Stop build on custom_target errors

[voidtrance]

I have a custom_target() defined as part of my build. What I've noticed is that the build does not error out if the script executed by the custom_target() exits with a non-zero exit status.

Does custom_target() ignore the command exit status or am I doing something wrong?

[dcbaker]

How far does it go past that? Ninja will stop scheduling new jobs when something fails, but it doesn't stop currently running jobs.

[voidtrance]

The custom_target() generates a header file that is a pre-requisite for a library() object. The script that is being executed by custom_target() fails at some point and the generated header file is "invalid" (it's missing an #endif).

The error that I see is that the library() compilation fails due to the malformed header file.

[eli-schwartz]

How do you know the script fails? The fact that it produces a malformed, invalid header file doesn't actually mean the script failed.

[dcbaker]

That sounds like the generator is returning 0 even though it's failing to generate a valid header.

[voidtrance]

The malformed header file is malformed because it is incomplete. It's incomplete because the script exited early. I ran it manually and confirmed that it does exit early with a non-zero exit status.

From Meson:

     [21/46] Compiling C object src/core/_vortex_core.cpython-313-x86_64-linux-gnu.so.p/core.c.o
      FAILED: src/core/_vortex_core.cpython-313-x86_64-linux-gnu.so.p/core.c.o
      cc -Isrc/core/_vortex_core.cpython-313-x86_64-linux-gnu.so.p -Isrc/core -I../../src/core -Isrc/include -I../../src/include -Isrc/core/kinematics -I../../src/core/kinematics -Isrc/lib -I../../src/lib -Isrc/threads -I../../src/threads -Isrc/lib/atomics -I../../src/lib/atomics -Isrc/lib/logging -I../../src/lib/logging -Isrc/core/objects -I/usr/include/python3.13 -fvisibility=hidden -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -O0 -g -DCACHELINE_SIZE=64 -Wunused -DVORTEX_DEBUG -g -fPIC -MD -MQ src/core/_vortex_core.cpython-313-x86_64-linux-gnu.so.p/core.c.o -MF src/core/_vortex_core.cpython-313-x86_64-linux-gnu.so.p/core.c.o.d -o src/core/_vortex_core.cpython-313-x86_64-linux-gnu.so.p/core.c.o -c ../../src/core/core.c
      In file included from ../../src/core/core.c:40:
      src/core/objects/vobj_defs.h:19: error: unterminated #ifndef
         19 | #ifndef __VOBJ_DEFS_H__
      In file included from ../../src/core/core.c:41:
      ../../src/core/objects/axis.h:25:1: error: expected specifier-qualifier-list before ‘typedef’
         25 | typedef struct {
            | ^~~~~~~
      [22/46] Generating symbol file src/core/kinematics/libkinematics.so.p/libkinematics.so.symbols

And from running the script manually:

# python3 ./tools/generate_vobj_defs.py --root . v.h
# echo $?
255

[eli-schwartz]

When you say the build doesn't error out, you mean ninja completes and echo $? says it returned zero for success? This is absolutely a problem with the script that ninja runs not actually correctly exiting 1 for errors.

[voidtrance]

No, see above response as to what happens. It's actually ninja that fails during compilation of a library() object.