Use git_odb_exists instead of git_revparse_single for ObjectExists#2006
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Use git_odb_exists instead of git_revparse_single for ObjectExists#2006tyrielv wants to merge 1 commit into
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Replace the heavyweight git_revparse_single call in LibGit2Repo.ObjectExists with git_odb_exists, a purpose-built existence check that skips revparse expression parsing and git_object handle allocation. Benchmarked on an os.2020 enlistment (59.7M objects, 14 packs): - Existing objects: ~800 ns/op (comparable) - Missing objects: 1.3ms vs 2.8ms (2.1x faster) The ODB handle is lazily acquired on first ObjectExists call via git_repository_odb (returns the repo's internal ODB, ref-counted) and freed in Dispose. Falls back to revparse if ODB acquisition fails. Add ObjectCanBeParsed method that retains the old revparse behavior for callers that need corruption detection (LooseObjectsStep), since git_odb_exists only checks index presence, not object integrity. Assisted-by: Claude Opus 4.6 Signed-off-by: Tyrie Vella <tyrielv@gmail.com>
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Summary
Replaces the heavyweight
git_revparse_singlecall inLibGit2Repo.ObjectExistswithgit_odb_exists, a purpose-built existence check that skips revparse expression parsing andgit_objecthandle allocation.Benchmark (os.2020 enlistment, 59.7M objects, 14 packs)
Implementation
git_repository_odb,git_odb_exists,git_odb_free,git_oid_fromstrObjectExistscall, freed inDisposegit_revparse_singleif ODB handle acquisition failsSemantic split: ObjectExists vs ObjectCanBeParsed
git_odb_existsonly checks whether an OID is present in the object store -- it does not decompress or validate the object. This changes behavior forLooseObjectsStep.ClearCorruptLooseObjects, which relied onObjectExistsreturningfalsefor corrupt-but-present loose objects to trigger cleanup.To preserve that behavior, this PR introduces
ObjectCanBeParsed(sha)which retains the oldgit_revparse_singlepath for corruption detection.LooseObjectsStepis updated to callObjectCanBeParsedinstead ofObjectExists.ObjectExistsgit_odb_exists(fast)ObjectCanBeParsedgit_revparse_single(slow but validates)Impact
All
ObjectExistscallers benefit automatically:FindBlobsStage(blob prefetch)EnumerateMissingTreeEntries(diff/tree walk)CommitAndRootTreeExists(commit verification)LooseObjectsSteppreserves existing corruption-detection semantics viaObjectCanBeParsed.Files changed
LibGit2Repo.cs-- new P/Invokes,ObjectExistsusesgit_odb_exists, newObjectCanBeParsedGitRepo.cs-- exposeObjectCanBeParsedthrough the invokerLooseObjectsStep.cs-- callObjectCanBeParsedinstead ofObjectExists