Fix: destination parameter bug #98

romanr · 2026-01-10T20:45:49Z

This prevents not being able to run macOS builds at all because "iOS" was injected as destination regardless of destination parameter passed.
Fixes: prevent stale iOS simulator destinations from being applied, avoid hidden overrides when the caller provided a destination.

fix argument handling so caller-supplied parameters are preserved and tracked, while cached values only fill genuine gaps; destination/sdk/config now resolve through an explicit/compatible path rather than being overwritten by prior runs (build.ts:73-118).
Updated to correctly report when smart defaults were applied, based on whether the caller actually provided each parameter (build.ts:193-218).
destination resolution: explicit destinations always win; cached destinations are only reused when platform-compatible; macOS and device SDKs avoid simulator carry-over; simulator suggestions are platform-filtered and derived from runtime tokens without hardcoded platform switches (build.ts:321-449).

…uddy#93

…to latest 1.25.1 which depends on zod v4 which has breaking changes.

…ssue and produces streaming output. Which caused xc-mcp to not return anything at all. Enhanced xcodebuild output with immediate error/warning visibility and streaming command execution.

…ning on macOS platform.

Copilot

Pull request overview

This pull request fixes a critical bug where iOS simulator destinations were incorrectly applied to macOS builds, preventing macOS builds from running. The fix introduces explicit parameter tracking, platform-compatible destination resolution, and enhanced build output visibility.

Changes:

Introduced explicit parameter tracking to distinguish caller-provided vs. cached values, preventing stale destinations from overriding explicit parameters
Implemented platform-aware destination resolution that filters simulator suggestions by platform and avoids simulator carry-over for macOS/device builds
Enhanced build output with top-level errors/warnings arrays (first 10 each) and added fatal pattern detection with early termination

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
`src/tools/xcodebuild/build.ts`	Core fix: parameter tracking, destination resolution logic, platform-compatible caching, streaming command execution with fatal pattern detection
`src/utils/command.ts`	Added executeCommandStreaming function with timeout and fatal pattern detection capabilities
`src/utils/response-cache.ts`	Enhanced extractBuildSummary to include first 10 errors and warnings arrays for immediate visibility
`tests/__tests__/tools/xcodebuild-build.test.ts`	New comprehensive test suite validating destination resolution, parameter precedence, and platform matching
`tests/__tests__/utils/response-cache.test.ts`	Added tests for errors/warnings arrays including 10-item limit validation
`README.md`	Updated documentation to reflect immediate error/warning visibility without secondary calls
`package.json`, `package-lock.json`, `src/index.ts`	Version updates and dependency pinning

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Copilot · 2026-01-10T20:50:25Z

README.md

+  summary: { errorCount: 0, warningCount: 1, duration: 5000 }
+}
+// Only use xcodebuild-get-details for full logs or >10 errors/warnings
+\`\`\`


The code block uses escaped backticks (\\\\`) instead of regular markdown code fence backticks. This will render incorrectly in markdown - the backslashes should be removed so it displays as a proper code block.

Copilot · 2026-01-10T20:50:25Z

src/tools/xcodebuild/build.ts

+  const provided = {
+    configuration: Object.prototype.hasOwnProperty.call(rawArgs, 'configuration'),
+    destination: Object.prototype.hasOwnProperty.call(rawArgs, 'destination'),
+    sdk: Object.prototype.hasOwnProperty.call(rawArgs, 'sdk'),
+    derivedDataPath: Object.prototype.hasOwnProperty.call(rawArgs, 'derivedDataPath'),
+  };


Using Object.prototype.hasOwnProperty.call() is the correct safe approach to check property existence. However, the check only verifies if the property exists on the object, not if it's explicitly defined by the caller. For example, if destructuring provides a default value (e.g., 'configuration = "Debug"' on line 78), the property would still exist in rawArgs. Consider documenting this behavior or ensuring that defaults are not applied during destructuring if you want to distinguish between explicitly-provided and defaulted parameters.

