Fix subprojects logic in cross build scenarios

Where we cannot use the same subproject state for both machines.

We may not even need to use a subproject for both machines, for example
if the build machine has a dependency installed, and we only need to
fall back to a subproject for the host machine.

Fixes: mesonbuild#10947

mesonbuild/build.py

@@ -291,12 +291,22 @@ def get_custom_targets(self):
 
     def copy(self) -> Build:
         other = Build(self.environment)
+        self._copy_to(other)
+        return other
+
+    def copy_to_native(self) -> Build:
+        other = Build(self.environment.copy_to_native())
+        self._copy_to(other)
+        return other
+
+    def _copy_to(self, other: Build) -> None:
         for k, v in self.__dict__.items():
+            if k == 'environment':
+                continue
             if isinstance(v, (list, dict, set, OrderedDict)):
                 other.__dict__[k] = v.copy()
             else:
                 other.__dict__[k] = v
-        return other
 
     def merge(self, other: Build) -> None:
         for k, v in other.__dict__.items():
@@ -307,7 +317,7 @@ def ensure_static_linker(self, compiler: Compiler) -> None:
             self.static_linker[compiler.for_machine] = detect_static_linker(self.environment, compiler)
 
     def get_project(self):
-        return self.projects['']
+        return self.projects[('', MachineChoice.HOST)]
 
     def get_subproject_dir(self):
         return self.subproject_dir
@@ -596,7 +606,7 @@ def get_basename(self) -> str:
         return self.name
 
     def get_subdir(self) -> str:
-        return self.subdir
+        return self.environment.build_output_rpath(self.subdir)
 
     def get_typename(self) -> str:
         return self.typename
@@ -612,7 +622,7 @@ def _get_id_hash(target_id: str) -> str:
         return h.hexdigest()[:7]
 
     @staticmethod
-    def construct_id_from_path(subdir: str, name: str, type_suffix: str) -> str:
+    def construct_id_from_path(subdir: str, name: str, type_suffix: str, extra_suffix: str = '') -> str:
         """Construct target ID from subdir, name and type suffix.
 
         This helper function is made public mostly for tests."""
@@ -623,7 +633,7 @@ def construct_id_from_path(subdir: str, name: str, type_suffix: str) -> str:
         # FIXME replace with assert when slash in names is prohibited
         name_part = name.replace('/', '@').replace('\\', '@')
         assert not has_path_sep(type_suffix)
-        my_id = name_part + type_suffix
+        my_id = name_part + type_suffix + extra_suffix
         if subdir:
             subdir_part = Target._get_id_hash(subdir)
             # preserve myid for better debuggability
@@ -635,7 +645,7 @@ def get_id(self) -> str:
         if getattr(self, 'name_suffix_set', False):
             name += '.' + self.suffix
         return self.construct_id_from_path(
-            self.subdir, name, self.type_suffix())
+            self.subdir, name, self.type_suffix(), '@native' if self.environment.is_native_clone else '')
 
     def process_kwargs_base(self, kwargs: T.Dict[str, T.Any]) -> None:
         if 'build_by_default' in kwargs:
@@ -1481,6 +1491,8 @@ def check_can_link_together(self, t: BuildTargetTypes) -> None:
         links_with_rust_abi = isinstance(t, BuildTarget) and t.uses_rust_abi()
         if not self.uses_rust() and links_with_rust_abi:
             raise InvalidArguments(f'Try to link Rust ABI library {t.name!r} with a non-Rust target {self.name!r}')
+        if t.subproject and not self.environment.is_cross_build():
+            return
         if self.for_machine is not t.for_machine and (not links_with_rust_abi or t.rust_crate_type != 'proc-macro'):
             msg = f'Tried to mix libraries for machines {self.for_machine} and {t.for_machine} in target {self.name!r}'
             if self.environment.is_cross_build():

mesonbuild/coredata.py

@@ -586,6 +586,30 @@ def __init__(self, options: argparse.Namespace, scratch_dir: str, meson_command:
         self.builtin_options_libdir_cross_fixup()
         self.init_builtins('')
 
