[debhelper-devel] Bug#895196: debhelper: The failing command on build hangs is no longer in the log

[Adrian Bunk]

Package: debhelper
Version: 11.1.5
Severity: important

https://buildd.debian.org/status/logs.php?pkg=prodigal&arch=armhf

The root cause of this FTBFS is that building training.c "hangs"
(6.5 hours build time exceed the 150m timeout, see #894473).

This bug is about debhelper (likely due to the #768791 change)
giving much worse logs for that on the buildds:

debhelper <= 11.1.4 (locally reproduced with 11.1.4):

...
gcc -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -pedantic -Wall -O3 -c -o training.o training.c
debian/rules:12: recipe for target 'build-arch' failed
make: *** [build-arch] Terminated
Makefile:40: recipe for target 'training.o' failed
make[1]: *** [training.o] Terminated
Build killed with signal TERM after 150 minutes of inactivity


debhelper >= 11.1.5 (locally reproduced with 11.1.5, 11.1.6, 11.2):

...
make[1]: Entering directory '/<<PKGBUILDDIR>>'
gcc -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -pedantic -Wall -O3 -c -o node.o node.c
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
E: Build killed with signal TERM after 150 minutes of inactivity


Note how using older debhelper results in exact information
where the problem is, while with newer debhelper the hanging
command is not even in the log.


This can be reproduced locally on amd64:
  dpkg-buildpackage -B  2>&1 | tee ../LOG.prodigal

Check whether the training.c compile is already printed before
the build "hangs" for a few minutes.


Another example:
  https://buildd.debian.org/status/logs.php?pkg=mame&arch=amd64

Despite several attempts noone has been able to reproduce why this
sometimes FTBFS, and it is not helpful that whatever hangs in the
build is likely not in the log.


If this is due to the "make -O" change as I suspect,
it should IMHO be reverted if this cannot be fixed.