Add UserFeatureOption type

This is a special type of option to be passed to most 'required' keyword
arguments. It adds a 3rd state to the traditional boolean value to cause
those methods to always return not-found even if the dependency could be
found.

Since integrators doesn't want enabled features to be a surprise there
is a global option "auto_features" to enable or disable all
automatic features.

1 files changed, 8 insertions, 0 deletions

diff --git a/mesonbuild/optinterpreter.py b/mesonbuild/optinterpreter.py
index 4207f45..cd3139b 100644
--- a/mesonbuild/optinterpreter.py
+++ b/mesonbuild/optinterpreter.py
@@ -116,11 +116,19 @@ def string_array_parser(name, description, kwargs):
                                     choices=choices,
                                     yielding=kwargs.get('yield', coredata.default_yielding))
 
+@permitted_kwargs({'value', 'yield'})
+def FeatureParser(name, description, kwargs):
+    return coredata.UserFeatureOption(name,
+                                      description,
+                                      kwargs.get('value', 'enabled'),
+                                      yielding=kwargs.get('yield', coredata.default_yielding))
+
 option_types = {'string': StringParser,
                 'boolean': BooleanParser,
                 'combo': ComboParser,
                 'integer': IntegerParser,
                 'array': string_array_parser,
+                'feature': FeatureParser,
                 }
 
 class OptionInterpreter: