Validate native CMake build values across cache option types

packaging/steam-frame/verify_image.sh

@@ -60,15 +60,29 @@ for path in license_files:
     if not path.is_file() or not path.stat().st_size:
         raise SystemExit(f'Missing source license notices: {path}')
 
+def verify_native_cmake_settings(cache_text):
+    settings = {}
+    for line in cache_text.splitlines():
+        if not line or line.startswith(('#', '//')):
+            continue
+        declaration, separator, value = line.partition('=')
+        name, type_separator, cache_type = declaration.partition(':')
+        if separator and type_separator and cache_type:
+            settings[name] = value
+    # VR is a STRING option (AUTO/ON/OFF), while the other flags are BOOL.
+    # The configured value determines the build policy, not the cache type.
+    required = {'MOCKTAIL_ENABLE_VR': 'ON',
+                'MOCKTAIL_ENABLE_FSR3': 'OFF',
+                'MOCKTAIL_VR_DIAGNOSTICS': 'OFF'}
+    for name, expected in required.items():
+        if settings.get(name) != expected:
+            raise SystemExit(f'Unexpected build setting: {name}={settings.get(name)!r}; expected {expected}')
+
+
 cache = Path('/work/build-frame-arm64/CMakeCache.txt')
 build_policy = 'source-build-cache'
 if cache.exists():
-    settings = cache.read_text().splitlines()
-    for setting in ('MOCKTAIL_ENABLE_VR:BOOL=ON',
-                    'MOCKTAIL_ENABLE_FSR3:BOOL=OFF',
-                    'MOCKTAIL_VR_DIAGNOSTICS:BOOL=OFF'):
-        if setting not in settings:
-            raise SystemExit(f'Unexpected build setting: {setting}')
+    verify_native_cmake_settings(cache.read_text())
 else:
     # Source-audited release images may omit their disposable compiler cache.
     provenance = json.loads((metadata / 'steam-frame-source.json').read_text())

tests/steam_frame_image_policy_test.py

@@ -0,0 +1,48 @@
+import ast
+from pathlib import Path
+import unittest
+
+script = Path(__file__).resolve().parents[1] / 'packaging/steam-frame/verify_image.sh'
+embedded = script.read_text().split("<<'PY'\n", 1)[1].rsplit("\nPY", 1)[0]
+module = ast.parse(embedded)
+functions = [node for node in module.body if isinstance(node, ast.FunctionDef)
+             and node.name == 'verify_native_cmake_settings']
+scope = {}
+exec(compile(ast.Module(body=functions, type_ignores=[]), str(script), 'exec'), scope)
+verify = scope['verify_native_cmake_settings']
+
+
+class NativeImagePolicy(unittest.TestCase):
+    def test_accepts_real_cmake_string_vr_and_boolean_flags(self):
+        verify("// Native Frame build\nMOCKTAIL_ENABLE_VR:STRING=ON\n"
+               "MOCKTAIL_ENABLE_FSR3:BOOL=OFF\nMOCKTAIL_VR_DIAGNOSTICS:BOOL=OFF\n")
+
+    def test_accepts_equivalent_configured_values_across_cache_types(self):
+        verify("MOCKTAIL_ENABLE_VR:BOOL=ON\nMOCKTAIL_ENABLE_FSR3:UNINITIALIZED=OFF\n"
+               "MOCKTAIL_VR_DIAGNOSTICS:BOOL=OFF\n")
+
+    def test_rejects_incorrect_build_values(self):
+        settings = {'MOCKTAIL_ENABLE_VR': 'ON', 'MOCKTAIL_ENABLE_FSR3': 'OFF',
+                    'MOCKTAIL_VR_DIAGNOSTICS': 'OFF'}
+        for name, invalid in [('MOCKTAIL_ENABLE_VR', 'OFF'),
+                              ('MOCKTAIL_ENABLE_VR', 'AUTO'),
+                              ('MOCKTAIL_ENABLE_FSR3', 'ON'),
+                              ('MOCKTAIL_VR_DIAGNOSTICS', 'ON')]:
+            with self.subTest(name=name, invalid=invalid):
+                changed = dict(settings, **{name: invalid})
+                with self.assertRaises(SystemExit):
+                    verify('\n'.join(f'{key}:STRING={value}' for key, value in changed.items()))
+
+    def test_rejects_missing_or_commented_out_build_settings(self):
+        settings = {'MOCKTAIL_ENABLE_VR': 'ON', 'MOCKTAIL_ENABLE_FSR3': 'OFF',
+                    'MOCKTAIL_VR_DIAGNOSTICS': 'OFF'}
+        for omitted in settings:
+            with self.subTest(omitted=omitted):
+                lines = [f'{key}:STRING={value}' for key, value in settings.items() if key != omitted]
+                lines.append(f'//{omitted}:STRING={settings[omitted]}')
+                with self.assertRaises(SystemExit):
+                    verify('\n'.join(lines))
+
+
+if __name__ == '__main__':
+    unittest.main()