BuildTestEmbedded local test builds can compile changed workspace source successfully but then

Reported (UTC): 2026-07-13 20:06

BuildTestEmbedded local test builds can compile changed workspace source successfully but then execute a stale artifact with the same Maven version from ~/.cache/coursier/v1/bldbinary/repository. In /code/BuildTestEmbedded-task19, after changing BuildWatchdog.loop and deleting the documented ~/.aibuildcaches/_code_BuildTestEmbedded-task19 directory, scripts/test.bash logged 'buildtest.embedded.buildMaven() (succeeded in 57945ms)' and showed compilation of the modified source, but the child test classpath resolved /home/leslie/.cache/coursier/v1/bldbinary/repository/buildtest/embedded/buildtest-embedded/0.0.276/buildtest-embedded-0.0.276.jar with an old 2026-07-13 16:45 mtime. javap proved its loop bytecode went directly from runOneCheck() to clockSleep() and omitted the newly compiled if (!running) break. Impact: deterministic product-fix tests falsely fail against stale bytecode even after following the repository's documented project-cache clear. Workaround: remove the exact local bldbinary coordinate directory as well as the project .aibuildcaches directory before rebuilding. Durable fix: local build-rule artifact resolution should return/use the newly built File directly or atomically replace/version its bldbinary coordinate; the test launcher must not prefer an existing same-version cached artifact over the current workspace build.

Production verification — 2026-07-17

Status: STILL EXISTS. Current production remains degraded rather than retired: buildtest.kotlin.build returned HTTP 200 but took 8.89 seconds, while the production host showed load average 60.59, CPU pressure near 90%, and the BuildTest JVM at about 1.8 GiB RSS.

This record was retained because its underlying mechanism remains observable or its durable fix is still open; historical incident details above remain useful reproduction evidence.