holders: Introduce HoldableObject

12 files changed, 78 insertions, 42 deletions

diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 8724cab7..a9abcf9 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -28,6 +28,7 @@ from . import dependencies
 from . import mlog
 from . import programs
 from .mesonlib import (
+    HoldableObject,
     File, MesonException, MachineChoice, PerMachine, OrderedSet, listify,
     extract_as_list, typeslistify, stringlistify, classify_unity_sources,
     get_filenames_templates_dict, substitute_values, has_path_sep, unholder,
@@ -125,13 +126,13 @@ def get_target_macos_dylib_install_name(ld) -> str:
 class InvalidArguments(MesonException):
     pass
 
-class DependencyOverride:
+class DependencyOverride(HoldableObject):
     def __init__(self, dep, node, explicit=True):
         self.dep = dep
         self.node = node
         self.explicit = explicit
 
-class Headers:
+class Headers(HoldableObject):
 
     def __init__(self, sources: T.List[File], install_subdir: T.Optional[str],
                  install_dir: T.Optional[str], install_mode: T.Optional['FileMode'],
@@ -161,7 +162,7 @@ class Headers:
         return self.custom_install_mode
 
 
-class Man:
+class Man(HoldableObject):
 
     def __init__(self, sources: T.List[File], install_dir: T.Optional[str],
                  install_mode: T.Optional['FileMode'], subproject: str,
@@ -182,7 +183,7 @@ class Man:
         return self.sources
 
 
-class InstallDir:
+class InstallDir(HoldableObject):
 
     def __init__(self, src_subdir: str, inst_subdir: str, install_dir: str,
                  install_mode: T.Optional['FileMode'],
@@ -327,12 +328,11 @@ class Build:
 
         return link_args.get(compiler.get_language(), [])
 
-class IncludeDirs:
+class IncludeDirs(HoldableObject):
 
     """Internal representation of an include_directories call."""
 
-    def __init__(self, curdir: str, dirs: T.List[str], is_system: bool,
-                 extra_build_dirs: T.Optional[T.List[str]] = None):
+    def __init__(self, curdir: str, dirs: T.List[str], is_system: bool, extra_build_dirs: T.Optional[T.List[str]] = None):
         self.curdir = curdir
         self.incdirs = dirs
         self.is_system = is_system
@@ -361,7 +361,7 @@ class IncludeDirs:
             strlist.append(os.path.join(sourcedir, self.curdir, idir))
         return strlist
 
-class ExtractedObjects:
+class ExtractedObjects(HoldableObject):
     '''
     Holds a list of sources for which the objects must be extracted
     '''
@@ -416,7 +416,7 @@ class ExtractedObjects:
             for source in self.srclist
         ]
 
-class EnvironmentVariables:
+class EnvironmentVariables(HoldableObject):
     def __init__(self) -> None:
         self.envvars = []
         # The set of all env vars we have operations for. Only used for self.has_name()
@@ -458,7 +458,7 @@ class EnvironmentVariables:
             env[name] = method(env, name, values, separator)
         return env
 
-class Target:
+class Target(HoldableObject):
 
     # TODO: should Target be an abc.ABCMeta?
 
@@ -1508,7 +1508,7 @@ You probably should put it in link_with instead.''')
                                  'platforms')
                 return
 
-class Generator:
+class Generator(HoldableObject):
     def __init__(self, exe: T.Union['Executable', programs.ExternalProgram],
                  arguments: T.List[str],
                  output: T.List[str],
@@ -1584,7 +1584,7 @@ class Generator:
         return output
 
 
-class GeneratedList:
+class GeneratedList(HoldableObject):
 
     """The output of generator.process."""
 