+        self.is_native_clone = False
+
+    def copy_to_native(self) -> CoreData:
+        other = CoreData.__new__(CoreData)
+        for k, v in self.__dict__.items():
+            other.__dict__[k] = v
+
+        other.cross_files = []
+
+        other.compilers = PerMachine(OrderedDict(), OrderedDict())
+        other.compilers.build = self.compilers.build
+
+        other.deps = PerMachineDefaultable.default(
+            is_cross=False,
+            build=self.deps.build,
+            host=self.deps.host)
+
+        other.is_native_clone = True
+
+        other.compiler_check_cache.clear()
+        other.run_check_cache.clear()
+
+        return other
+
     @staticmethod
     def __load_config_files(options: argparse.Namespace, scratch_dir: str, ftype: str) -> T.List[str]:
         # Need to try and make the passed filenames absolute because when the
@@ -927,7 +951,9 @@ def copy_build_options_from_regular_ones(self) -> bool:
     def set_options(self, options: T.Dict[OptionKey, T.Any], subproject: str = '', first_invocation: bool = False) -> bool:
         dirty = False
         if not self.is_cross_build():
-            options = {k: v for k, v in options.items() if k.machine is not MachineChoice.BUILD}
+            other_machine = MachineChoice.HOST if self.is_native_clone else MachineChoice.BUILD
+            options = {k: v for k, v in options.items() if k.machine is not other_machine}
+
         # Set prefix first because it's needed to sanitize other options
         pfk = OptionKey('prefix')
         if pfk in options:
@@ -950,7 +976,7 @@ def set_options(self, options: T.Dict[OptionKey, T.Any], subproject: str = '', f
             sub = f'In subproject {subproject}: ' if subproject else ''
             raise MesonException(f'{sub}Unknown options: "{unknown_options_str}"')
 
-        if not self.is_cross_build():
+        if not self.is_cross_build() and not self.is_native_clone:
             dirty |= self.copy_build_options_from_regular_ones()
 
         return dirty

mesonbuild/environment.py

@@ -620,6 +620,37 @@ def __init__(self, source_dir: str, build_dir: str, options: 'argparse.Namespace
         self.default_pkgconfig = ['pkg-config']
         self.wrap_resolver: T.Optional['Resolver'] = None
 
+        self.is_native_clone = False
+
+    def copy_to_native(self) -> Environment:
+        other = Environment.__new__(Environment)
+        for k, v in self.__dict__.items():
+            other.__dict__[k] = v
+
+        other.coredata = self.coredata.copy_to_native()
+
+        machines: PerThreeMachineDefaultable[MachineInfo] = PerThreeMachineDefaultable()
+        machines.build = self.machines.build
+        other.machines = machines.default_missing()
+
+        binaries: PerMachineDefaultable[BinaryTable] = PerMachineDefaultable()
+        binaries.build = self.binaries.build
+        other.binaries = binaries.default_missing()
+
+        properties: PerMachineDefaultable[Properties] = PerMachineDefaultable()
+        properties.build = self.properties.build
+        other.properties = properties.default_missing()
+
+        cmakevars: PerMachineDefaultable[CMakeVariables] = PerMachineDefaultable()
+        cmakevars.build = self.cmakevars.build
+        other.cmakevars = cmakevars.default_missing()
+
+        other.exe_wrapper = None
+
+        other.is_native_clone = True
+
+        return other
+
     def _load_machine_file_options(self, config: 'ConfigParser', properties: Properties, machine: MachineChoice) -> None:
         """Read the contents of a Machine file and put it in the options store."""
 
@@ -841,6 +872,12 @@ def get_source_dir(self) -> str:
     def get_build_dir(self) -> str:
         return self.build_dir
 
