linux-pam fails to link on master

[thesamesam]

$ git clone https://github.com/linux-pam/linux-pam
$ cd linux-pam && meson setup build && ninja -C build
[415/532] Linking target modules/pam_debug/tst-pam_debug-retval
FAILED: [code=1] modules/pam_debug/tst-pam_debug-retval
cc  -o modules/pam_debug/tst-pam_debug-retval modules/pam_debug/tst-pam_debug-retval.p/tst-pam_debug-retval.c.o -Wl,--as-needed -Wl,--no-undefined -pie -Wl,--fatal-warnings -Wl,--no-undefined-version -Wl,-O1 '-Wl,-rpath,$ORIGIN/../../libpam' -Wl,--start-group libpam_internal/libpam_internal.a libpam/libpam.so.0.85.1 -Wl,--end-group ''
/usr/lib/gcc/x86_64-pc-linux-gnu/16/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find : No such file or directory
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

8c6dc8d is the first bad commit:

commit 8c6dc8d9a2299acdb81c3d61e0265ce37be6210a (HEAD)
Author:     Dylan Baker <dylan@pnwbakers.com>
AuthorDate: Wed Dec 3 14:36:28 2025 -0800
Commit:     Dylan Baker <dylan@pnwbakers.com>
CommitDate: Mon Dec 8 10:08:42 2025 -0800

    build|interpreter: use typed_kwargs for BuildTarget(link_args)

 mesonbuild/build.py                     | 5 +----
 mesonbuild/interpreter/type_checking.py | 6 ++++++
 2 files changed, 7 insertions(+), 4 deletions(-)

cc @dcbaker

[thesamesam]

https://github.com/linux-pam/linux-pam/blob/f061ad4b8a3f8b8ae024885e1f7d4c64253634c4/modules/module-meson.build#L471-L498

[thesamesam]

meson.build:

project(
  'p',
  'c',
  version : '0.1',
)

exe = executable(
  'p',
  'p.c',
  link_args : '',
)

$ echo 'int main() {}' > p.c
$ meson setup build --wipe && ninja -C build
[2/2] Linking target p
FAILED: [code=1] p
cc  -o p p.p/p.c.o -Wl,--as-needed -Wl,--no-undefined ''
/usr/lib/gcc/x86_64-pc-linux-gnu/16/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find : No such file or directory
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

I think this use is reasonable, we document something like it at https://mesonbuild.com/Adding-arguments.html#per-target-arguments, and pam is just conditionally passing a blank string.

[dcbaker]

Gah, this is going to prove to be annoying to handle in general, since python treats ''.split() as [''], and I'm sure in some case of this we have people relying on that behavior, even though I think the more reasonable behavior is what linux-pam expects.

Nevermind, this is link_ags, still will be better with default()

I am now so close to getting all of the typing doing I can dust off my default() patches and make this all go away!

[bonzini]

I understand this is a regression, but why shouldn't an empty string become an empty argument? I would really prefer if supporting '' can be done only for meson_version < 1.10.0, libpam can use [] going forward.

[thesamesam]

Note that 1.10.0 is fine.