@@ -2527,7 +2527,7 @@ class Jar(BuildTarget):
             return ['-cp', os.pathsep.join(cp_paths)]
         return []
 
-class CustomTargetIndex:
+class CustomTargetIndex(HoldableObject):
 
     """A special opaque object returned by indexing a CustomTarget. This object
     exists in Meson, but acts as a proxy in the backends, making targets depend
@@ -2583,7 +2583,7 @@ class CustomTargetIndex:
     def get_custom_install_dir(self):
         return self.target.get_custom_install_dir()
 
-class ConfigurationData:
+class ConfigurationData(HoldableObject):
     def __init__(self) -> None:
         super().__init__()
         self.values = {}  # T.Dict[str, T.Union[str, int, bool]]
@@ -2602,7 +2602,7 @@ class ConfigurationData:
 
 # A bit poorly named, but this represents plain data files to copy
 # during install.
-class Data:
+class Data(HoldableObject):
     def __init__(self, sources: T.List[File], install_dir: str,
                  install_mode: T.Optional['FileMode'], subproject: str,
                  rename: T.List[str] = None):
diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index 19288eb..efe521c 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -23,6 +23,7 @@ from .. import coredata
 from .. import mlog
 from .. import mesonlib
 from ..mesonlib import (
+    HoldableObject,
     EnvironmentException, MachineChoice, MesonException,
     Popen_safe, LibType, TemporaryDirectoryWinProof, OptionKey,
 )
@@ -435,7 +436,7 @@ def get_base_link_args(options: 'KeyedOptionDictType', linker: 'Compiler',
 class CrossNoRunException(MesonException):
     pass
 
-class RunResult:
+class RunResult(HoldableObject):
     def __init__(self, compiled: bool, returncode: int = 999,
                  stdout: str = 'UNDEFINED', stderr: str = 'UNDEFINED'):
         self.compiled = compiled
@@ -444,7 +445,7 @@ class RunResult:
         self.stderr = stderr
 
 
-class CompileResult:
+class CompileResult(HoldableObject):
 
     """The result of Compiler.compiles (and friends)."""
 
@@ -467,7 +468,7 @@ class CompileResult:
         self.text_mode = text_mode
 
 
-class Compiler(metaclass=abc.ABCMeta):
+class Compiler(HoldableObject, metaclass=abc.ABCMeta):
     # Libraries to ignore in find_library() since they are provided by the
     # compiler or the C library. Currently only used for MSVC.
     ignore_libs = []  # type: T.List[str]
diff --git a/mesonbuild/coredata.py b/mesonbuild/coredata.py
index 89cec46..107e4b8 100644
--- a/mesonbuild/coredata.py
+++ b/mesonbuild/coredata.py
@@ -19,6 +19,7 @@ from itertools import chain
 from pathlib import PurePath
 from collections import OrderedDict
 from .mesonlib import (
+    HoldableObject,
     MesonException, EnvironmentException, MachineChoice, PerMachine,
     PerMachineDefaultable, default_libdir, default_libexecdir,
     default_prefix, split_args, OptionKey, OptionType, stringlistify,
@@ -61,7 +62,7 @@ class MesonVersionMismatchException(MesonException):
         self.current_version = current_version
 
 
-class UserOption(T.Generic[_T]):
+class UserOption(T.Generic[_T], HoldableObject):
     def __init__(self, description: str, choices: T.Optional[T.Union[str, T.List[_T]]], yielding: T.Optional[bool]):
         super().__init__()
         self.choices = choices
@@ -255,6 +256,7 @@ class UserFeatureOption(UserComboOption):
 
     def __init__(self, description: str, value: T.Any, yielding: T.Optional[bool] = None):
         super().__init__(description, self.static_choices, value, yielding)
+        self.name: T.Optional[str] = None  # TODO: Refactor options to all store their name
 
     def is_enabled(self) -> bool:
         return self.value == 'enabled'
diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index 515edcf..e12c697 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -22,7 +22,7 @@ from enum import Enum
 
 from .. import mlog
 from ..compilers import clib_langs
-from ..mesonlib import MachineChoice, MesonException
+from ..mesonlib import MachineChoice, MesonException, HoldableObject
 from ..mesonlib import version_compare_many
 from ..interpreterbase import FeatureDeprecated
 
