Java - Type cast null parameters in samples and tests

[Alan Zimmer (alzimmermsft)]

Adds type casting to null parameters in generated Java samples and tests to prevent ambiguous call site errors after generation.

[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-client-java

Show changes

@typespec/http-client-java - fix ✏️

Cast null arguments to their declared Java types in generated samples and tests so overloaded API calls are unambiguous.

[Copilot]

🟡 Changes recommended

One or more issues must be addressed before approval.

Get a fresh assessment by requesting another Copilot review.

Pull request overview

Updates Java emitter example generation so typed null arguments avoid ambiguous overloaded calls.

Changes:

• Added shared null-parameter casting logic.
• Applied it to protocol and client-method examples.
• Updated generated samples/tests and added coverage plus a changelog entry.

File summaries

File	Description
packages/http-client-java/generator/http-client-generator-test/src/test/java/tsptest/versioning/generated/VersioningOpListTests.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/test/java/tsptest/specialchars/generated/BuiltinOpReadTests.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/test/java/tsptest/model/generated/ModelOpPutNestedTests.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/test/java/tsptest/flatten/generated/FlattenOpSendTests.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/test/java/tsptest/builtin/generated/BuiltinOpReadTests.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/samples/java/tsptest/versioning/generated/VersioningOpList.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/samples/java/tsptest/specialchars/generated/BuiltinOpRead.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/samples/java/tsptest/model/generated/ModelOpPutNested.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/samples/java/tsptest/flatten/generated/FlattenOpSend.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-test/src/samples/java/tsptest/builtin/generated/BuiltinOpRead.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-core/src/test/java/com/microsoft/typespec/http/client/generator/core/template/example/ExampleWriterUtilTests.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-core/src/main/java/com/microsoft/typespec/http/client/generator/core/template/example/ProtocolExampleWriter.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-core/src/main/java/com/microsoft/typespec/http/client/generator/core/template/example/ExampleWriterUtil.java	Updated as part of this pull request.
packages/http-client-java/generator/http-client-generator-core/src/main/java/com/microsoft/typespec/http/client/generator/core/template/example/ClientMethodExampleWriter.java	Updated as part of this pull request.
.chronus/changes/http-client-java-cast-null-sample-arguments-2026-09-15.md	Updated as part of this pull request.

Review details

Suppressed comments (2)

packages/http-client-java/generator/http-client-generator-core/src/main/java/com/microsoft/typespec/http/client/generator/core/template/example/ClientMethodExampleWriter.java:67

• The added tests do not exercise this ClientMethodExampleWriter path; they only call ExampleWriterUtil.getParameterExpression directly. Add an entrypoint test for a client-method example with a typed null parameter so the parameter mapping, cast, and required import are verified together.

        String parameterInvocations = methodParameters.stream()
            .map(methodParameter -> ExampleWriterUtil.getParameterExpression(
                methodParameter.getClientMethodParameter().getClientType(),
                nodeVisitor.accept(parseNodeFromParameter(method, proxyMethodExample, methodParameter))))
            .collect(Collectors.joining(", "));

packages/http-client-java/generator/http-client-generator-core/src/main/java/com/microsoft/typespec/http/client/generator/core/template/example/ProtocolExampleWriter.java:82

• This new call site is not covered by the added tests: ExampleWriterUtilTests invokes the helper directly, so it would still pass if ProtocolExampleWriter stopped applying the cast or collecting the type import. Add a template/writer test that exercises a nullable non-java.lang parameter (for example OffsetDateTime) and asserts the rendered invocation and imports.

            params.add(ExampleWriterUtil.getParameterExpression(parameter.getClientType(),
                parameter.getClientType().defaultValueExpression()));

• Files reviewed: 5/15 changed files
• Comments generated: 1
• Review effort level: Lite

---

💡 Configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[azure-sdk-automation]

You can try these changes here

🛝 Playground	🌐 Website	🛝 VSCode Extension