Expose the implementation language for external libraries

Ideally, all dependency objects should support this, but it's a lot of
work and isn't supported by all dependency types (like frameworks and
pkg-config), so for now just enable it for external libraries.

2 files changed, 13 insertions, 14 deletions

diff --git a/mesonbuild/dependencies.py b/mesonbuild/dependencies.py
index 39bf2b1..04a22f9 100644
--- a/mesonbuild/dependencies.py
+++ b/mesonbuild/dependencies.py
@@ -51,6 +51,7 @@ class DependencyMethods(Enum):
 class Dependency:
     def __init__(self, type_name, kwargs):
         self.name = "null"
+        self.language = None
         self.is_found = False
         self.type_name = type_name
         method = DependencyMethods(kwargs.get('method', 'auto'))
@@ -570,11 +571,12 @@ class ExternalProgram:
         return self.name
 
 class ExternalLibrary(Dependency):
-    # TODO: Add `lang` to the parent Dependency object so that dependencies can
-    # be expressed for languages other than C-like
-    def __init__(self, name, link_args=None, language=None, silent=False):
+    # TODO: Add `language` support to all Dependency objects so that languages
+    # can be exposed for dependencies that support that (i.e., not pkg-config)
+    def __init__(self, name, link_args, language, silent=False):
         super().__init__('external', {})
         self.name = name
+        self.language = language
         self.is_found = False
         self.link_args = []
         self.lang_args = []
@@ -582,9 +584,13 @@ class ExternalLibrary(Dependency):
             self.is_found = True
             if not isinstance(link_args, list):
                 link_args = [link_args]
-            if language:
-                self.lang_args = {language: link_args}
-            else:
+            self.lang_args = {language: link_args}
+            # We special-case Vala for now till the Dependency object gets
+            # proper support for exposing the language it was written in.
+            # Without this, vala-specific link args will end up in the C link
+            # args list if you link to a Vala library.
+            # This hack use to be in CompilerHolder.find_library().
+            if language != 'vala':
                 self.link_args = link_args
         if not silent:
             if self.is_found:
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index ed08987..0eb392d 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -982,14 +982,7 @@ class CompilerHolder(InterpreterObject):
         if required and not linkargs:
             l = self.compiler.language.capitalize()
             raise InterpreterException('{} library {!r} not found'.format(l, libname))
-        # If this is set to None, the library and link arguments are for
-        # a C-like compiler. Otherwise, it's for some other language that has
-        # a find_library implementation. We do this because it's easier than
-        # maintaining a list of languages that can consume C libraries.
-        lang = None
-        if self.compiler.language == 'vala':
-            lang = 'vala'
-        lib = dependencies.ExternalLibrary(libname, linkargs, language=lang)
+        lib = dependencies.ExternalLibrary(libname, linkargs, self.compiler.language)
         return ExternalLibraryHolder(lib)
 
     def has_argument_method(self, args, kwargs):