Under `mvn -T<n>` with the three yarn-using modules (ui-ngx,
msa/web-ui, msa/js-executor), concurrent yarn 1.x processes contend
on the shared `~/.cache/yarn`. The `--mutex network` flag was applied
only to `yarn install`, so `yarn run pkg` could overlap with another
module's install. Intermittent failures observed on CI:
`/bin/sh: 1: tsc: not found` during `yarn run pkg`, caused by
incomplete typescript extraction into per-module node_modules.
Fix at two layers:
1. Maven reactor chain (primary): add reactor-only pom <dependency>
entries (type=pom, scope=provided, wildcard exclusions) to form
ui-ngx -> msa/web-ui -> msa/js-executor
so the MultiThreadedBuilder schedules them strictly serial,
regardless of -T thread count. msa/web-ui already had a real
dependency on ui-ngx; only one new fake link was needed.
2. Yarn-level mutex (defense in depth): add `--mutex network` to
`yarn run pkg` (msa/web-ui, msa/js-executor) and
`yarn run build:prod` (ui-ngx), so single-module builds outside the
reactor chain (`mvn -pl msa/<module>`) still serialize against any
other yarn process on the agent.
Comment in msa/pom.xml updated: the previous "Modules order is
important..." note was misleading - module order in the reactor does
not enforce serialization under -T; the dependency edges do.
Sergey Matvienko
fd4a5b36f6