pathspec

In production, pathspec does exactly what it promises: efficiently matches file paths against gitignore-style patterns. Memory usage is minimal since it compiles patterns into regex once and reuses them. I've run it against directories with 100k+ files without noticeable performance degradation. The API is straightforward - create a PathSpec from patterns, call match_file() or match_files(), done.

The library is essentially stateless with no connection pooling concerns, which simplifies deployment. Error handling is predictable: invalid patterns raise clear exceptions at initialization rather than during matching, which is exactly what you want. No retry logic needed since operations are deterministic. The lack of logging hooks is noticeable though - when debugging why a file wasn't matched, you're instrumenting your own code or stepping through with a debugger.

Configuration is minimal by design - just pass your patterns and normalization options. Breaking changes between 0.x and 1.0 were well-documented. Timeout defaults aren't relevant here since pattern matching is synchronous and fast. Under load, it's CPU-bound for regex matching but scales linearly with file count.

In production, pathspec does exactly what it claims: matches file paths against gitignore-style patterns with minimal fuss. It's a pure Python implementation with no external dependencies, making it trivial to vendor or deploy. The API is straightforward - create a PathSpec from patterns, call match_file() or match_files(), done. Performance is consistent and predictable; we process thousands of paths against complex pattern sets without noticeable overhead.

The library handles edge cases well (nested directories, negation patterns, trailing slashes) and behavior matches git's actual .gitignore semantics closely. Error handling is minimal but appropriate - invalid patterns raise clear exceptions at initialization rather than silently failing during matching. Memory usage is reasonable; pattern compilation happens once and the compiled objects are lightweight.

One gotcha: there's no built-in caching or connection pooling because it's stateless pattern matching, but this simplicity is actually a strength. No background threads, no cleanup needed, no resource leaks. The library is effectively feature-complete and stable - breaking changes are extremely rare between versions. For file filtering pipelines or build tools, it just works reliably.

I've used pathspec extensively for implementing custom file filtering in build tools and security scanners. It does one thing well: matching file paths against gitignore-style patterns. The API is straightforward - you create a PathSpec from patterns and call match_file(). No surprises, which is exactly what you want for a utility library.

From a security perspective, this is a low-risk dependency. It's pure Python with no external dependencies beyond the standard library, eliminating supply chain concerns. Pattern parsing is deterministic and I haven't encountered issues with malicious patterns causing DoS or excessive resource consumption. Error handling is clean - invalid patterns raise clear exceptions that don't leak filesystem internals.

The main limitation is its narrow scope. It won't help with complex path traversal validation or canonicalization - you'll need os.path.realpath or pathlib for that. But for its intended use case of pattern matching, it's reliable and has been stable across versions.