Add OSError handling in find_imports_in_file

isort/api.py

@@ -588,15 +588,18 @@ def find_imports_in_file(
     - **top_only**: If True, only return imports that occur before the first function or class.
     - ****config_kwargs**: Any config modifications.
     """
-    with io.File.read(filename) as source_file:
-        yield from find_imports_in_stream(
-            input_stream=source_file.stream,
-            config=config,
-            file_path=file_path or source_file.path,
-            unique=unique,
-            top_only=top_only,
-            **config_kwargs,
-        )
+    try:
+        with io.File.read(filename) as source_file:
+            yield from find_imports_in_stream(
+                input_stream=source_file.stream,
+                config=config,
+                file_path=file_path or source_file.path,
+                unique=unique,
+                top_only=top_only,
+                **config_kwargs,
+            )
+    except OSError as error:
+        warn(f"Unable to parse file {filename} due to {error}")
 
 
 def find_imports_in_paths(

tests/unit/test_api.py

@@ -94,6 +94,13 @@ def test_find_imports_in_file(imperfect):
     assert "b" in [found_import.module for found_import in found_imports]
 
 
+def test_find_imports_in_file_error(tmpdir):
+    broken_link = tmpdir.join("broken_link.py")
+    broken_link.mksymlinkto("not-exist")
+    with pytest.warns(UserWarning):
+        assert not list(api.find_imports_in_file(broken_link))
+
+
 def test_find_imports_in_code():
     code = """
 from x.y import z as a