ninja clean fails when a target is defined with the same name as a directory

[keszybz]

I get the following error:

$ ninja-build clean
[2/2] 'Cleaning'
FAILED: clean 
'ninja-build' '-t' 'clean'
ninja: error: remove(man): Directory not empty
Cleaning... 1 files.
ninja: build stopped: subcommand failed.

$ ls -lG man/
total 8
-rw-rw-r--. 1 zbyszek  404 Apr 19 11:13 custom-entities.ent
drwxrwxr-x. 2 zbyszek 4096 Apr 19 11:13 rules/

So the man directory should not be removed at all, for two reasons: 1. there's a subdir, 2. there's a generated file. I don't know why clean tries to remove it.

I tried to make simple test case, but I couldn't reproduce the error. So it's something in the way that man is defined...

[keszybz]

OK, now I get it:

==> meson.build <==
project('clean1', 'c')
conf = configuration_data()
subdir('sub1')

==> sub1/meson.build <==
configure_file(
        output : 'config.h',
        configuration : conf)
run_target('sub1',
           command : ['echo'])

$ nj clean
[1/1] 'Cleaning'
FAILED: clean 
'ninja-build' '-t' 'clean'
ninja: error: remove(sub1): Directory not empty
Cleaning... 0 files.
ninja: build stopped: subcommand failed.

[QuLogic]

The name of the run target is the "output" of the build statement and ninja cleans things based on build outputs, so... I'm not sure how to express this in ninja.

[QuLogic]

Maybe run targets should depend on the phony rule instead of the made-up CUSTOM_COMMAND, since they aren't producing any outputs?

[nirbheek]

This is also a problem for libgxps and nautilus which have a directory called test. The same problem also happens if you define a directory called benchmark.

[nirbheek]

Maybe run targets should depend on the phony rule instead of the made-up CUSTOM_COMMAND, since they aren't producing any outputs?

Can't use phony because that means the target is an alias for some other target and if you don't specify some other target it means that it does nothing. The COMMAND = line will get ignored in either case.

What we could do, to work around this Ninja bug, is to define targets called meson-test, meson-benchmark, and meson-RUN_TARGET_NAME which do the actual work, and have test, benchmark, RUN_TARGET_NAME as aliases for that with phony. I've tested it and it does work:

build meson-test: CUSTOM_COMMAND all PHONY
 COMMAND = /usr/bin/python3 -u /home/nirbheek/projects/repositories/github/meson.git/mesontest.py --no-rebuild --print-errorlogs
 DESC = Running$ all$ tests.
 pool = console

build test: phony meson-test

However, simultaneously we should try to fix this in Ninja too.

[jpakkane]

The test target is tagged phony and it works just fine (just runs a command). Marking run targets with PHONY should work.

I just tested by creating a directory called test in a build dir and running ninja test. It works as it should.

[nirbheek]

I just tested by creating a directory called test in a build dir and running ninja test. It works as it should.

That's not the problem. The problem is that ninja clean fails if you define any targets inside a directory called test (or benchmark or any other CUSTOM_COMMAND target).

[nirbheek]

FWIW, the upstream bug for the general problem of not recursively deleting directories on non-Windows platforms is ninja-build/ninja#828.

[jpakkane]

Okay, let's put in the workaround with a link to that bug.