Fix dead map identity comparison in dyn.Value.eq#5525
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The KindMap branch compared addresses of the receiver's local copies, which is never true, so visit rebuilt ancestor maps on every visited path even when nothing changed. Compare the mapping's backing pairs slice instead, mirroring the KindSequence branch. Co-authored-by: Isaac
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Commit: efabb30
22 interesting tests: 15 SKIP, 7 KNOWN
Top 28 slowest tests (at least 2 minutes):
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Why
Found during a full-repo review of the CLI.
dyn.Value.eqis the no-change short-circuit used bylibs/dyn/visit.go: when a transform returns a value unchanged, the visit returns the original parent instead of rebuilding it. The map branch compared&v.v == &w.von value receivers, which takes the addresses of two local copies and is never true. The short-circuit was dead for maps, so every visited path cloned its ancestor maps even when nothing changed. This is wasted allocation only; correctness was unaffected.Changes
Before,
eqalways reported two map values as different; now it reports them as equal when they share the same underlying mapping. TheKindMapbranch compares the identity of the mapping's backing pairs slice (first-element pointer, with the same empty and length checks), mirroring the existingKindSequencebranch.Added unit tests for the map cases of
eqand a visit-level test asserting that an identity transform does not rebuild ancestor maps. Both fail against the previous implementation.Test plan
go test ./libs/dyn/...passes./task fmt-q, golangci-lint onlibs/dyn(0 issues), and./task checkspassThis pull request and its description were written by Isaac.