Print warning if using "default_options" without a "fallback".defargwarn

1 files changed, 2 insertions, 0 deletions

diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 6fef4a90a..d5d2f7e33 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -3039,6 +3039,8 @@ external dependencies (including libraries) must go to "dependencies".''')
 
     def dependency_impl(self, name, display_name, kwargs):
         disabled, required, feature = extract_required_kwarg(kwargs, self.subproject)
+        if'default_options' in kwargs and 'fallback' not in kwargs:
+            mlog.warning('The "default_options" keyworg argument does nothing without a "fallback" keyword argument.')
         if disabled:
             mlog.log('Dependency', mlog.bold(display_name), 'skipped: feature', mlog.bold(feature), 'disabled')
             return DependencyHolder(NotFoundDependency(self.environment), self.subproject)