environment: fix minor typing issues

These include things like not narrowing unions and boolean error
handling

Author: dcbaker

mesonbuild/environment.py

@@ -44,6 +44,7 @@
     from configparser import ConfigParser
 
     from .compilers import Compiler
+    from .compilers.mixins.visualstudio import VisualStudioLikeCompiler
     from .wrap.wrap import Resolver
     from . import cargo
 
@@ -53,6 +54,11 @@
 build_filename = 'meson.build'
 
 
+def _as_str(val: object) -> str:
+    assert isinstance(val, str), 'for mypy'
+    return val
+
+
 def _get_env_var(for_machine: MachineChoice, is_cross: bool, var_name: str) -> T.Optional[str]:
     """
     Returns the exact env var and the value.
@@ -338,6 +344,7 @@ def detect_windows_arch(compilers: CompilersDict) -> str:
     # 32-bit and pretend like we're running under WOW64. Else, return the
     # actual Windows architecture that we deduced above.
     for compiler in compilers.values():
+        compiler = T.cast('VisualStudioLikeCompiler', compiler)
         if compiler.id == 'msvc' and (compiler.target in {'x86', '80x86'}):
             return 'x86'
         if compiler.id == 'clang-cl' and (compiler.target in {'x86', 'i686'}):
@@ -869,7 +876,12 @@ def create_new_coredata(self, options: coredata.SharedCMDOptions) -> None:
         # re-initialized with project options by the interpreter during
         # build file parsing.
         # meson_command is used by the regenchecker script, which runs meson
-        self.coredata = coredata.CoreData(options, self.scratch_dir, mesonlib.get_meson_command())
+        meson_command = mesonlib.get_meson_command()
+        if meson_command is None:
+            meson_command = []
+        else:
+            meson_command = meson_command.copy()
+        self.coredata = coredata.CoreData(options, self.scratch_dir, meson_command)
         self.first_invocation = True
 
     def is_cross_build(self, when_building_for: MachineChoice = MachineChoice.HOST) -> bool:
@@ -950,25 +962,25 @@ def get_static_lib_dir(self) -> str:
         return self.get_libdir()
 
     def get_prefix(self) -> str:
-        return self.coredata.get_option(OptionKey('prefix'))
+        return _as_str(self.coredata.get_option(OptionKey('prefix')))
 
     def get_libdir(self) -> str:
-        return self.coredata.get_option(OptionKey('libdir'))
+        return _as_str(self.coredata.get_option(OptionKey('libdir')))
 
     def get_libexecdir(self) -> str:
-        return self.coredata.get_option(OptionKey('libexecdir'))
+        return _as_str(self.coredata.get_option(OptionKey('libexecdir')))
 
     def get_bindir(self) -> str:
-        return self.coredata.get_option(OptionKey('bindir'))
+        return _as_str(self.coredata.get_option(OptionKey('bindir')))
 
     def get_includedir(self) -> str:
-        return self.coredata.get_option(OptionKey('includedir'))
+        return _as_str(self.coredata.get_option(OptionKey('includedir')))
 
     def get_mandir(self) -> str:
-        return self.coredata.get_option(OptionKey('mandir'))
+        return _as_str(self.coredata.get_option(OptionKey('mandir')))
 
     def get_datadir(self) -> str:
-        return self.coredata.get_option(OptionKey('datadir'))
+        return _as_str(self.coredata.get_option(OptionKey('datadir')))
 
     def get_compiler_system_lib_dirs(self, for_machine: MachineChoice) -> T.List[str]:
         for comp in self.coredata.compilers[for_machine].values():
@@ -986,8 +998,8 @@ def get_compiler_system_lib_dirs(self, for_machine: MachineChoice) -> T.List[str
         p, out, _ = Popen_safe(comp.get_exelist() + ['-print-search-dirs'])
         if p.returncode != 0:
             raise mesonlib.MesonException('Could not calculate system search dirs')
-        out = out.split('\n')[index].lstrip('libraries: =').split(':')
-        return [os.path.normpath(p) for p in out]
+        split = out.split('\n')[index].lstrip('libraries: =').split(':')
+        return [os.path.normpath(p) for p in split]
 
     def get_compiler_system_include_dirs(self, for_machine: MachineChoice) -> T.List[str]:
         for comp in self.coredata.compilers[for_machine].values():
@@ -1016,7 +1028,7 @@ def get_exe_wrapper(self) -> T.Optional[ExternalProgram]:
         return self.exe_wrapper
 
     def has_exe_wrapper(self) -> bool:
-        return self.exe_wrapper and self.exe_wrapper.found()
+        return self.exe_wrapper is not None and self.exe_wrapper.found()
 
     def get_env_for_paths(self, library_paths: T.Set[str], extra_paths: T.Set[str]) -> mesonlib.EnvironmentVariables:
         env = mesonlib.EnvironmentVariables()