Move caching into SourceTransformingLoader, remove CachingTransformer

[lisachenko]

Summary

Follow-up to the boot-time series (#589, #591, #592, #593, #594), as requested: CachingTransformer is removed and the caching logic lives right in SourceTransformingLoader::filter(), next to the StreamMetaData construction. If a usable cache record exists for the streamed file, its content is returned from there as the result — otherwise the code falls back to transformCode().

What changed

• SourceTransformingLoader::filter() decides in this order:
  1. Guard — no cache path, or cache path equals the original file: the source passes through untouched (previously the RESULT_ABORTED branch of the wrapper).
  2. Cache hit (findCachedContent()) — the cached file content (or, for a known-untransformed file, the buffered original source) is emitted as-is: no StreamMetaData, no parsing, no transformer is ever constructed. All freshness rules are ported verbatim: filemtime comparison, recorded-cacheUri match, hasAnyResourceChangedSince(), and the PREBUILT_CACHE trusted-record short-circuit.
  3. Cache miss — parse into StreamMetaData, run the transformer chain, persist via saveToCache() (ported verbatim: __AopProxied suffix rename, mkdir/LOCK_EX/chmod, setCacheState() with the class-map recording from perf(cache): split runtime include map from transformation metadata #594 intact).
• transformCode() now returns the overall TransformerResultEnum (the logic formerly in CachingTransformer::processTransformers()); the chain is assembled lazily on the first miss from the tagged container services (getServicesByInterface(SourceTransformer::class)), so no unset() exclusion is needed anymore.
• Removed src/Instrument/Transformer/CachingTransformer.php, its container definition in AspectKernel::init(), and SourceTransformingLoader::addTransformer(). The registerTransformerServices() extension hook is unchanged.

Why it helps

The old cached branch went through the whole filter pipeline anyway and then re-parsed the cached file (ReflectionEngine::parseFile()) just to rebuild the token stream. Now a hit skips parsing entirely — which finally makes the warm-cache fast path apply in debug mode too, with unchanged invalidation semantics.

Local numbers (fixture app, opcache file cache, median of 21):

Mode (PHP 8.5)	master	this PR	Δ
debug warm boot+request	15.1–16.2 ms	5.7–6.0 ms	−62 %
debug warm files included	187	127	−60 files
production warm	3.9 ms	3.9 ms	unchanged
cold (first boot)	~103 ms	~103 ms	unchanged

PHP 8.4 debug warm shows the same shape: 16.2 ms → 5.5 ms (−66 %).

Validation

• phpunit green on PHP 8.5 and 8.4 (2486 tests), including the functional warmup / debug:weaving / inconsistent-weaving coverage that exercises the moved logic on real caches
• phpstan (level max) clean

🤖 Generated with Claude Code

https://claude.ai/code/session_01V1Z87HZ2iz23WPTtTYqFxE

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Generated by Claude Code

[lisachenko]

i do not see any tests here - please cover with tests

[lisachenko]

Added in fd84b7e: tests/Instrument/ClassLoading/SourceTransformingLoaderTest.php covers every branch of the filter's cache decision through the real stream filter (php://filter/read=.../resource=...), in separate processes because of the loader's static state:

• fresh transformed record → cached file content served, getServicesByInterface() never called (no transformer constructed)
• fresh untransformed record → original source served, same no-transformer guarantee
• miss → chain runs, woven file written, cache state recorded with its cacheUri
• stale record (older than the source) → falls back to the chain
• abstaining chain → recorded as untransformed, no cache file written
• aborting transformer → rest of the chain skipped, nothing written
• PREBUILT_CACHE → deliberately stale record trusted, hasAnyResourceChangedSince() never consulted
• guard (cache path == original file) → source passes through untouched, no transformers, no state written

Full suite green on PHP 8.5/8.4 (2494 tests), PHPStan clean.

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Generated by Claude Code