Performance Optimizations and Test Suite

[wiggin77]

Summary

This PR lays the groundwork for the upcoming tag-based filtering system (see docs/TAGGING-DESIGN.md) by implementing critical performance optimizations and comprehensive test coverage.

Performance Optimizations (~3-4x improvement: 640ns → 200ns per log call)

• Switch to sync.Map level cache as default (lock-free reads vs mutex-protected array)
• Add per-target level caching to eliminate redundant filter checks during fanout (target.go:51,67,141-153)
• Optimize shouldQuote() with early-exit logic (formatter.go:154-157)
• Fix nil panic in syncMapLevelCache.get() (levelcache.go:37-40)

Bug Fixes

• Fix ResetLevelCache() lock ordering to prevent deadlocks (logr.go:233-246)
• Ensure per-target caches are cleared when global cache resets

Comprehensive Test Suite (3,900+ lines, 85+ new tests)

• bufferpool_test.go (369 lines) - Buffer pool reuse, concurrency, memory leaks
• concurrent_test.go (543 lines) - Concurrent logging, flushing, target management
• errorhandling_test.go (267 lines) - Invalid fields, queue overflow, shutdown
• filter_test.go (242 lines) - Custom filters, level boundaries, mixed filters
• islevelenabled_test.go (398 lines) - Cache behavior, level checks
• levelcache_test.go (310 lines) - Cache invalidation, concurrency, backward compatibility
• loggerwith_test.go (269 lines) - WithFields, structured logging, context propagation
• logm_test.go (363 lines) - Multi-level logging, mixed filters
• queue_test.go (428 lines) - Queue overflow, concurrent operations, flush behavior
• Enhanced benchmarks with realistic multi-tag scenarios (test/bench_test.go)

Documentation & Tooling

• Add docs/OPTIMIZATIONS.md - Performance analysis and cache improvements
• Add docs/TAGGING-DESIGN.md - Future tag-based filtering system design
• Add logr-config-schema.json - Configuration validation schema
• Add .golangci.yml and Makefile for linting and build automation

Ticket Link

NONE

[Copilot]

Pull Request Overview

This PR implements performance optimizations and adds a comprehensive test suite for the logging system as groundwork for an upcoming tag-based filtering system. The changes focus on making the sync.Map level cache the default, adding per-target caching, and optimizing string quoting logic for better performance.

Key changes:

• Switch from arrayLevelCache to syncMapLevelCache as default for better performance with sparse level IDs
• Add per-target level caching to eliminate redundant filter checks during fanout operations
• Optimize shouldQuote() function with early-exit logic for faster string processing

Reviewed Changes

Copilot reviewed 34 out of 34 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
options.go	Changes cache defaults and updates option naming for backward compatibility
logr.go	Implements cache default switch and improves cache invalidation with lock ordering
target.go	Adds per-target level caching infrastructure
formatter.go	Optimizes shouldQuote() function with early-exit boolean logic
levelcache.go	Fixes potential nil panic in syncMapLevelCache.get()
test files	Adds comprehensive test coverage across multiple scenarios
config files	Adds configuration schema, documentation, and build automation

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Unit Test Results

351 tests  +245   351 ✔️ +245   1m 4s ⏱️ +36s
  10 suites ±    0       0 💤 ±    0 
    1 files   ±    0       0 ❌ ±    0 

Results for commit a568979. ± Comparison against base commit 11788d8.

♻️ This comment has been updated with latest results.