Fix leading **/ glob to match zero-or-more directories

[robsyme]

Summary

• Transform leading **/ glob patterns to {,**/} in FileHelper.visitFiles() so they match files at the root level (zero directories) as well as in subdirectories

Test plan

• Added test case should match files at root and subdirectories with double-star glob
• Verified existing visitFiles tests still pass
• Run full test suite

Closes #6653

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[robsyme]

@claude review please

[claude]

Claude finished @robsyme's task —— View job

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PR Review: Fix leading **/ glob to match zero-or-more directories

Todo List:

• Read and analyze the modified FileHelper.groovy
• Review the test changes in FileHelperTest.groovy
• Analyze the glob pattern transformation logic
• Check test coverage and edge cases
• Provide comprehensive review feedback

Review Summary

This PR successfully addresses issue #6653 by transforming leading **/ glob patterns to {,**/} to match files at both the root level (zero directories) and in subdirectories. The implementation is clean, well-tested, and follows Java glob expansion conventions.

Code Analysis

Core Change (FileHelper.groovy:865-867)

final adjustedPattern = filePattern.startsWith('**/')
    ? "{,**/}" + filePattern.substring(3)
    : filePattern

✅ Strengths:

• Clear and correct logic: Transforms **/foo.bin → {,**/}foo.bin which expands to match both foo.bin and **/foo.bin
• Minimal scope: Only affects patterns that start with **/, preserving existing behavior for other patterns
• Efficient: Simple string manipulation with no regex overhead
• Well-documented: Clear comment explains the Java glob behavior being addressed

Test Coverage (FileHelperTest.groovy:627-667)

✅ Comprehensive test case:

• Tests files at root level: data.bin
• Tests files in subdirectory: subdir/data.bin
• Tests files in nested subdirectory: subdir/nested/data.bin
• Tests complex patterns: **/InterOp/*.bin matching at multiple levels
• Verifies expected behavior with proper assertions

Technical Assessment

Pattern Transformation Logic

The transformation **/pattern → {,**/}pattern is mathematically sound:

• {,**/} expands to two alternatives: empty string and **/
• This creates the union of matches: files at root + files in subdirectories
• Follows Java glob brace expansion semantics correctly

Edge Cases Considered

• ✅ Only transforms patterns starting with **/
• ✅ Preserves patterns like foo/**/bar (no leading **)
• ✅ Handles complex nested patterns correctly
• ✅ Maintains compatibility with existing maxDepth logic

Performance Impact

• Minimal: Single string check and substring operation
• No regression: Only affects the specific problematic patterns

Potential Concerns

1. Pattern complexity: The transformation creates brace expansion which could theoretically impact some file systems, but this is standard Java glob syntax
2. Documentation: Consider adding a note about this behavior in relevant documentation
3. Backwards compatibility: This change is additive - existing working patterns continue to work, and previously broken patterns now work correctly

Recommendations

✅ APPROVE - This is a well-implemented fix that:

• Solves the reported issue correctly
• Has comprehensive test coverage
• Uses efficient, readable code
• Maintains backward compatibility
• Follows Java glob conventions properly

The implementation is production-ready and addresses the core issue without introducing risks to existing functionality.

[pditommaso]

Closing since stating #6653 is not planned anymore