perf: skip PreprocessLinkSubstitutions when no {{ }} present - #3837
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The MatchEvaluator callback only rewrites links whose URL contains {{ }}.
Across the 435k-file corpus only a small fraction of files use attribute
substitutions, so both GetCodeBlockRanges (a full span scan) and the
Regex.Replace (allocates a new string + a Match+Group per link) were
dead work on the vast majority of files.
Adding an early-return guard eliminates both allocations for every file
that does not contain {{ at all.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
reakaleek
approved these changes
Aug 12, 2026
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Summary
PreprocessLinkSubstitutionsunconditionally runsGetCodeBlockRanges(a full span scan) andRegex.Replace(allocates a new string + aMatch+Groupobject per link) on every markdown file. The callback only rewrites links whose URL contains{{; on a corpus where the vast majority of files have no attribute substitutions at all, both operations are pure overhead.Adding an early-return guard eliminates both allocations for every file that does not contain
{{.Test plan
dotnet test tests/Elastic.Markdown.Tests/ --filter SubstitutionTest|MutationOperatorsInLinksTest— 7 tests pass (covers the link-substitution path)dotnet test tests/Elastic.Markdown.Tests/— full 1951-test suite passesdotnet run --project src/tooling/docs-migrate -- bench— recordResolveDirectoryTreetime🤖 Generated with Claude Code