fix(patch): cherry-pick 1cae5ab to release/v0.28.0-preview.3-pr-18376 to patch version v0.28.0-preview.3 and create version 0.28.0-preview.4

[gemini-cli-robot]

This PR automatically cherry-picks commit 1cae5ab to patch version v0.28.0-preview.3 in the preview release to create version 0.28.0-preview.4.

[gemini-code-assist]

Summary of Changes

Hello @gemini-cli-robot, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request implements a targeted solution to rectify an incompatibility issue with Xcode 26.3's mcpbridge tool, which was found to produce malformed JSON-RPC responses. By introducing an intermediary transport layer, the system can now seamlessly process these responses, ensuring robust communication and functionality when integrating with Xcode's developer tools.

Highlights

• Xcode MCP Bridge Fix: Introduced a new XcodeMcpBridgeFixTransport to address non-compliant JSON-RPC responses from Xcode 26.3's mcpbridge tool. This transport intercepts messages and correctly populates the structuredContent field when it's missing but the content field contains stringified JSON.
• Conditional Transport Application: The mcp-client.ts file has been updated to conditionally apply the XcodeMcpBridgeFixTransport wrapper only when the mcpbridge command is executed via xcrun, ensuring the fix is targeted where needed.
• Enhanced Debugging for Wrapped Transports: Modified the debug logging mechanism to correctly access the stderr stream of the underlying StdioClientTransport even when it's wrapped by XcodeMcpBridgeFixTransport, preserving debugging capabilities.
• Comprehensive Unit Tests: Added a dedicated test file (xcode-mcp-fix-transport.test.ts) with unit tests for the XcodeMcpBridgeFixTransport, covering scenarios where non-compliant responses are fixed, compliant responses are passed through, and non-JSON content is ignored.

Changelog

• packages/core/src/tools/mcp-client.ts
  • Imported XcodeMcpBridgeFixTransport for use in the client.
  • Modified the createTransport function to allow reassignment of the transport variable.
  • Implemented logic to wrap the StdioClientTransport with XcodeMcpBridgeFixTransport if the command is xcrun mcpbridge.
  • Updated stderr debug logging to correctly handle the wrapped transport by unwrapping it to access the underlying stream.
• packages/core/src/tools/xcode-mcp-fix-transport.test.ts
  • Added a new file containing unit tests for the XcodeMcpBridgeFixTransport.
  • Tests verify that non-compliant mcpbridge responses are correctly fixed by populating structuredContent.
  • Tests confirm that compliant responses are passed through without modification.
  • Tests ensure that responses with non-JSON text in content are ignored.
• packages/core/src/tools/xcode-mcp-fix-transport.ts
  • Added a new file defining the XcodeMcpBridgeFixTransport class.
  • Implemented a wrapper transport that intercepts JSONRPCMessages.
  • Added fixStructuredContent method to parse stringified JSON from result.content and populate result.structuredContent when it's missing.

Activity

• This pull request was automatically generated by gemini-cli-robot to cherry-pick a fix into a preview release branch.

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[github-actions]

Size Change: +2.39 kB (+0.01%)

Total Size: 23.7 MB

Filename	Size	Change
./bundle/gemini.js	23.7 MB	+2.39 kB (+0.01%)

ℹ️ View Unchanged

Filename	Size
./bundle/sandbox-macos-permissive-closed.sb	1.03 kB
./bundle/sandbox-macos-permissive-open.sb	890 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB
./bundle/sandbox-macos-restrictive-closed.sb	3.29 kB
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB

_{compressed-size-action}

[gemini-code-assist]

Code Review

This pull request cherry-picks a fix for non-compliant responses from Xcode's mcpbridge. It introduces a new XcodeMcpBridgeFixTransport wrapper to intercept and correct these responses. The implementation is sound and includes relevant tests. My review includes suggestions to improve encapsulation by avoiding access to private properties through type assertions, which will make the code more robust and maintainable.

[gemini-code-assist]

Accessing the private transport property using as any is a workaround that breaks encapsulation. Once the transport property in XcodeMcpBridgeFixTransport is made public (as suggested in another comment), you can access it directly without the type cast and eslint-disable comment, making the code cleaner and more robust.

      const underlyingTransport =
        transport instanceof XcodeMcpBridgeFixTransport
          ? transport.transport
          : transport;

[gemini-code-assist]

The transport property is marked as private, but it's being accessed from mcp-client.ts using a type assertion (as any). This breaks encapsulation and makes the code brittle. To provide proper, type-safe access, please change the visibility of transport to public.

Suggested change

	constructor(private readonly transport: Transport) {
	constructor(public readonly transport: Transport) {