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[perf] Skip unused-import name resolution when the node has no use statement - #8701
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…atement UnusedImportRemovingPostRector::enterNode() fires for both the FileNode root and the inner Namespace_. To find which imports are unused it resolves every referenced name via two full-AST traversals (findNonUseImportNames + findNamesInDocBlocks), and that resolution is not cached. In a namespaced file the `use` statements live inside the Namespace_, so the FileNode-level call did the full double walk and then found no `use` statement to act on - pure waste. Add a cheap guard: if the node has no direct `use` statement there is nothing to remove, so return before the resolution walks. Behavior is unchanged (non-namespaced files keep their `use` at FileNode level and still resolve). Adds bench/unused_import_removing_bench.php.
This was referenced Oct 18, 2026
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Why
To drop unused
useimports,UnusedImportRemovingPostRector::enterNode()resolves every name referenced in the file via two full-AST traversals (findNonUseImportNames()+findNamesInDocBlocks()), and that resolution is not cached.enterNode()fires for both theFileNoderoot and the innerNamespace_. In a namespaced file theusestatements live inside theNamespace_, so theFileNode-level call did the full double walk and then found nousestatement to act on - pure wasted work, on every post-rector pass.What
Add a cheap guard: if the node has no direct
usestatement, there is nothing to remove, so return before the resolution walks. Behavior is unchanged - non-namespaced files keep theiruseatFileNodelevel and still resolve.Bench
Adds
bench/unused_import_removing_bench.php, which drives the realenterNode()on the root nodes a file actually hits (FileNode + Namespace_). Measured onbench/Source/ManyNamesSource.php(namespaced, all imports used), 40 repeats x 400 enters:~2x on a namespaced file - the wasted FileNode-level double walk is gone.
Tests
rules-tests/CodingStyle,tests/Issues(incl.NamespacedUse,NoNamespaced,NamespacedUseAutoImport), and the Import/UnusedImport filters all green. ECS and PHPStan level 8 clean.