Nirbheek/fix pkgconfig library dedup (#3813)

* Add a test case for bad de-dup of -framework args

https://github.com/mesonbuild/meson/issues/3800

* pkgconfig: Don't naively de-dup all arguments

Honestly don't know what I was smoking. Of course the `Libs:` field in
a pkg-config file can have arguments other than -l and -L

Closes https://github.com/mesonbuild/meson/issues/3800

* pkgconfig module: Fix needlessly aggressive de-dup

3 files changed, 22 insertions, 11 deletions

diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index 3bff0d2..8319cb7 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -589,9 +589,12 @@ class PkgConfigDependency(ExternalDependency):
         if ret != 0:
             raise DependencyException('Could not generate libs for %s:\n\n%s' %
                                       (self.name, out))
-        # These libraries should be safe to de-dup
-        link_args = OrderedSet()
+        link_args = []
+        # Library paths should be safe to de-dup
         libpaths = OrderedSet()
+        # Track -lfoo libraries to avoid duplicate work
+        libs_found = OrderedSet()
+        # Track not-found libraries to know whether to add library paths
         libs_notfound = []
         libtype = 'static' if self.static else 'default'
         # We always look for the file ourselves instead of depending on the
@@ -609,6 +612,9 @@ class PkgConfigDependency(ExternalDependency):
                 libpaths.add(lib[2:])
                 continue
             elif lib.startswith('-l'):
+                # Don't resolve the same -lfoo argument again
+                if lib in libs_found:
+                    continue
                 if self.clib_compiler:
                     args = self.clib_compiler.find_library(lib[2:], self.env,
                                                            list(libpaths), libtype)
@@ -618,10 +624,11 @@ class PkgConfigDependency(ExternalDependency):
                 else:
                     args = None
                 if args:
+                    libs_found.add(lib)
                     # Replace -l arg with full path to library if available
+                    # else, library is provided by the compiler and can't be resolved
                     if not args[0].startswith('-l'):
                         lib = args[0]
-                    # else, library is provided by the compiler and can't be resolved
                 else:
                     # Library wasn't found, maybe we're looking in the wrong
                     # places or the library will be provided with LDFLAGS or
@@ -645,10 +652,12 @@ class PkgConfigDependency(ExternalDependency):
                     raise DependencyException('Got a libtools specific "%s" dependencies'
                                               'but we could not compute the actual shared'
                                               'library path' % lib)
-                lib = shared_lib
                 self.is_libtool = True
-            link_args.add(lib)
-        self.link_args = list(link_args)
+                lib = shared_lib
+                if lib in link_args:
+                    continue
+            link_args.append(lib)
+        self.link_args = link_args
         # Add all -Lbar args if we have -lfoo args in link_args
         if libs_notfound:
             # Order of -L flags doesn't matter with ld, but it might with other
diff --git a/mesonbuild/modules/pkgconfig.py b/mesonbuild/modules/pkgconfig.py
index 68c2dc5..63d1109 100644
--- a/mesonbuild/modules/pkgconfig.py
+++ b/mesonbuild/modules/pkgconfig.py
@@ -170,16 +170,18 @@ class DependenciesHelper:
         return ', '.join(result)
 
     def remove_dups(self):
-        def _fn(xs):
+        def _fn(xs, libs=False):
             # Remove duplicates whilst preserving original order
             result = []
             for x in xs:
-                if x not in result:
+                # Don't de-dup unknown strings to avoid messing up arguments like:
+                # ['-framework', 'CoreAudio', '-framework', 'CoreMedia']
+                if x not in result or (libs and (isinstance(x, str) and not x.endswith(('-l', '-L')))):
                     result.append(x)
             return result
-        self.pub_libs = _fn(self.pub_libs)
+        self.pub_libs = _fn(self.pub_libs, True)
         self.pub_reqs = _fn(self.pub_reqs)
-        self.priv_libs = _fn(self.priv_libs)
+        self.priv_libs = _fn(self.priv_libs, True)
         self.priv_reqs = _fn(self.priv_reqs)
         self.cflags = _fn(self.cflags)
 
diff --git a/test cases/unit/33 external, internal library rpath/external library/meson.build b/test cases/unit/33 external, internal library rpath/external library/meson.build
index 0e9f443..6dcc97e 100644
--- a/test cases/unit/33 external, internal library rpath/external library/meson.build
+++ b/test cases/unit/33 external, internal library rpath/external library/meson.build
@@ -5,5 +5,5 @@ l = shared_library('faa_pkg', 'faa.c', install: true)
 
 pkg = import('pkgconfig')
 pkg.generate(name: 'faa_pkg',
-             libraries: l,
+             libraries: [l, '-framework', 'CoreFoundation', '-framework', 'CoreMedia'],
              description: 'FAA, a pkg-config test library')