make EnvironmentVariablesObject a proper holder

Currently, EnvironmentVariablesObject is a strange
holder-that's-not-a-holder. This has implicaitons for things that expect
to get an EnvironmentVariables object, as we can't automatically
unholder it, and instead have to to manually do so. Now we can
automatically unholder it, which makes everything much nicer.

1 files changed, 19 insertions, 24 deletions

diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index ec5c75c..d640e65 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -42,7 +42,6 @@ from .mesonmain import MesonMain
 from .dependencyfallbacks import DependencyFallbacksHolder
 from .interpreterobjects import (
     SubprojectHolder,
-    EnvironmentVariablesObject,
     ConfigurationDataObject,
     Test,
     RunProcess,
@@ -396,6 +395,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             build.Data: OBJ.DataHolder,
             build.InstallDir: OBJ.InstallDirHolder,
             build.IncludeDirs: OBJ.IncludeDirsHolder,
+            build.EnvironmentVariables: OBJ.EnvironmentVariablesObject,
             compilers.RunResult: compilerOBJ.TryRunResultHolder,
             dependencies.ExternalLibrary: OBJ.ExternalLibraryHolder,
             coredata.UserFeatureOption: OBJ.FeatureOptionHolder,
@@ -1723,19 +1723,14 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
                   kwargs: 'kwargs.FuncTest') -> None:
         self.add_test(node, args, kwargs, True)
 
-    def unpack_env_kwarg(self, kwargs: T.Union[EnvironmentVariablesObject, T.Dict[str, str], T.List[str]]) -> build.EnvironmentVariables:
-        envlist = kwargs.get('env', EnvironmentVariablesObject())
-        if isinstance(envlist, EnvironmentVariablesObject):
-            env = envlist.vars
-        elif isinstance(envlist, dict):
-            FeatureNew.single_use('environment dictionary', '0.52.0', self.subproject)
-            env = EnvironmentVariablesObject(envlist)
-            env = env.vars
-        else:
-            # Convert from array to environment object
-            env = EnvironmentVariablesObject(envlist)
-            env = env.vars
-        return env
+    def unpack_env_kwarg(self, kwargs: T.Union[build.EnvironmentVariables, T.Dict[str, 'TYPE_var'], T.List['TYPE_var'], str]) -> build.EnvironmentVariables:
+        envlist = kwargs.get('env')
+        if envlist is None:
+            return build.EnvironmentVariables()
+        msg = ENV_KW.validator(envlist)
+        if msg:
+            raise InvalidArguments(f'"env": {msg}')
+        return ENV_KW.convertor(envlist)
 
     def make_test(self, node: mparser.BaseNode,
                   args: T.Tuple[str, T.Union[build.Executable, build.Jar, ExternalProgram, mesonlib.File]],
@@ -2361,17 +2356,17 @@ This will become a hard error in the future.''' % kwargs['input'], location=self
 
     @noKwargs
     @noArgsFlattening
-    def func_environment(self, node, args, kwargs):
-        if len(args) > 1:
-            raise InterpreterException('environment takes only one optional positional arguments')
-        elif len(args) == 1:
+    @typed_pos_args('environment', optargs=[(str, list, dict)])
+    def func_environment(self, node: mparser.FunctionNode, args: T.Tuple[T.Union[None, str, T.List['TYPE_var'], T.Dict[str, 'TYPE_var']]],
+                         kwargs: 'TYPE_kwargs') -> build.EnvironmentVariables:
+        init = args[0]
+        if init is not None:
             FeatureNew.single_use('environment positional arguments', '0.52.0', self.subproject)
-            initial_values = args[0]
-            if not isinstance(initial_values, dict) and not isinstance(initial_values, list):
-                raise InterpreterException('environment first argument must be a dictionary or a list')
-        else:
-            initial_values = {}
-        return EnvironmentVariablesObject(initial_values, self.subproject)
+            msg = ENV_KW.validator(init)
+            if msg:
+                raise InvalidArguments(f'"environment": {msg}')
+            return ENV_KW.convertor(init)
+        return build.EnvironmentVariables()
 
     @typed_pos_args('join_paths', varargs=str, min_varargs=1)
     @noKwargs