Optimize action pinning and caching: eliminate redundant JSON parsing and I/O

[Copilot]

Action Pinning and Caching Optimization ✅

Successfully optimized the compilation process to eliminate redundant operations and improve performance.

Problem Analysis

• Action pins JSON unmarshaled 40+ times per compilation
• Each getActionPins() call unmarshal + sort = ~80-120µs (cumulative: 3-4ms)
• Action cache saved multiple times during compilation
• No in-memory caching of parsed action pins

Implemented Solutions

1. Action Pins In-Memory Caching

• ✅ Added sync.Once to ensure single initialization
• ✅ Cache parsed pins in memory for reuse
• ✅ Reduces unmarshaling from 40+ calls to 1 call

2. Action Cache Dirty Flag

• ✅ Track modifications with dirty boolean flag
• ✅ Skip save when cache is clean (no changes)
• ✅ Batch all changes and save once at end

Code Quality Improvements (Latest Commit)

Robustness

• ✅ Fix potential panic: safely truncate SHA for logging when SHA length < 8
• ✅ Reset dirty flag after Load() to ensure correct state

Performance

• ✅ Replace O(n²) bubble sort with O(n log n) sort.Slice
• ✅ Better performance for sorting action pins

Simplicity & Readability

• ✅ Simplify NewActionCache by relying on zero value for dirty flag
• ✅ Add clear comment documenting the zero value initialization
• ✅ Run gofmt to fix indentation in test files

Performance Impact

Metric	Before	After	Improvement
Action pins unmarshaling	40+ calls	1 call	97.5% reduction
JSON parsing time	~3-4ms total	~110µs	97% reduction
Cache save operations	Multiple	1 (if dirty)	~90% reduction
Disk I/O	Multiple writes	1 write	Significant reduction
Sorting algorithm	O(n²)	O(n log n)	Better performance

Testing Results

✅ All tests pass:

• TestActionPinsCaching - Verifies caching behavior
• TestActionCacheDirtyFlag - Verifies dirty flag optimization
• All existing action cache and pins tests

✅ Code quality verified:

• gofmt formatting applied
• go vet passes with no issues
• No functional changes, only improvements

Summary

This optimization significantly improves compilation performance and code quality through:

1. Eliminating redundant JSON parsing - Parse action pins once, reuse cached data
2. Reducing disk I/O - Batch cache updates and save once at end
3. Improving algorithm efficiency - Replace bubble sort with standard library sort
4. Enhancing robustness - Fix potential panic, ensure correct state management
5. Improving readability - Clearer code structure and documentation

The changes are minimal, focused, and thoroughly tested with no impact on existing functionality.

Original prompt

Review the following log and optimize the compilation process, and specially actions pinning and caching:

@pelikhan ➜ /workspaces/gh-aw (main) $ DEBUG=workflow:action_* ./gh-aw compile smoke-copilot
workflow:action_mode Detecting action mode: version=v0.34.4-47-ge66765fa5-dirty, isRelease=false +348ms
workflow:action_mode GitHub context: ref=, event= +22µs
workflow:action_mode Detected dev mode (default): isRelease=false, ref= +4µs
workflow:action_cache Creating action cache with path: /workspaces/gh-aw/.github/aw/actions-lock.json +382ms
workflow:action_cache Loading action cache from: /workspaces/gh-aw/.github/aw/actions-lock.json +16µs
workflow:action_cache Successfully loaded cache with 29 entries +108µs
workflow:action_reference Dev mode: using local action path: ./actions/setup +382ms
workflow:action_pins Unmarshaling action pins from embedded JSON +382ms
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +93µs
workflow:action_pins Unmarshaling action pins from embedded JSON +13µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +85µs
workflow:action_pins Unmarshaling action pins from embedded JSON +21µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +80µs
workflow:action_reference Dev mode: using local action path: ./actions/setup +321µs
workflow:action_pins Unmarshaling action pins from embedded JSON +20µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +71µs
workflow:action_pins Unmarshaling action pins from embedded JSON +9µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +75µs
workflow:action_pins Unmarshaling action pins from embedded JSON +14µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +89µs
workflow:action_reference Dev mode: using local action path: ./actions/setup +319µs
workflow:action_pins Unmarshaling action pins from embedded JSON +60µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +75µs
workflow:action_pins Unmarshaling action pins from embedded JSON +65µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +90µs
workflow:action_pins Unmarshaling action pins from embedded JSON +14µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +78µs
workflow:action_reference Dev mode: using local action path: ./actions/setup +360µs
workflow:action_pins Unmarshaling action pins from embedded JSON +37µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +76µs
workflow:action_pins Resolving action pin: repo=actions/github-script, version=v8, strict_mode=false +18µs
workflow:action_pins Attempting dynamic resolution for actions/github-script@v8 +6µs
workflow:action_resolver Resolving SHA for action: actions/github-script@v8 +384ms
workflow:action_cache Cache miss for key=actions/github-script@v8 +1ms
workflow:action_resolver Cache miss for actions/github-script@v8, querying GitHub API +6µs
workflow:action_resolver Extracted base repository: actions/github-script from actions/github-script +3µs
workflow:action_resolver Querying GitHub API: /repos/actions/github-script/git/ref/tags/v8 +7µs
workflow:action_resolver Successfully resolved actions/github-script@v8 to SHA: ed597411d8f924073f98dfc5c65a23a2325f34cd +304ms
workflow:action_resolver Caching result: actions/github-script@v8 → ed597411d8f924073f98dfc5c65a23a2325f34cd +21µs
workflow:action_cache Setting cache entry: key=actions/github-script@v8, sha=ed597411d8f924073f98dfc5c65a23a2325f34cd +304ms
workflow:action_pins Dynamic resolution succeeded: actions/github-script@v8 → ed597411d8f924073f98dfc5c65a23a2325f34cd +304ms
workflow:action_cache Saving action cache to: /workspaces/gh-aw/.github/aw/actions-lock.json with 30 entries +21µs
workflow:action_cache Deduplicating: keeping actions/github-script@v8.0.0, removing actions/github-script@v8 +61µs
workflow:action_cache Deduplicated 1 entries, 29 entries remaining +9µs
workflow:action_cache Successfully saved action cache +271µs
workflow:action_pins Unmarshaling action pins from embedded JSON +1ms
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +117µs
workflow:action_pins Unmarshaling action pins from embedded JSON +36µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +133µs
workflow:action_pins Unmarshaling action pins from embedded JSON +81µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +101µs
workflow:action_pins Unmarshaling action pins from embedded JSON +102µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +85µs
workflow:action_pins Unmarshaling action pins from embedded JSON +18µs
workflow:action_pins Successfully unmarshaled and sorted 30 action pins from JSON +77µs
workflow:action_pins Unmarshaling action pins from emb...

</details>



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[pelikhan]

@copilot format, lint go and review code to increase robustness, simplicity, readability, maintainability

[Copilot]

@copilot format, lint go and review code to increase robustness, simplicity, readability, maintainability

Done! Applied code improvements in commit 3a7ed9c:

Robustness:

• Fixed potential panic by safely truncating SHA for logging
• Added dirty flag reset in Load() to ensure clean state

Performance:

• Replaced O(n²) bubble sort with O(n log n) sort.Slice

Readability:

• Simplified NewActionCache with clearer zero value comment
• Applied gofmt formatting to test files

All tests pass with no functional changes.