@@ -65,7 +65,7 @@ class DependencyMethods(Enum):
 DependencyTypeName = T.NewType('DependencyTypeName', str)
 
 
-class Dependency:
+class Dependency(HoldableObject):
 
     @classmethod
     def _process_include_type_kw(cls, kwargs: T.Dict[str, T.Any]) -> str:
diff --git a/mesonbuild/envconfig.py b/mesonbuild/envconfig.py
index a93905a..307aac3 100644
--- a/mesonbuild/envconfig.py
+++ b/mesonbuild/envconfig.py
@@ -17,7 +17,7 @@ import typing as T
 from enum import Enum
 
 from . import mesonlib
-from .mesonlib import EnvironmentException
+from .mesonlib import EnvironmentException, HoldableObject
 from . import mlog
 from pathlib import Path
 
@@ -232,7 +232,7 @@ class Properties:
     def get(self, key: str, default: T.Optional[T.Union[str, bool, int, T.List[str]]] = None) -> T.Optional[T.Union[str, bool, int, T.List[str]]]:
         return self.properties.get(key, default)
 
-class MachineInfo:
+class MachineInfo(HoldableObject):
     def __init__(self, system: str, cpu_family: str, cpu: str, endian: str):
         self.system = system
         self.cpu_family = cpu_family
diff --git a/mesonbuild/interpreter/__init__.py b/mesonbuild/interpreter/__init__.py
index 58ee729..62b09bf 100644
--- a/mesonbuild/interpreter/__init__.py
+++ b/mesonbuild/interpreter/__init__.py
@@ -20,6 +20,6 @@ from .interpreter import Interpreter, permitted_dependency_kwargs
 from .compiler import CompilerHolder
 from .interpreterobjects import (ExecutableHolder, BuildTargetHolder, CustomTargetHolder,
                                  CustomTargetIndexHolder, MachineHolder, Test,
-                                 ConfigurationDataHolder, SubprojectHolder, DependencyHolder,
+                                 ConfigurationDataObject, SubprojectHolder, DependencyHolder,
                                  GeneratedListHolder, ExternalProgramHolder,
                                  extract_required_kwarg)
diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index b4cdb57..ea36288 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -230,7 +230,7 @@ permitted_dependency_kwargs = {
     'version',
 }
 
-class Interpreter(InterpreterBase):
+class Interpreter(InterpreterBase, HoldableObject):
 
     def __init__(
                 self,
diff --git a/mesonbuild/interpreter/interpreterobjects.py b/mesonbuild/interpreter/interpreterobjects.py
index e27c1f7..db42c67 100644
--- a/mesonbuild/interpreter/interpreterobjects.py
+++ b/mesonbuild/interpreter/interpreterobjects.py
@@ -24,7 +24,7 @@ from ..interpreterbase import (ContainerTypeInfo, KwargInfo,
 from ..interpreterbase.decorators import FeatureCheckBase
 from ..dependencies import Dependency, ExternalLibrary, InternalDependency
 from ..programs import ExternalProgram
-from ..mesonlib import FileMode, OptionKey, listify, Popen_safe
+from ..mesonlib import HoldableObject, MesonException, OptionKey, listify, Popen_safe
 
 import typing as T
 
diff --git a/mesonbuild/interpreterbase/baseobjects.py b/mesonbuild/interpreterbase/baseobjects.py
index b08da2f..d910e51 100644
--- a/mesonbuild/interpreterbase/baseobjects.py
+++ b/mesonbuild/interpreterbase/baseobjects.py
@@ -15,24 +15,33 @@
 from .. import mparser
 from .exceptions import InvalidCode
 from .helpers import flatten
+from ..mesonlib import HoldableObject
 
 import typing as T
 
+if T.TYPE_CHECKING:
+    # Object holders need the actual interpreter
+    from ..interpreter import Interpreter
+
 TV_fw_var = T.Union[str, int, bool, list, dict, 'InterpreterObject']
 TV_fw_args = T.List[T.Union[mparser.BaseNode, TV_fw_var]]
 TV_fw_kwargs = T.Dict[str, T.Union[mparser.BaseNode, TV_fw_var]]
 