Copilot · 2026-01-10T20:50:25Z

README.md

 {
  buildId: "build-abc123",
  success: true,
+  warnings: ["...warning: unused variable 'foo'..."],  // first 10 warnings


The code comment says "first 10 warnings" but the actual implementation in response-cache.ts slices both errors and warnings to the first 10. The comment should be updated to mention both errors and warnings for consistency.

Suggested change

warnings: ["...warning: unused variable 'foo'..."], // first 10 warnings

warnings: ["...warning: unused variable 'foo'..."], // first 10 warnings (errors similarly truncated)

Copilot · 2026-01-10T20:50:26Z

src/tools/xcodebuild/build.ts

+    const augmentedErrors = [...summary.errors];
+    if (result.fatalMatch) {
+      augmentedErrors.unshift(`Detected fatal xcodebuild output: ${result.fatalMatch}`);
+    }
+    if (result.timedOut) {
+      augmentedErrors.unshift(`Build aborted after ${timeoutMs}ms (timeout)`);
+    }


The error augmentation logic uses unshift to add fatal errors at the beginning, but since errors array is already sliced to 10 items in extractBuildSummary, this could result in more than 10 errors being returned. Consider slicing augmentedErrors after all additions to maintain the 10-item limit mentioned in the documentation.

Copilot · 2026-01-10T20:50:26Z

src/utils/command.ts

+export async function executeCommandStreaming(
+  command: string,
+  options: StreamingOptions = {}
+): Promise<StreamingCommandResult> {
+  const {
+    timeout = 60000,
+    maxBuffer = 10 * 1024 * 1024,
+    fatalPatterns = [],
+    onFatalMatch,
+  } = options;
+
+  return new Promise<StreamingCommandResult>((resolve, reject) => {
+    const child = spawn(command, { shell: true, timeout });
+
+    let stdout = '';
+    let stderr = '';
+    let timedOut = false;
+    let fatalMatch: string | undefined;
+
+    const checkPatterns = (chunk: string) => {
+      if (fatalMatch) return;
+      for (const pattern of fatalPatterns) {
+        const match = chunk.match(pattern);
+        if (match) {
+          fatalMatch = match[0];
+          onFatalMatch?.(match[0]);
+          child.kill();
+          break;
+        }
+      }
+    };
+
+    const timeoutId = setTimeout(() => {
+      timedOut = true;
+      child.kill();
+    }, timeout);
+
+    child.stdout?.on('data', data => {
+      const text = data.toString();
+      stdout += text;
+      checkPatterns(text);
+      if (stdout.length > maxBuffer) {
+        child.kill();
+        clearTimeout(timeoutId);
+        reject(
+          new McpError(
+            ErrorCode.InternalError,
+            `Command output exceeded max buffer size of ${maxBuffer} bytes`
+          )
+        );
+      }
+    });
+
+    child.stderr?.on('data', data => {
+      const text = data.toString();
+      stderr += text;
+      checkPatterns(text);
+    });
+
+    child.on('close', code => {
+      clearTimeout(timeoutId);
+      resolve({
+        stdout: stdout.trim(),
+        stderr: stderr.trim(),
+        code: code ?? 0,
+        timedOut,
+        fatalMatch,
+      });
+    });
+
+    child.on('error', error => {
+      clearTimeout(timeoutId);
+      reject(new McpError(ErrorCode.InternalError, `Failed to execute command: ${error.message}`));
+    });
+  });
+}


The new executeCommandStreaming function introduced in this PR lacks unit test coverage. Since tests/tests/utils/command.test.ts exists and tests other command utilities, consider adding comprehensive tests for executeCommandStreaming including timeout scenarios, fatal pattern detection, and buffer overflow handling.

Copilot · 2026-01-10T20:50:26Z

README.md

+
 ## Example: Optimal Login Flow

 \`\`\`typescript


The code block uses escaped backticks (\\\\`) instead of regular markdown code fence backticks. This will render incorrectly in markdown - the backslashes should be removed so it displays as a proper code block.

