fix: stop find_nearest_bookmarked_ancestors re-walking merge ancestors combinatorially (RIG-3585) - #5
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…s combinatorially (RIG-3585) `find_nearest_bookmarked_ancestors` recursed with no visited set, re-expanding a shared ancestor once per path that reaches it — one `jj log` subprocess per visit. On a history with merge commits outside `trunk()` this is exponential in the number of merges: a 12-rung merge ladder spawns 8194 `jj` invocations and a real 136-commit / 26-merge repo did not terminate in 200s. Thread a `visited` set (keyed on commit id) through the recursion so each commit is expanded at most once. The set of boundary ancestors is unchanged — a boundary found on the first visit already bubbles to the root and the caller deduplicates via `BTreeSet` — so the walk becomes linear with identical output. A test-only `jj` subprocess counter on `Jujutsu` backs a regression test asserting the invocation count stays linear over a 12-rung merge ladder (8194 without the fix, well under 200 with it). Spec-impact: none. Refs RIG-3585 Co-authored-by: Matt Wilkinson <matt@rigel.build>
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find_nearest_bookmarked_ancestorsrecursed with no visited set, re-expanding a shared ancestor once per path that reaches it — onejj logsubprocess per visit. On a history with merge commits outsidetrunk()this is exponential in the number of merges: a 12-rung merge ladder spawns 8194jjinvocations and a real 136-commit / 26-merge repo did not terminate in 200s.Thread a
visitedset (keyed on commit id) through the recursion so each commit is expanded at most once. The set of boundary ancestors is unchanged — a boundary found on the first visit already bubbles to the root and the caller deduplicates viaBTreeSet— so the walk becomes linear with identical output. A test-onlyjjsubprocess counter onJujutsubacks a regression test asserting the invocation count stays linear over a 12-rung merge ladder (8194 without the fix, well under 200 with it).Spec-impact: none. Refs RIG-3585
Co-authored-by: Matt Wilkinson matt@rigel.build