environment: make fully type safe

This as much as anything is to stop lying to envconfig about the
potential types it will be given.

mesonbuild/compilers/compilers.py

@@ -1381,6 +1381,8 @@ def get_global_options(lang: str,
 
     comp_options = env.options.get(comp_key, [])
     link_options = env.options.get(largkey, [])
+    assert isinstance(comp_options, (str, list)), 'for mypy'
+    assert isinstance(link_options, (str, list)), 'for mypy'
 
     cargs = options.UserStringArrayOption(
         f'{lang}_{argkey.name}',

mesonbuild/envconfig.py

@@ -13,6 +13,9 @@
 from . import mlog
 from pathlib import Path
 
+if T.TYPE_CHECKING:
+    from .options import ElementaryOptionValues
+
 
 # These classes contains all the data pulled from configuration files (native
 # and cross file currently), and also assists with the reading environment
@@ -153,7 +156,7 @@ class CMakeSkipCompilerTest(Enum):
 class Properties:
     def __init__(
             self,
-            properties: T.Optional[T.Dict[str, T.Optional[T.Union[str, bool, int, T.List[str]]]]] = None,
+            properties: T.Optional[T.Dict[str, ElementaryOptionValues]] = None,
     ):
         self.properties = properties or {}
 
@@ -270,7 +273,9 @@ def __repr__(self) -> str:
         return f'<MachineInfo: {self.system} {self.cpu_family} ({self.cpu})>'
 
     @classmethod
-    def from_literal(cls, literal: T.Dict[str, str]) -> 'MachineInfo':
+    def from_literal(cls, raw: T.Dict[str, ElementaryOptionValues]) -> 'MachineInfo':
+        assert all(isinstance(v, str) for v in raw.values()), 'for mypy'
+        literal = T.cast('T.Dict[str, str]', raw)
         minimum_literal = {'cpu', 'cpu_family', 'endian', 'system'}
         if set(literal) < minimum_literal:
             raise EnvironmentException(
@@ -389,7 +394,7 @@ class BinaryTable:
 
     def __init__(
             self,
-            binaries: T.Optional[T.Dict[str, T.Union[str, T.List[str]]]] = None,
+            binaries: T.Optional[T.Mapping[str, ElementaryOptionValues]] = None,
     ):
         self.binaries: T.Dict[str, T.List[str]] = {}
         if binaries:

mesonbuild/environment.py

@@ -41,10 +41,9 @@
 from mesonbuild import envconfig
 
 if T.TYPE_CHECKING:
-    from configparser import ConfigParser
-
     from .compilers import Compiler
     from .compilers.mixins.visualstudio import VisualStudioLikeCompiler
+    from .options import ElementaryOptionValues
     from .wrap.wrap import Resolver
     from . import cargo
 
@@ -633,7 +632,7 @@ def __init__(self, source_dir: str, build_dir: str, cmd_options: coredata.Shared
         #
         # Note that order matters because of 'buildtype', if it is after
         # 'optimization' and 'debug' keys, it override them.
-        self.options: T.MutableMapping[OptionKey, T.Union[str, T.List[str]]] = collections.OrderedDict()
+        self.options: T.MutableMapping[OptionKey, ElementaryOptionValues] = collections.OrderedDict()
 
         ## Read in native file(s) to override build machine configuration
 
@@ -702,7 +701,8 @@ def __init__(self, source_dir: str, build_dir: str, cmd_options: coredata.Shared
         # Store a global state of Cargo dependencies
         self.cargo: T.Optional[cargo.Interpreter] = None
 
-    def _load_machine_file_options(self, config: 'ConfigParser', properties: Properties, machine: MachineChoice) -> None:
+    def _load_machine_file_options(self, config: T.Mapping[str, T.Mapping[str, ElementaryOptionValues]],
+                                   properties: Properties, machine: MachineChoice) -> None:
         """Read the contents of a Machine file and put it in the options store."""
 
         # Look for any options in the deprecated paths section, warn about
@@ -712,6 +712,7 @@ def _load_machine_file_options(self, config: 'ConfigParser', properties: Propert
         if paths:
             mlog.deprecation('The [paths] section is deprecated, use the [built-in options] section instead.')
             for k, v in paths.items():
+                assert isinstance(v, (str, list)), 'for mypy'
                 self.options[OptionKey.from_string(k).evolve(machine=machine)] = v
 
         # Next look for compiler options in the "properties" section, this is
@@ -724,6 +725,7 @@ def _load_machine_file_options(self, config: 'ConfigParser', properties: Propert
         for k, v in properties.properties.copy().items():
             if k in deprecated_properties:
                 mlog.deprecation(f'{k} in the [properties] section of the machine file is deprecated, use the [built-in options] section.')
+                assert isinstance(v, (str, list)), 'for mypy'
                 self.options[OptionKey.from_string(k).evolve(machine=machine)] = v
                 del properties.properties[k]
 

run_mypy.py

@@ -36,6 +36,7 @@
     # 'mesonbuild/coredata.py',
     'mesonbuild/depfile.py',
     'mesonbuild/envconfig.py',
+    'mesonbuild/environment.py',
     'mesonbuild/interpreter/compiler.py',
     'mesonbuild/interpreter/mesonmain.py',
     'mesonbuild/interpreter/interpreterobjects.py',