261,6 +261,16 @@ def test_find_sources_in_dir_namespace_multi_dir(self) -> None:
         finder = SourceFinder(FakeFSCache({"/a/pkg/a.py", "/b/pkg/b.py"}), options)
         assert find_sources_in_dir(finder, "/") == [("pkg.a", "/a"), ("pkg.b", "/b")]
 
+    def test_find_sources_with_empty_directory(self) -> None:
+        options = Options()
+        fscache = FakeFSCache({"/empty/README", "/other'empty/README", "/src/a.py"})
+
+        assert find_sources(["/empty", "/src"], options, fscache) == [("a", "/src")]
+        with pytest.raises(InvalidSourceList, match="directories") as exc_info:
+            find_sources(["/empty", "/other'empty"], options, fscache)
+        assert repr(os.path.abspath("/empty")) in str(exc_info.value)
+        assert repr(os.path.abspath("/other'empty")) in str(exc_info.value)
+
     def test_find_sources_exclude(self) -> None:
         options = Options()
         options.namespace_packages = True