Allow deprecating an option for a new one

2 files changed, 18 insertions, 4 deletions

diff --git a/mesonbuild/coredata.py b/mesonbuild/coredata.py
index cf06ac6..b9a4828 100644
--- a/mesonbuild/coredata.py
+++ b/mesonbuild/coredata.py
@@ -81,7 +81,7 @@ class UserOption(T.Generic[_T], HoldableObject):
         if not isinstance(yielding, bool):
             raise MesonException('Value of "yielding" must be a boolean.')
         self.yielding = yielding
-        self.deprecated: T.Union[bool, T.Dict[str, str], T.List[str]] = False
+        self.deprecated: T.Union[bool, str, T.Dict[str, str], T.List[str]] = False
 
     def listify(self, value: T.Any) -> T.List[T.Any]:
         return [value]
@@ -660,6 +660,19 @@ class CoreData:
                 return v
             newvalue = [replace(v) for v in opt.listify(value)]
             value = ','.join(newvalue)
+        elif isinstance(opt.deprecated, str):
+            # Option is deprecated and replaced by another. Note that a project
+            # option could be replaced by a built-in or module option, which is
+            # why we use OptionKey.from_string(newname) instead of
+            # key.evolve(newname). We set the value on both the old and new names,
+            # assuming they accept the same value. That could for example be
+            # achieved by adding the values from old option as deprecated on the
+            # new option, for example in the case of boolean option is replaced
+            # by a feature option with a different name.
+            newname = opt.deprecated
+            newkey = OptionKey.from_string(newname).evolve(subproject=key.subproject)
+            mlog.deprecation(f'Option {key.name!r} is replaced by {newname!r}')
+            self.set_option(newkey, value)
 
         opt.set_value(value)
 
diff --git a/mesonbuild/optinterpreter.py b/mesonbuild/optinterpreter.py
index eeb7cf8..549d564 100644
--- a/mesonbuild/optinterpreter.py
+++ b/mesonbuild/optinterpreter.py
@@ -32,7 +32,7 @@ if T.TYPE_CHECKING:
         'value': object,
         'min': T.Optional[int],
         'max': T.Optional[int],
-        'deprecated': T.Union[bool, T.Dict[str, str], T.List[str]],
+        'deprecated': T.Union[bool, str, T.Dict[str, str], T.List[str]],
         })
     ParserArgs = TypedDict('ParserArgs', {
         'yield': bool,
@@ -153,7 +153,7 @@ class OptionInterpreter:
                   KwargInfo('value', object),
                   KwargInfo('min', (int, type(None))),
                   KwargInfo('max', (int, type(None))),
-                  KwargInfo('deprecated', (bool, ContainerTypeInfo(dict, str), ContainerTypeInfo(list, str)),
+                  KwargInfo('deprecated', (bool, str, ContainerTypeInfo(dict, str), ContainerTypeInfo(list, str)),
                             default=False, since='0.60.0')
                   )
     @typed_pos_args('option', str)
@@ -177,7 +177,8 @@ class OptionInterpreter:
         parser_kwargs = {k: v for k, v in kwargs.items() if k in known_parser_kwargs and v is not None}
         opt = parser(description, T.cast('ParserArgs', parser_kwargs))
         opt.deprecated = kwargs['deprecated']
-
+        if isinstance(opt.deprecated, str):
+            FeatureNew.single_use('String value to "deprecated" keyword argument', '0.63.0', self.subproject)
         if key in self.options:
             mlog.deprecation(f'Option {opt_name} already exists.')
         self.options[key] = opt