Lazy load model data classes

.github/workflows/ci.yml

@@ -73,3 +73,8 @@ jobs:
       - name: Run protocol tests
         run: |
           make generate-protocol-tests test-protocols
+
+      - name: Type-check protocol test stubs
+        if: ${{ matrix.python-version == '3.12' }}
+        run: |
+          make typecheck-protocols

Makefile

@@ -24,11 +24,20 @@ build-java: ## Builds and tests the Java code generation packages without modify
 
 test-protocols: ## Generates and runs protocol tests for all supported protocols.
 	cd codegen && ./gradlew :protocol-test:clean :protocol-test:build
+	uv pip install -e packages/smithy-test
 	@set -e; for projection_dir in codegen/protocol-test/build/smithyprojections/protocol-test/*/python-client-codegen; do \
 		uv pip install "$$projection_dir"; \
 		uv run pytest "$$projection_dir"; \
 	done
 
+# pyright's wrapper imports typing_extensions, which fails to import on 3.15
+# (removed typing.no_type_check_decorator); run the stub type-check on 3.12 only.
+typecheck-protocols: ## Type-checks the generated protocol-test stub fixtures with pyright.
+	@set -e; for projection_dir in codegen/protocol-test/build/smithyprojections/protocol-test/*/python-client-codegen; do \
+		uv pip install "$$projection_dir"; \
+		uv run pyright "$$projection_dir/tests/_typecheck.py"; \
+	done
+
 
 generate-protocol-tests: ## Generates protocol-test clients, copies them to ./codegen-output, and asserts no git diff.
 	cd codegen && ./gradlew :protocol-test:clean :protocol-test:build

codegen-output/aws-json-1-0/pyproject.toml

@@ -53,6 +53,9 @@ reportUnusedVariable = false
 reportUnnecessaryComparison = false
 reportUnusedClass = false
 enableExperimentalFeatures = true
+# models.py is the dynamic runtime; models.pyi carries the typed
+# surface for consumers, so don't type-check the implementation body.
+exclude = ["**/models.py"]
 
 [tool.ruff]
 target-version = "py312"