Fix the regex in `get_imports` to support multiline try blocks and excepts with specific exception types (#23725)

* fix and test get_imports for multiline try blocks, and excepts with specific errors

* fixup

* add some more tests

* add license

src/transformers/dynamic_module_utils.py

@@ -123,7 +123,7 @@ def get_imports(filename):
         content = f.read()
 
     # filter out try/except block so in custom code we can have try/except imports
-    content = re.sub(r"\s*try\s*:\s*.*?\s*except\s*:", "", content, flags=re.MULTILINE)
+    content = re.sub(r"\s*try\s*:\s*.*?\s*except\s*.*?:", "", content, flags=re.MULTILINE | re.DOTALL)
 
     # Imports of the form `import xxx`
     imports = re.findall(r"^\s*import\s+(\S+)\s*$", content, flags=re.MULTILINE)

tests/utils/test_dynamic_module_utils.py

@@ -0,0 +1,129 @@
+# Copyright 2023 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+import pytest
+
+from transformers.dynamic_module_utils import get_imports
+
+
+TOP_LEVEL_IMPORT = """
+import os
+"""
+
+IMPORT_IN_FUNCTION = """
+def foo():
+    import os
+    return False
+"""
+
+DEEPLY_NESTED_IMPORT = """
+def foo():
+    def bar():
+        if True:
+            import os
+        return False
+    return bar()
+"""
+
+TOP_LEVEL_TRY_IMPORT = """
+import os
+
+try:
+    import bar
+except ImportError:
+    raise ValueError()
+"""
+
+TRY_IMPORT_IN_FUNCTION = """
+import os
+
+def foo():
+    try:
+        import bar
+    except ImportError:
+        raise ValueError()
+"""
+
+MULTIPLE_EXCEPTS_IMPORT = """
+import os
+
+try:
+    import bar
+except (ImportError, AttributeError):
+    raise ValueError()
+"""
+
+EXCEPT_AS_IMPORT = """
+import os
+
+try:
+    import bar
+except ImportError as e:
+    raise ValueError()
+"""
+
+GENERIC_EXCEPT_IMPORT = """
+import os
+
+try:
+    import bar
+except:
+    raise ValueError()
+"""
+
+MULTILINE_TRY_IMPORT = """
+import os
+
+try:
+    import bar
+    import baz
+except ImportError:
+    raise ValueError()
+"""
+
+MULTILINE_BOTH_IMPORT = """
+import os
+
+try:
+    import bar
+    import baz
+except ImportError:
+    x = 1
+    raise ValueError()
+"""
+
+CASES = [
+    TOP_LEVEL_IMPORT,
+    IMPORT_IN_FUNCTION,
+    DEEPLY_NESTED_IMPORT,
+    TOP_LEVEL_TRY_IMPORT,
+    GENERIC_EXCEPT_IMPORT,
+    MULTILINE_TRY_IMPORT,
+    MULTILINE_BOTH_IMPORT,
+    MULTIPLE_EXCEPTS_IMPORT,
+    EXCEPT_AS_IMPORT,
+    TRY_IMPORT_IN_FUNCTION,
+]
+
+
+@pytest.mark.parametrize("case", CASES)
+def test_import_parsing(tmp_path, case):
+    tmp_file_path = os.path.join(tmp_path, "test_file.py")
+    with open(tmp_file_path, "w") as _tmp_file:
+        _tmp_file.write(case)
+
+    parsed_imports = get_imports(tmp_file_path)
+    assert parsed_imports == ["os"]