fix(workbench): read the grafted closing span past a doubled marker - #2745
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zancas wants to merge 1 commit into
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fix(workbench): read the grafted closing span past a doubled marker#2745zancas wants to merge 1 commit into
zancas wants to merge 1 commit into
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Commit a6a973d gave zingolib/src/lightclient/sync.rs its own committed SYNC_SPAN markers, so on a modern arm the sync-ab graft now wraps an already instrumented launch and every session closes its span twice: the committed line bare, the grafted line carrying the output count. closing_span split the whole log on the close marker and examined the segment between the first two occurrences, which ends immediately before the grafted line and therefore never contains the count. The reader returned nothing forever, every modern arm burned its full 3600-second warm-up budget, and the comparison aborted while the session log looked healthy. The reader now takes its reading from the last complete line that carries both the close marker and the count, examining only text up to the final newline so a truncated line still yields no reading. Arms without committed markers, such as the zingolib_beta_ironwood tag, close once and are read as before. A falsifier test pins the doubled-close case. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Problem
Commit a6a973d added committed SYNC_SPAN markers to zingolib/src/lightclient/sync.rs. The sync-ab graft wraps that already instrumented launch. Each session therefore closes its span twice. The committed line is bare. The grafted line carries the output count.
closing_span split the whole log on the close marker. It examined only the segment between the first two occurrences. That segment never contains the count. The reader returned nothing forever. Every modern arm burned its full 3600-second warm-up budget. The comparison aborted while the session log looked healthy.
Fix
The reader now takes its reading from the last complete line that carries both the close marker and the count. It examines only text up to the final newline. A truncated line still yields no reading. Arms without committed markers close once and are read as before. A falsifier test pins the doubled-close case.
Verification
cargo check, clippy, and fmt are clean. The fixed rig completed two full A/B comparisons on 2026-08-25 with 0.05% and 0.00% output drift.
🤖 Generated with Claude Code