Bug: False positive error count due to regex matching "error:" in non-error contexts

[barrettj]

Bug: False positive error count due to regex matching "error:" in non-error contexts

Problem: The tool is counting occurrences of error: in the build output, but this pattern appears in:

1. Method parameter names - Objective-C methods like error:(out NSError**)error
2. Warning messages that show code snippets containing methods with "error:" parameters

Example false positives:
178 | error:(out NSError**)error
This is just a code snippet in a warning message, not an actual error.

Suggested fix: The error parsing regex should look for lines that match actual Xcode error patterns like:

• ^/.+:\d+:\d+: error: (file:line:column: error:)
• Or check for error: at the start of a diagnostic message, not within quoted code

Workaround for now: The actual build status can be verified by checking if the log ends with "Build succeeded" or "Build failed".

Note: this is a report claude recommend I pass along after it started saying everything was failing for me when things were apparently succeeding

[barrettj]

I had claude fix it in my in memory copy and it seems to work well:

Proposed Fix

  File: xcode_mcp_server/utils/xcresult.py

  Lines 384-387 - Replace:
  # Pattern for compiler errors/warnings: matches "error:" or "warning:" at word boundaries
  # This avoids false positives from phrases like "error-free" or "no errors"
  error_pattern = re.compile(r'\berror\s*:', re.IGNORECASE)
  warning_pattern = re.compile(r'\bwarning\s*:', re.IGNORECASE)

  With:
  # Pattern for compiler errors/warnings in Xcode diagnostic format:
  # - file:line:column: error: message (typical compiler output)
  # - ^error: at start of line (standalone errors like linker errors)
  # This avoids false positives from Objective-C method signatures like "error:(NSError**)error"
  error_pattern = re.compile(r'(:\d+:\d+: error:)|(^error\s*:)', re.IGNORECASE | re.MULTILINE)
  warning_pattern = re.compile(r'(:\d+:\d+: warning:)|(^warning\s*:)', re.IGNORECASE | re.MULTILINE)

  Also update docstring (lines 322-326) to reflect the new behavior.

[drewster99]

Hi! Thank you for reporting this -- and also solving it. 😀 EXCELLENT CATCH!
I'll get it updated shortly.

[drewster99]

Actually let's try this claude mojo. @claude investigate this issue and see if the proposed fix is correct. If so, create a PR.

[claude]

Claude finished @drewster99's task in 2m 13s —— View job • claude/issue-2-20260109-1949 • Create PR ➔

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Investigation Complete

• Gather context and read relevant files
• Analyze the current implementation
• Verify the proposed fix
• Implement the fix
• Check for related tests
• Commit and push changes
• Provide PR creation link

Analysis

The issue was confirmed. The previous regex pattern \berror\s*: matched "error:" with word boundaries, causing false positives from:

• Objective-C method parameters: error:(NSError**)error
• Code snippets in warning messages containing method signatures with "error:" parameters

The proposed fix was correct and has been implemented.

Changes Made

Updated xcode_mcp_server/utils/xcresult.py:

• Lines 322-332: Updated docstring to explain the new Xcode diagnostic format matching approach
• Lines 387-392: Updated regex patterns to:
  • Match file:line:column: error: (typical compiler diagnostic format)
  • Match ^error: at start of line (standalone errors like linker errors)
  • Same approach for warnings

This prevents false positives from method signatures while correctly catching all actual Xcode build errors and warnings.

Testing

Existing tests in tests/test_build.py cover the build error and warning functionality. The tests verify that errors and warnings are properly detected and reported, and will now benefit from the more precise pattern matching.

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| Branch

[drewster99]

@claude create the PR

[barrettj]

I'd be lying if I said claude didn't come up with the fix :P

Will this be making its way to uv/uvx soon?

[drewster99]

Pushed to PyPi today so it should be there now, or shortly.

[barrettj]

Awesome - every time I have to do a clean build it picks up false errors from the Dropbox sdk and despite telling Claude.md about it, it never remembers