misc/android: improve exit code workaround
go_android_exec gets the exit status of the process run inside the
Android emulator by sending a small shell script that runs the desired
command and then prints "exitcode=" followed by the exit code. This is
necessary because adb does not reliably pass through the exit status
of the subprocess.
An old bug about this
(https://code.google.com/p/android/issues/detail?id=3254) was closed
in 2016 as fixed in Android N (7.0), but it seems that the adb on the
Android builder at least still sometimes fails to pass through the
exit code.
Unfortunately, this workaround has the effect of injecting
"exitcode=N" into the output of the subprocess it runs, which messes
up tests that are looking for golden output from a subprocess.
Fix this by inserting a filter Writer that looks for the final
"exitcode=N" and strips it from the exec wrapper's own stdout.
For #15919.
This will help us in cleaning up "host tests" for #37486.
Change-Id: I9859f5b215e0ec4a7e33ada04a1857f3cfaf55ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/488975
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>