 TV_func = T.TypeVar('TV_func', bound=T.Callable[..., T.Any])
 
-TYPE_elementary = T.Union[str, int, bool]
-TYPE_var = T.Union[TYPE_elementary, T.List[T.Any], T.Dict[str, T.Any], 'InterpreterObject']
+TYPE_elementary = T.Union[str, int, bool, T.List[T.Any], T.Dict[str, T.Any]]
+TYPE_var = T.Union[TYPE_elementary, HoldableObject, 'MesonInterpreterObject']
 TYPE_nvar = T.Union[TYPE_var, mparser.BaseNode]
+TYPE_kwargs = T.Dict[str, TYPE_var]
 TYPE_nkwargs = T.Dict[str, TYPE_nvar]
 TYPE_key_resolver = T.Callable[[mparser.BaseNode], str]
 
 class InterpreterObject:
     def __init__(self, *, subproject: T.Optional[str] = None) -> None:
-        self.methods = {}  # type: T.Dict[str, T.Callable[[T.List[TYPE_nvar], TYPE_nkwargs], TYPE_var]]
+        self.methods: T.Dict[
+            str,
+            T.Callable[[T.List[TYPE_var], TYPE_kwargs], TYPE_var]
+        ] = {}
         # Current node set during a method call. This can be used as location
         # when printing a warning message during a method call.
         self.current_node:  mparser.BaseNode = None
@@ -41,8 +50,8 @@ class InterpreterObject:
     def method_call(
                 self,
                 method_name: str,
-                args: TV_fw_args,
-                kwargs: TV_fw_kwargs
+                args: T.List[TYPE_var],
+                kwargs: TYPE_kwargs
             ) -> TYPE_var:
         if method_name in self.methods:
             method = self.methods[method_name]
@@ -52,20 +61,23 @@ class InterpreterObject:
         raise InvalidCode('Unknown method "%s" in object.' % method_name)
 
 class MesonInterpreterObject(InterpreterObject):
-    ''' All non-elementary objects should be derived from this '''
+    ''' All non-elementary objects and non-object-holders should be derived from this '''
 
 class MutableInterpreterObject:
     ''' Dummy class to mark the object type as mutable '''
 
-TV_InterpreterObject = T.TypeVar('TV_InterpreterObject')
+InterpreterObjectTypeVar = T.TypeVar('InterpreterObjectTypeVar', bound=HoldableObject)
 
-class ObjectHolder(MesonInterpreterObject, T.Generic[TV_InterpreterObject]):
-    def __init__(self, obj: TV_InterpreterObject, *, subproject: T.Optional[str] = None) -> None:
-        super().__init__(subproject=subproject)
+class ObjectHolder(InterpreterObject, T.Generic[InterpreterObjectTypeVar]):
+    def __init__(self, obj: InterpreterObjectTypeVar, interpreter: 'Interpreter') -> None:
+        super().__init__(subproject=interpreter.subproject)
+        assert isinstance(obj, HoldableObject), f'This is a bug: Trying to hold object of type `{type(obj).__name__}` that is not an `HoldableObject`'
         self.held_object = obj
+        self.interpreter = interpreter
+        self.env = self.interpreter.environment
 
     def __repr__(self) -> str:
-        return f'<Holder: {self.held_object!r}>'
+        return f'<[{type(self).__name__}] holds [{type(self.held_object).__name__}]: {self.held_object!r}>'
 
 class RangeHolder(MesonInterpreterObject):
     def __init__(self, start: int, stop: int, step: int, *, subproject: T.Optional[str] = None) -> None:
diff --git a/mesonbuild/mesonlib/universal.py b/mesonbuild/mesonlib/universal.py
index 9daabee..8dc16dc 100644
--- a/mesonbuild/mesonlib/universal.py
+++ b/mesonbuild/mesonlib/universal.py
@@ -18,6 +18,7 @@ import enum
 import sys
 import stat
 import time
+import abc
 import platform, subprocess, operator, os, shlex, shutil, re
 import collections
 from functools import lru_cache, wraps, total_ordering
@@ -46,6 +47,7 @@ __all__ = [
     'an_unpicklable_object',
     'python_command',
     'project_meson_versions',
+    'HoldableObject',
     'File',
     'FileMode',
     'GitException',
@@ -267,6 +269,10 @@ def check_direntry_issues(direntry_array: T.Union[T.List[T.Union[str, bytes]], s
 import threading
 an_unpicklable_object = threading.Lock()
 
