Fix 'meson introspect --target-files' for a custom target

[jon-turney]

Add testcase for, and fix meson introspect --target-files for a custom target, broken since 0.26.0 (PR #225)
For a CustomTarget, sources is a list of filenames as strings, not File objects.

Closes #2783

[jpakkane]

Thanks, but this is a leftover from the bad old days when everything was a string. The "correct" solution would be to convert custom target sources to Files with self.source_strings_to_files. Can you test if this patch works for you:

diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 31d7616c..820090fb 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -2448,6 +2448,8 @@ root and issuing %s.
         if len(args) != 1:
             raise InterpreterException('custom_target: Only one positional argument is allowed, and it must be a string name')
         name = args[0]
+        if 'input' in kwargs:
+            kwargs['input'] = self.source_strings_to_files(extract_as_list(kwargs, 'input'))
         tg = CustomTargetHolder(build.CustomTarget(name, self.subdir, self.subproject, kwargs), self)
         self.add_target(name, tg.held_object)
         return tg
@@ -3009,7 +3011,7 @@ different subdirectory.
             sources = [sources]
         for s in sources:
             if isinstance(s, (mesonlib.File, GeneratedListHolder,
-                              CustomTargetHolder, CustomTargetIndexHolder)):
+                              TargetHolder, CustomTargetIndexHolder)):
                 pass
             elif isinstance(s, str):
                 self.validate_within_subproject(self.subdir, s)
diff --git a/test cases/vala/9 gir/meson.build b/test cases/vala/9 gir/meson.build
index 1a09bec2..86de2c82 100644
--- a/test cases/vala/9 gir/meson.build 
+++ b/test cases/vala/9 gir/meson.build 
@@ -11,8 +11,8 @@ foo = shared_library('foo', 'foo.vala',
                      dependencies: [glib, gobject])
 
 custom_target('foo-typelib',
-              command: [g_ir_compiler, '--output', '@OUTPUT@', '@INPUT@'],
-              input: meson.current_build_dir() + '/Foo-1.0.gir',
+              command: [g_ir_compiler, '--output', '@OUTPUT@', meson.current_build_dir() + '/Foo-1.0.gir'],
+              input: [],
               output: 'Foo-1.0.typelib',
               depends: foo)

[dcbaker]

I have a few nits, but otherwise the test seems correct to me.

[jon-turney]

The "correct" solution would be to convert custom target sources to Files with self.source_strings_to_files. Can you test if this patch works for you:

Yes, that also works for custom targets in mesa.

I'm not sure about breaking vala/9 gir like that, though. Generating a typelib like that is documented, so that's just trading one regression for another...

[jpakkane]

This is my bad, I have been totally asleep at the wheel to accept that. Manually building paths to files is bad. We should never promote that in our tests or official docs. I really want to fix this properly, though, because this kind of string inconsistency is a big maintenance burden.

[jon-turney]

This is my bad, I have been totally asleep at the wheel to accept that. Manually building paths to files is bad. We should never promote that in our tests or official docs. I really want to fix this properly, though, because this kind of string inconsistency is a big maintenance burden.

Ok. This PR just contains the test case now (which currently fails in CI)

[nirbheek]

This is my bad, I have been totally asleep at the wheel to accept that. Manually building paths to files is bad.

Funnily enough, somehow I missed that too, so I share the blame.

[jon-turney]

Rebased to fix conflicts.

I added something to handle non-file inputs in a backwards compatble way, with a warning:

jon@tambora /meson/test cases/vala/9 gir
$ rm -r _build ; /meson/meson.py _build
[...]
WARNING: Custom target input '/meson/test cases/vala/9 gir/_build/Foo-1.0.gir' can't be converted to a File object.
This will become a hard error in the future.

This warning should probably say something more about what's probably wrong and how to remedy things.

Generating a typelib like that is documented

I guess a defect needs to be created about how vala libraries don't expose the .gir as an output, or something like that.

[jpakkane]

I created the bug as #4481.

[jon-turney]

I created the bug as #4481.

Thanks. Does this PR need anything further?