♻️ Update logic to import and check `python-multipart` for compatibility with newer version (#12627)

fastapi/dependencies/utils.py

@@ -89,16 +89,24 @@ multipart_incorrect_install_error = (
 
 
 def ensure_multipart_is_installed() -> None:
+    try:
+        from python_multipart import __version__
+
+        # Import an attribute that can be mocked/deleted in testing
+        assert __version__ > "0.0.12"
+    except (ImportError, AssertionError):
         try:
             # __version__ is available in both multiparts, and can be mocked
-        from multipart import __version__
+            from multipart import __version__  # type: ignore[no-redef,import-untyped]
 
             assert __version__
             try:
                 # parse_options_header is only available in the right multipart
-            from multipart.multipart import parse_options_header
+                from multipart.multipart import (  # type: ignore[import-untyped]
+                    parse_options_header,
+                )
 
-            assert parse_options_header  # type: ignore[truthy-function]
+                assert parse_options_header
             except ImportError:
                 logger.error(multipart_incorrect_install_error)
                 raise RuntimeError(multipart_incorrect_install_error) from None

tests/test_multipart_installation.py

@@ -1,3 +1,5 @@
+import warnings
+
 import pytest
 from fastapi import FastAPI, File, Form, UploadFile
 from fastapi.dependencies.utils import (
@@ -7,6 +9,9 @@ from fastapi.dependencies.utils import (
 
 
 def test_incorrect_multipart_installed_form(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
     with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
         app = FastAPI()
@@ -17,6 +22,9 @@ def test_incorrect_multipart_installed_form(monkeypatch):
 
 
 def test_incorrect_multipart_installed_file_upload(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
     with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
         app = FastAPI()
@@ -27,6 +35,9 @@ def test_incorrect_multipart_installed_file_upload(monkeypatch):
 
 
 def test_incorrect_multipart_installed_file_bytes(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
     with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
         app = FastAPI()
@@ -37,6 +48,9 @@ def test_incorrect_multipart_installed_file_bytes(monkeypatch):
 
 
 def test_incorrect_multipart_installed_multi_form(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
     with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
         app = FastAPI()
@@ -47,6 +61,9 @@ def test_incorrect_multipart_installed_multi_form(monkeypatch):
 
 
 def test_incorrect_multipart_installed_form_file(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
     with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
         app = FastAPI()
@@ -57,6 +74,9 @@ def test_incorrect_multipart_installed_form_file(monkeypatch):
 
 
 def test_no_multipart_installed(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.__version__", raising=False)
         with pytest.raises(RuntimeError, match=multipart_not_installed_error):
             app = FastAPI()
@@ -67,6 +87,9 @@ def test_no_multipart_installed(monkeypatch):
 
 
 def test_no_multipart_installed_file(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.__version__", raising=False)
         with pytest.raises(RuntimeError, match=multipart_not_installed_error):
             app = FastAPI()
@@ -77,6 +100,9 @@ def test_no_multipart_installed_file(monkeypatch):
 
 
 def test_no_multipart_installed_file_bytes(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.__version__", raising=False)
         with pytest.raises(RuntimeError, match=multipart_not_installed_error):
             app = FastAPI()
@@ -87,6 +113,9 @@ def test_no_multipart_installed_file_bytes(monkeypatch):
 
 
 def test_no_multipart_installed_multi_form(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.__version__", raising=False)
         with pytest.raises(RuntimeError, match=multipart_not_installed_error):
             app = FastAPI()
@@ -97,6 +126,9 @@ def test_no_multipart_installed_multi_form(monkeypatch):
 
 
 def test_no_multipart_installed_form_file(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
         monkeypatch.delattr("multipart.__version__", raising=False)
         with pytest.raises(RuntimeError, match=multipart_not_installed_error):
             app = FastAPI()
@@ -104,3 +136,14 @@ def test_no_multipart_installed_form_file(monkeypatch):
             @app.post("/")
             async def root(username: str = Form(), f: UploadFile = File()):
                 return username  # pragma: nocover
+
+
+def test_old_multipart_installed(monkeypatch):
+    monkeypatch.setattr("python_multipart.__version__", "0.0.12")
+    with warnings.catch_warnings(record=True):
+        warnings.simplefilter("always")
+        app = FastAPI()
+
+        @app.post("/")
+        async def root(username: str = Form()):
+            return username  # pragma: nocover