+class HoldableObject(metaclass=abc.ABCMeta):
+    ''' Dummy base class for all objects that can be
+        held by an interpreter.baseobjects.ObjectHolder '''
+
 class FileMode:
     # The first triad is for owner permissions, the second for group permissions,
     # and the third for others (everyone else).
@@ -366,7 +372,7 @@ dot_C_dot_H_warning = """You are using .C or .H files in your project. This is d
          Visual Studio compiler, as it treats .C files as C code, unless you add
          the /TP compiler flag, but this is unreliable.
          See https://github.com/mesonbuild/meson/pull/8747 for the discussions."""
-class File:
+class File(HoldableObject):
     def __init__(self, is_built: bool, subdir: str, fname: str):
         if fname.endswith(".C") or fname.endswith(".H"):
             mlog.warning(dot_C_dot_H_warning, once=True)
diff --git a/mesonbuild/programs.py b/mesonbuild/programs.py
index 1d93b8a..06af320 100644
--- a/mesonbuild/programs.py
+++ b/mesonbuild/programs.py
@@ -30,7 +30,7 @@ if T.TYPE_CHECKING:
     from .environment import Environment
 
 
-class ExternalProgram:
+class ExternalProgram(mesonlib.HoldableObject):
 
     """A program that is found on the system."""
 
diff --git a/run_unittests.py b/run_unittests.py
index f81462f..067404f 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -727,7 +727,15 @@ class InternalTests(unittest.TestCase):
         self.assertEqual([1, 2, 3], listify([1, [2, [3]]]))
         self.assertEqual([1, [2, [3]]], listify([1, [2, [3]]], flatten=False))
         # Test flattening and unholdering
-        holder1 = ObjectHolder(1)
+        class TestHeldObj(mesonbuild.mesonlib.HoldableObject):
+            def __init__(self, val: int) -> None:
+                self._val = val
+        class MockInterpreter:
+            def __init__(self) -> None:
+                self.subproject = ''
+                self.environment = None
+        heldObj1 = TestHeldObj(1)
+        holder1 = ObjectHolder(heldObj1, MockInterpreter())
         self.assertEqual([holder1], listify(holder1))
         self.assertEqual([holder1], listify([holder1]))
         self.assertEqual([holder1, 2], listify([holder1, 2]))
@@ -753,8 +761,16 @@ class InternalTests(unittest.TestCase):
         self.assertEqual([1, 2, 3], extract(kwargs, 'sources', pop=True))
         self.assertEqual(kwargs, {})
 
+        class TestHeldObj(mesonbuild.mesonlib.HoldableObject):
+            pass
+        class MockInterpreter:
+            def __init__(self) -> None:
+                self.subproject = ''
+                self.environment = None
+        heldObj = TestHeldObj()
+
         # Test unholding
-        holder3 = ObjectHolder(3)
+        holder3 = ObjectHolder(heldObj, MockInterpreter())
         kwargs = {'sources': [1, 2, holder3]}
         self.assertEqual(kwargs, {'sources': [1, 2, holder3]})
 
@@ -769,7 +785,6 @@ class InternalTests(unittest.TestCase):
         _mock.pcdep = mock.Mock()
         _mock.pcdep.name = "some_name"
         _mock.version_reqs = []
-        _mock = mock.Mock(held_object=_mock)
 
         # pkgconfig dependency as lib
         deps = mesonbuild.modules.pkgconfig.DependenciesHelper(dummystate, "thislib")