+    def build_output_rpath(self, subdir: str, *parts: T.Sequence[str]) -> str:
+        result = subdir
+        if self.is_native_clone:
+            result += '-native'
+        return os.path.join(result, *parts)
+
     def get_import_lib_dir(self) -> str:
         "Install dir for the import library (library used for linking)"
         return self.get_libdir()

mesonbuild/interpreter/dependencyfallbacks.py

@@ -74,7 +74,7 @@ def _do_dependency_cache(self, kwargs: TYPE_nkwargs, func_args: TYPE_nvar, func_
         name = func_args[0]
         cached_dep = self._get_cached_dep(name, kwargs)
         if cached_dep:
-            self._verify_fallback_consistency(cached_dep)
+            self._verify_fallback_consistency(cached_dep, kwargs.get('native', False))
         return cached_dep
 
     def _do_dependency(self, kwargs: TYPE_nkwargs, func_args: TYPE_nvar, func_kwargs: TYPE_nkwargs) -> T.Optional[Dependency]:
@@ -95,7 +95,7 @@ def _do_dependency(self, kwargs: TYPE_nkwargs, func_args: TYPE_nvar, func_kwargs
     def _do_existing_subproject(self, kwargs: TYPE_nkwargs, func_args: TYPE_nvar, func_kwargs: TYPE_nkwargs) -> T.Optional[Dependency]:
         subp_name = func_args[0]
         varname = self.subproject_varname
-        if subp_name and self._get_subproject(subp_name):
+        if subp_name and self._get_subproject(subp_name, kwargs.get('native', False)):
             return self._get_subproject_dep(subp_name, varname, kwargs)
         return None
 
@@ -127,18 +127,21 @@ def _do_subproject(self, kwargs: TYPE_nkwargs, func_args: TYPE_nvar, func_kwargs
         func_kwargs.setdefault('version', [])
         if 'default_options' in kwargs and isinstance(kwargs['default_options'], str):
             func_kwargs['default_options'] = listify(kwargs['default_options'])
+        func_kwargs.setdefault('native', kwargs.get('native', False))
         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]:
-        sub = self.interpreter.subprojects.get(subp_name)
+    def _get_subproject(self, subp_name: str, native: bool) -> T.Optional[SubprojectHolder]:
+        sub = self.interpreter.find_subproject(subp_name, native)
         if sub and sub.found():
             return sub
         return None
 
     def _get_subproject_dep(self, subp_name: str, varname: str, kwargs: TYPE_nkwargs) -> T.Optional[Dependency]:
+        native = kwargs.get('native', False)
+
         # Verify the subproject is found
-        subproject = self._get_subproject(subp_name)
+        subproject = self._get_subproject(subp_name, native)
         if not subproject:
             mlog.log('Dependency', mlog.bold(self._display_name), 'from subproject',
                      mlog.bold(subp_name), 'found:', mlog.red('NO'),
@@ -160,7 +163,7 @@ def _get_subproject_dep(self, subp_name: str, varname: str, kwargs: TYPE_nkwargs
         # If we have cached_dep we did all the checks and logging already in
         # self._get_cached_dep().
         if cached_dep:
-            self._verify_fallback_consistency(cached_dep)
+            self._verify_fallback_consistency(cached_dep, native)
             return cached_dep
 
         # Legacy: Use the variable name if provided instead of relying on the
@@ -256,10 +259,12 @@ def _get_subproject_variable(self, subproject: SubprojectHolder, varname: str) -
             return None
         return var_dep
 
-    def _verify_fallback_consistency(self, cached_dep: Dependency) -> None:
+    def _verify_fallback_consistency(self, cached_dep: Dependency, native: bool) -> None:
         subp_name = self.subproject_name
+        if subp_name is None:
+            return
         varname = self.subproject_varname
-        subproject = self._get_subproject(subp_name)
+        subproject = self._get_subproject(subp_name, native)
         if subproject and varname:
             var_dep = self._get_subproject_variable(subproject, varname)
             if var_dep and cached_dep.found() and var_dep != cached_dep:
@@ -336,7 +341,8 @@ def lookup(self, kwargs: TYPE_nkwargs, force_fallback: bool = False) -> Dependen
                 subp_name, varname = self.wrap_resolver.find_dep_provider(name)
                 if subp_name:
                     self.forcefallback |= subp_name in force_fallback_for
-                    if self.forcefallback or self.allow_fallback is True or required or self._get_subproject(subp_name):
+                    if self.forcefallback or self.allow_fallback is True or required \
+                            or self._get_subproject(subp_name, kwargs.get('native', False)):
                         self._subproject_impl(subp_name, varname)
                     break