Fix return type of debugfile functions

It was returning None in some cases while being marked as returning
string.

2 files changed, 3 insertions, 3 deletions

diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 4cbdb1f..cb8eae5 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -921,7 +921,7 @@ class Compiler(HoldableObject, metaclass=abc.ABCMeta):
     def get_compile_debugfile_args(self, rel_obj: str, pch: bool = False) -> T.List[str]:
         return []
 
-    def get_link_debugfile_name(self, targetfile: str) -> str:
+    def get_link_debugfile_name(self, targetfile: str) -> T.Optional[str]:
         return self.linker.get_debugfile_name(targetfile)
 
     def get_link_debugfile_args(self, targetfile: str) -> T.List[str]:
diff --git a/mesonbuild/compilers/mixins/islinker.py b/mesonbuild/compilers/mixins/islinker.py
index 711e3e3..cfdd746 100644
--- a/mesonbuild/compilers/mixins/islinker.py
+++ b/mesonbuild/compilers/mixins/islinker.py
@@ -120,8 +120,8 @@ class BasicLinkerIsCompilerMixin(Compiler):
     def get_buildtype_linker_args(self, buildtype: str) -> T.List[str]:
         return []
 
-    def get_link_debugfile_name(self, targetfile: str) -> str:
-        return ''
+    def get_link_debugfile_name(self, targetfile: str) -> T.Optional[str]:
+        return None
 
     def thread_flags(self, env: 'Environment') -> T.List[str]:
         return []