Copilot · 2026-01-10T20:50:27Z

src/tools/xcodebuild/build.ts

    }

+    // Destructure errors/warnings from summary for top-level placement
+    const { errors: _ignoredErrors, warnings, ...summaryRest } = adjustedSummary;


The destructuring operation extracts 'errors' from adjustedSummary and renames it to '_ignoredErrors', but then uses the separate 'augmentedErrors' array for the top-level errors field. This is correct but the naming could be clearer. Consider renaming '_ignoredErrors' to '_summaryErrors' to better communicate that these are the summary's error list (which is superseded by augmentedErrors).

Suggested change

const { errors: _ignoredErrors, warnings, ...summaryRest } = adjustedSummary;

const { errors: _summaryErrors, warnings, ...summaryRest } = adjustedSummary;

Copilot · 2026-01-10T20:50:27Z

src/index.ts

      {
        name: 'xc-mcp',
-        version: '3.2.0',
+        version: '3.2.1',


Version mismatch detected: package.json declares version 3.2.2, but src/index.ts declares version 3.2.1. These versions should be synchronized to avoid confusion.

Suggested change

version: '3.2.1',

version: '3.2.2',

Copilot · 2026-01-10T20:50:27Z

tests/__tests__/tools/xcodebuild-build.test.ts

+describe('xcodebuild-build parameter resolution', () => {
+  const projectPath = 'SpaceTime.xcodeproj';
+  const scheme = 'SpaceTime';
+
+  const successResult = {
+    stdout: '',
+    stderr: '',
+    code: 0,
+    timedOut: false,
+  };
+
+  beforeEach(() => {
+    jest.resetModules();
+    jest.clearAllMocks();
+
+    mockBuildXcodebuildCommand.mockImplementation((action: string, path: string, opts: any) =>
+      JSON.stringify({ action, path, opts })
+    );
+    mockExecuteCommandStreaming.mockResolvedValue(successResult);
+    mockExtractBuildSummary.mockReturnValue({
+      success: true,
+      errors: [],
+      warnings: [],
+      errorCount: 0,
+      warningCount: 0,
+      buildSizeBytes: 0,
+    });
+    mockResponseCacheStore.mockReturnValue('build-id');
+    mockCreateConfigManager.mockReturnValue({
+      recordSuccessfulBuild: jest.fn(),
+    });
+  });
+
+  async function loadTool() {
+    const mod = await import('../../../src/tools/xcodebuild/build.js');
+    return mod.xcodebuildBuildTool;
+  }
+
+  function responseFrom(result: any) {
+    return JSON.parse(result.content[0].text);
+  }
+
+  it('uses explicit destination and does not override it', async () => {
+    mockGetPreferredBuildConfig.mockResolvedValue({
+      scheme,
+      configuration: 'Release',
+      destination: 'platform=iOS Simulator,id=CACHED',
+    });
+
+    const xcodebuildBuildTool = await loadTool();
+
+    const result = await xcodebuildBuildTool({
+      projectPath,
+      scheme,
+      destination: 'generic/platform=macOS,name=Any Mac',
+      sdk: 'macosx',
+    });
+
+    const lastCall = mockBuildXcodebuildCommand.mock.calls.at(-1)![2] as any;
+    expect(lastCall.destination).toBe('generic/platform=macOS,name=Any Mac');
+    expect(mockGetPreferredSimulator).not.toHaveBeenCalled();
+
+    const response = responseFrom(result);
+    expect(response.intelligence.usedSmartDestination).toBe(false);
+  });
+
+  it('skips cached simulator destination when building for macOS', async () => {
+    mockGetPreferredBuildConfig.mockResolvedValue({
+      scheme,
+      configuration: 'Debug',
+      destination: 'platform=iOS Simulator,id=CACHED',
+    });
+
+    const xcodebuildBuildTool = await loadTool();
+
+    const result = await xcodebuildBuildTool({
+      projectPath,
+      scheme,
+      sdk: 'macosx',
+    });
+
+    const lastCall = mockBuildXcodebuildCommand.mock.calls.at(-1)![2] as any;
+    expect(lastCall.destination).toBeUndefined();
+
+    const response = responseFrom(result);
