Allow to fallback to cmake subproject

The method can be overridden by setting the `method` key in the wrap
file and always defaults to 'meson'. cmake.subproject() is still needed
in case specific cmake options need to be passed.

This also makes it easier to extend to other methods in the future e.g.
cargo.

2 files changed, 7 insertions, 9 deletions

diff --git a/mesonbuild/interpreter/dependencyfallbacks.py b/mesonbuild/interpreter/dependencyfallbacks.py
index 7ef1527..eca6a2c 100644
--- a/mesonbuild/interpreter/dependencyfallbacks.py
+++ b/mesonbuild/interpreter/dependencyfallbacks.py
@@ -127,7 +127,7 @@ class DependencyFallbacksHolder(MesonInterpreterObject):
         func_kwargs.setdefault('version', [])
         if 'default_options' in kwargs and isinstance(kwargs['default_options'], str):
             func_kwargs['default_options'] = listify(kwargs['default_options'])
-        self.interpreter.do_subproject(subp_name, 'meson', func_kwargs)
+        self.interpreter.do_subproject(subp_name, func_kwargs)
         return self._get_subproject_dep(subp_name, varname, kwargs)
 
     def _get_subproject(self, subp_name: str) -> T.Optional[SubprojectHolder]:
diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index a5c8a5a..e0c17e6 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -116,8 +116,6 @@ import copy
 if T.TYPE_CHECKING:
     import argparse
 
-    from typing_extensions import Literal
-
     from . import kwargs as kwtypes
     from ..backend.backends import Backend
     from ..interpreterbase.baseobjects import InterpreterObject, TYPE_var, TYPE_kwargs
@@ -868,7 +866,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             'options': None,
             'cmake_options': [],
         }
-        return self.do_subproject(args[0], 'meson', kw)
+        return self.do_subproject(args[0], kw)
 
     def disabled_subproject(self, subp_name: str, disabled_feature: T.Optional[str] = None,
                             exception: T.Optional[Exception] = None) -> SubprojectHolder:
@@ -877,7 +875,7 @@ class Interpreter(InterpreterBase, HoldableObject):
         self.subprojects[subp_name] = sub
         return sub
 
-    def do_subproject(self, subp_name: str, method: Literal['meson', 'cmake'], kwargs: kwtypes.DoSubproject) -> SubprojectHolder:
+    def do_subproject(self, subp_name: str, kwargs: kwtypes.DoSubproject, force_method: T.Optional[wrap.Method] = None) -> SubprojectHolder:
         disabled, required, feature = extract_required_kwarg(kwargs, self.subproject)
         if disabled:
             mlog.log('Subproject', mlog.bold(subp_name), ':', 'skipped: feature', mlog.bold(feature), 'disabled')
@@ -913,7 +911,7 @@ class Interpreter(InterpreterBase, HoldableObject):
 
         r = self.environment.wrap_resolver
         try:
-            subdir = r.resolve(subp_name, method)
+            subdir, method = r.resolve(subp_name, force_method)
         except wrap.WrapException as e:
             if not required:
                 mlog.log(e)
@@ -1009,8 +1007,8 @@ class Interpreter(InterpreterBase, HoldableObject):
             prefix = self.coredata.options[OptionKey('prefix')].value
 
             from ..modules.cmake import CMakeSubprojectOptions
-            options = kwargs['options'] or CMakeSubprojectOptions()
-            cmake_options = kwargs['cmake_options'] + options.cmake_options
+            options = kwargs.get('options') or CMakeSubprojectOptions()
+            cmake_options = kwargs.get('cmake_options', []) + options.cmake_options
             cm_int = CMakeInterpreter(new_build, Path(subdir), Path(subdir_abs), Path(prefix), new_build.environment, self.backend)
             cm_int.initialise(cmake_options)
             cm_int.analyse()
@@ -1734,7 +1732,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             'cmake_options': [],
             'options': None,
         }
-        self.do_subproject(fallback, 'meson', sp_kwargs)
+        self.do_subproject(fallback, sp_kwargs)
         return self.program_from_overrides(args, extra_info)
 
     @typed_pos_args('find_program', varargs=(str, mesonlib.File), min_varargs=1)