Reading the package list with `mapfile < file` has unambiguous line
semantics. Routing it through a step output and a here-string instead
would append an extra empty array element if the value ever carried a
trailing newline, and that element would reach go test as an empty
package argument. The step output now carries only a single-line boolean,
and the list travels through RUNNER_TEMP. An explicit empty-entry guard
fails closed if the file is ever malformed.
This job cannot execute on its own pull request — editing a workflow
routes the revision to full_suite, which skips the focused path — so the
implementation deliberately avoids depending on platform-specific
trailing-newline behavior that local verification cannot observe.
chichuan
308e71c783