options: fix typing issues stemming from initialize_from_top_level_project_call

Machine files provide a `Mapping[OptionKey, ElementaryOptionValues]`,
but the expectation listed was that they provided options in the raw DSL
format.

2 files changed, 15 insertions, 7 deletions

diff --git a/mesonbuild/options.py b/mesonbuild/options.py
index 4339f7773..8a7b7ec3b 100644
--- a/mesonbuild/options.py
+++ b/mesonbuild/options.py
@@ -6,6 +6,7 @@ from __future__ import annotations
 from collections import OrderedDict
 from itertools import chain
 import argparse
+import copy
 import dataclasses
 import itertools
 import os
@@ -1236,21 +1237,28 @@ class OptionStore:
     def first_handle_prefix(self,
                             project_default_options: T.Union[T.List[str], OptionStringLikeDict],
                             cmd_line_options: T.Union[T.List[str], OptionStringLikeDict],
-                            machine_file_options: T.Union[T.List[str], OptionStringLikeDict]) \
+                            machine_file_options: T.Mapping[OptionKey, ElementaryOptionValues]) \
             -> T.Tuple[T.Union[T.List[str], OptionStringLikeDict],
                        T.Union[T.List[str], OptionStringLikeDict],
-                       T.Union[T.List[str], OptionStringLikeDict]]:
+                       T.MutableMapping[OptionKey, ElementaryOptionValues]]:
+        # Copy to avoid later mutation
+        nopref_machine_file_options = T.cast(
+            'T.MutableMapping[OptionKey, ElementaryOptionValues]', copy.copy(machine_file_options))
+
         prefix = None
         (possible_prefix, nopref_project_default_options) = self.prefix_split_options(project_default_options)
         prefix = prefix if possible_prefix is None else possible_prefix
-        (possible_prefix, nopref_native_file_options) = self.prefix_split_options(machine_file_options)
-        prefix = prefix if possible_prefix is None else possible_prefix
+
+        possible_prefixv = nopref_machine_file_options.pop(OptionKey('prefix'), None)
+        assert possible_prefixv is None or isinstance(possible_prefixv, str), 'mypy: prefix from machine file was not a string?'
+        prefix = prefix if possible_prefixv is None else possible_prefixv
+
         (possible_prefix, nopref_cmd_line_options) = self.prefix_split_options(cmd_line_options)
         prefix = prefix if possible_prefix is None else possible_prefix
 
         if prefix is not None:
             self.hard_reset_from_prefix(prefix)
-        return (nopref_project_default_options, nopref_cmd_line_options, nopref_native_file_options)
+        return (nopref_project_default_options, nopref_cmd_line_options, nopref_machine_file_options)
 
     def hard_reset_from_prefix(self, prefix: str) -> None:
         prefix = self.sanitize_prefix(prefix)
@@ -1268,7 +1276,7 @@ class OptionStore:
     def initialize_from_top_level_project_call(self,
                                                project_default_options_in: T.Union[T.List[str], OptionStringLikeDict],
                                                cmd_line_options_in: T.Union[T.List[str], OptionStringLikeDict],
-                                               machine_file_options_in: T.Union[T.List[str], OptionStringLikeDict]) -> None:
+                                               machine_file_options_in: T.Mapping[OptionKey, ElementaryOptionValues]) -> None:
         first_invocation = True
         (project_default_options, cmd_line_options, machine_file_options) = self.first_handle_prefix(project_default_options_in,
                                                                                                      cmd_line_options_in,
diff --git a/unittests/optiontests.py b/unittests/optiontests.py
index d02119a06..3b3ffc98e 100644
--- a/unittests/optiontests.py
+++ b/unittests/optiontests.py
@@ -32,7 +32,7 @@ class OptionTests(unittest.TestCase):
         vo = UserStringOption(k.name, 'An option of some sort', default_value)
         optstore.add_system_option(k.name, vo)
         self.assertEqual(optstore.get_value_for(k), default_value)
-        optstore.initialize_from_top_level_project_call([f'someoption={new_value}'], {}, {})
+        optstore.initialize_from_top_level_project_call({OptionKey('someoption'): new_value}, {}, {})
         self.assertEqual(optstore.get_value_for(k), new_value)
 
     def test_parsing(self):