perf: reduce ValidScopedCSSClass save latency on large themes#1181
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perf: reduce ValidScopedCSSClass save latency on large themes#1181
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Moves per-file CSS class extraction onto the language server's AugmentedLiquidSourceCode so it is memoized per file version and invalidated automatically when a document changes. Eliminates the full-theme rescan that ran on every save. Also skips syntax-tree parsing for Liquid files with no stylesheet tag, cutting first-save and CLI-run costs. Re-enables ValidScopedCSSClass in the recommended config, reversing the temporary opt-out from #1180. Fixes #1179.
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Summary
Fixes the save-lag reported in #1179 and re-enables
ValidScopedCSSClassin the recommended config (reversing the temporary opt-out from #1180).What was happening
The check needed to know every CSS class declared anywhere in the theme to avoid false positives on CDN/utility classes. The language server was rebuilding that information from scratch on every save — re-reading and re-parsing every Liquid file with a stylesheet tag, even though the language server already holds the parsed syntax tree for every file in memory.
What this PR changes
Two architectural changes, no change to the check's output or public API:
CSS class extraction is now a memoized derivation on the language server's document model — alongside schema and doc-definition extraction, following the same pattern. When a document changes, the model replaces the cached extraction automatically, so invalidation is implicit. The expensive parse work is shared across every consumer of a file's CSS classes and across every save within a session.
Early exit for files with no stylesheet tag — cheap source-level scan avoids invoking the syntax-tree parser for files that cannot declare CSS classes.
Impact (measured on a 240-file theme)
Test plan
main; subsequent saves sub-second (see logs)🤖 Generated with Claude Code