options: subproject system options require the global ones

Because system options apply to all subprojects, they need to be
present globally whenever a subproject needs them.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 20 insertions, 0 deletions

diff --git a/mesonbuild/options.py b/mesonbuild/options.py
index 2226e6bf0..62413b1a7 100644
--- a/mesonbuild/options.py
+++ b/mesonbuild/options.py
@@ -899,6 +899,12 @@ class OptionStore:
 
         self.options[key] = valobj
         pval = self.pending_options.pop(key, None)
+        if key.subproject:
+            proj_key = key.evolve(subproject=None)
+            self.add_system_option_internal(proj_key, valobj)
+            if pval is None:
+                pval = self.options[proj_key].value
+
         if pval is not None:
             self.set_option(key, pval)
 
diff --git a/unittests/optiontests.py b/unittests/optiontests.py
index 3b3ffc98e..5ed601fed 100644
--- a/unittests/optiontests.py
+++ b/unittests/optiontests.py
@@ -35,6 +35,20 @@ class OptionTests(unittest.TestCase):
         optstore.initialize_from_top_level_project_call({OptionKey('someoption'): new_value}, {}, {})
         self.assertEqual(optstore.get_value_for(k), new_value)
 
+    def test_subproject_system_option(self):
+        """Test that subproject system options get their default value from the global
+           option (e.g. "sub:b_lto" can be initialized from "b_lto")."""
+        optstore = OptionStore(False)
+        name = 'someoption'
+        default_value = 'somevalue'
+        new_value = 'new_value'
+        k = OptionKey(name)
+        subk = k.evolve(subproject='sub')
+        optstore.initialize_from_top_level_project_call({}, {}, {OptionKey(name): new_value})
+        vo = UserStringOption(k.name, 'An option of some sort', default_value)
+        optstore.add_system_option(subk, vo)
+        self.assertEqual(optstore.get_value_for(subk), new_value)
+
     def test_parsing(self):
         with self.subTest('subproject'):
             s1 = OptionKey.from_string('sub:optname')