+    expect(response.intelligence.usedSmartDestination).toBe(false);
+  });
+
+  it('reuses cached destination when platform matches sdk', async () => {
+    mockGetPreferredBuildConfig.mockResolvedValue({
+      scheme,
+      configuration: 'Debug',
+      destination: 'platform=tvOS Simulator,id=TV-1',
+    });
+
+    const xcodebuildBuildTool = await loadTool();
+
+    const result = await xcodebuildBuildTool({
+      projectPath,
+      scheme,
+      sdk: 'tvossimulator',
+    });
+
+    const lastCall = mockBuildXcodebuildCommand.mock.calls.at(-1)![2] as any;
+    expect(lastCall.destination).toBe('platform=tvOS Simulator,id=TV-1');
+
+    const response = responseFrom(result);
+    expect(response.intelligence.usedSmartDestination).toBe(true);
+  });
+
+  it('selects a platform-matched simulator when no cached destination', async () => {
+    mockGetPreferredBuildConfig.mockResolvedValue({
+      scheme,
+      configuration: 'Debug',
+    });
+
+    mockGetPreferredSimulator.mockResolvedValue(null);
+    mockGetSimulatorList.mockResolvedValue({
+      devices: {
+        'com.apple.CoreSimulator.SimRuntime.tvOS-18-0': [
+          {
+            udid: 'TV-UDID',
+            name: 'Apple TV',
+            deviceTypeIdentifier: 'com.apple.CoreSimulator.SimDeviceType.Apple-TV-4K',
+            state: 'Shutdown',
+            isAvailable: true,
+            availability: 'available',
+            bootHistory: [],
+          },
+        ],
+        'com.apple.CoreSimulator.SimRuntime.iOS-18-0': [
+          {
+            udid: 'PHONE',
+            name: 'iPhone',
+            deviceTypeIdentifier: 'com.apple.CoreSimulator.SimDeviceType.iPhone-16',
+            state: 'Shutdown',
+            isAvailable: true,
+            availability: 'available',
+            bootHistory: [],
+          },
+        ],
+      },
+      runtimes: [],
+      devicetypes: [],
+      lastUpdated: new Date(),
+      preferredByProject: new Map(),
+    });
+
+    const xcodebuildBuildTool = await loadTool();
+
+    const result = await xcodebuildBuildTool({
+      projectPath,
+      scheme,
+      sdk: 'tvossimulator',
+    });
+
+    const lastCall = mockBuildXcodebuildCommand.mock.calls.at(-1)![2] as any;
+    expect(lastCall.destination).toBe('platform=tvOS Simulator,id=TV-UDID');
+
+    const response = responseFrom(result);
+    expect(response.intelligence.usedSmartDestination).toBe(true);
+  });
+
+  it('prioritizes caller-provided configuration over cached', async () => {
+    mockGetPreferredBuildConfig.mockResolvedValue({
+      scheme,
+      configuration: 'Debug',
+    });
+
+    const xcodebuildBuildTool = await loadTool();
+
+    await xcodebuildBuildTool({
+      projectPath,
+      scheme,
+      configuration: 'Release',
+    });
+
+    const lastCall = mockBuildXcodebuildCommand.mock.calls.at(-1)![2] as any;
+    expect(lastCall.configuration).toBe('Release');
+  });
+
+  it('uses cached configuration when caller does not provide one and marks smart usage', async () => {
+    mockGetPreferredBuildConfig.mockResolvedValue({
+      scheme,
+      configuration: 'Release',
+    });
+
+    const xcodebuildBuildTool = await loadTool();
+
+    const result = await xcodebuildBuildTool({
+      projectPath,
+      scheme,
+    });
+
+    const lastCall = mockBuildXcodebuildCommand.mock.calls.at(-1)![2] as any;
+    expect(lastCall.configuration).toBe('Release');
+
+    const response = responseFrom(result);
+    expect(response.intelligence.usedSmartConfiguration).toBe(true);
+  });
+});


The new fatal pattern detection and timeout handling features introduced in executeCommandStreaming and build.ts lack test coverage. Consider adding test cases for scenarios where timeout occurs (timedOut: true) or when a fatal pattern is matched (fatalMatch is set).

Copilot · 2026-01-10T20:50:27Z

src/tools/xcodebuild/build.ts

+  const baseName = lastSegment.split('-')[0];
+  if (!baseName) return undefined;


The platformLabelFromRuntime function assumes the runtime format has a segment with a dash separator (e.g., 'tvOS-18-0'), but if the runtime string doesn't contain a dash, baseName will be the entire lastSegment. Consider adding defensive handling for runtimes that don't follow the expected format to avoid malformed platform labels like 'com Simulator' or 'SimRuntime Simulator'.

Suggested change

const baseName = lastSegment.split('-')[0];

if (!baseName) return undefined;

if (!lastSegment) return undefined;

const hasDash = lastSegment.includes('-');

const baseName = hasDash ? lastSegment.split('-')[0] : lastSegment;

if (!baseName) return undefined;

// If there is no dash in the last segment, make sure the base name looks like a platform

// token before constructing a label. This avoids labels like "com Simulator" or

// "SimRuntime Simulator" for unexpected runtime formats.

if (!hasDash) {

const lower = baseName.toLowerCase();

const looksLikePlatform =

lower.includes('mac') ||

lower.includes('iphone') ||

lower.includes('ios') ||

lower.includes('tvos') ||

lower.includes('appletv') ||

lower.includes('watch') ||

lower.includes('vision');

if (!looksLikePlatform) {

return undefined;

}

}

romanr added 6 commits December 30, 2025 21:40

feat: Enhance build summary to include errors and warnings fix conorl…

353974d

…uddy#93

fix: conorluddy#91 : "@modelcontextprotocol/sdk": "^1.17.1" resolves …

58cfa96

…to latest 1.25.1 which depends on zod v4 which has breaking changes.

Errors and warnings at top level

9d29ea3

Fix: failed to detect when xcodebuild encounters "simulator locked" i…

f777d06

…ssue and produces streaming output. Which caused xc-mcp to not return anything at all. Enhanced xcodebuild output with immediate error/warning visibility and streaming command execution.

chore: Bump version to 3.2.1

a7ce32d

fix: xcodebuildBuildTool parameter resolution that prevented from run…

2449808

…ning on macOS platform.

Copilot AI review requested due to automatic review settings January 10, 2026 20:45

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Fix: destination parameter bug #98

Fix: destination parameter bug #98

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	warnings: ["...warning: unused variable 'foo'..."], // first 10 warnings
	warnings: ["...warning: unused variable 'foo'..."], // first 10 warnings (errors similarly truncated)

	const { errors: _ignoredErrors, warnings, ...summaryRest } = adjustedSummary;
	const { errors: _summaryErrors, warnings, ...summaryRest } = adjustedSummary;

		const baseName = lastSegment.split('-')[0];
		if (!baseName) return undefined;

-  const baseName = lastSegment.split('-')[0];
-  if (!baseName) return undefined;
+  if (!lastSegment) return undefined;
+  const hasDash = lastSegment.includes('-');
+  const baseName = hasDash ? lastSegment.split('-')[0] : lastSegment;
+  if (!baseName) return undefined;
+  // If there is no dash in the last segment, make sure the base name looks like a platform
+  // token before constructing a label. This avoids labels like "com Simulator" or
+  // "SimRuntime Simulator" for unexpected runtime formats.
+  if (!hasDash) {
+    const lower = baseName.toLowerCase();
+    const looksLikePlatform =
+      lower.includes('mac') ||
+      lower.includes('iphone') ||
+      lower.includes('ios') ||
+      lower.includes('tvos') ||
+      lower.includes('appletv') ||
+      lower.includes('watch') ||
+      lower.includes('vision');
+    if (!looksLikePlatform) {
+      return undefined;
+    }
+  }

Fix: destination parameter bug #98

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Fix: destination parameter bug #98

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