add builtin option to install licenses

Unless `meson.install_dependency_manifest()` is explicitly used, this
will cause a default implied one to be installed.

1 files changed, 12 insertions, 6 deletions

diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 843af5d..c676d13 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -1187,13 +1187,19 @@ class Backend:
         return outputs
 
     def generate_depmf_install(self, d: InstallData) -> None:
-        if self.build.dep_manifest_name is None:
-            return
+        depmf_path = self.build.dep_manifest_name
+        if depmf_path is None:
+            option_dir = self.environment.coredata.get_option(OptionKey('licensedir'))
+            assert isinstance(option_dir, str), 'for mypy'
+            if option_dir:
+                depmf_path = os.path.join(option_dir, 'depmf.json')
+            else:
+                return
         ifilename = os.path.join(self.environment.get_build_dir(), 'depmf.json')
-        ofilename = os.path.join(self.environment.get_prefix(), self.build.dep_manifest_name)
-        odirname = os.path.join(self.environment.get_prefix(), os.path.dirname(self.build.dep_manifest_name))
-        out_name = os.path.join('{prefix}', self.build.dep_manifest_name)
-        out_dir = os.path.join('{prefix}', os.path.dirname(self.build.dep_manifest_name))
+        ofilename = os.path.join(self.environment.get_prefix(), depmf_path)
+        odirname = os.path.join(self.environment.get_prefix(), os.path.dirname(depmf_path))
+        out_name = os.path.join('{prefix}', depmf_path)
+        out_dir = os.path.join('{prefix}', os.path.dirname(depmf_path))
         mfobj = {'type': 'dependency manifest', 'version': '1.0',
                  'projects': {k: v.to_json() for k, v in self.build.dep_manifest.items()}}
         with open(ifilename, 'w', encoding='utf-8') as f: