fix: check narrowed packs against their own list

After --all-variants, --verify-packs printed "hashes checked during the
build" for the platform-only, truth and required-only packs and compared
none of them, so one missing a file its narrowed list requires passed.
Each pack is now held to the platform list narrowed the way it was built:
source and required_only, read from its name, reach the baseline, the
region grouping and the replay of the core extras.

tests/test_pack_core_extras.py

@@ -87,5 +87,106 @@ class CoreFilesAsTheBuilderPlacesThem(unittest.TestCase):
         )
 
 
+class NarrowedPacksAgainstTheirOwnList(unittest.TestCase):
+    """--verify-packs after --all-variants said "hashes checked during the
+    build" for the five narrowed packs and compared none of them: a narrowed
+    pack missing a file its narrowed list requires passed. Each variant is
+    now held to the platform list narrowed the way it was built."""
+
+    def setUp(self):
+        import common
+        import generate_db
+        import generate_pack
+
+        self.gp = generate_pack
+        tmp = tempfile.TemporaryDirectory(dir=REPO_ROOT / "tmp")
+        self.addCleanup(tmp.cleanup)
+        previous = os.getcwd()
+        os.chdir(tmp.name)
+        self.addCleanup(os.chdir, previous)
+        files: dict = {}
+        for rel in ("bios/p/req.bin", "bios/p/opt.bin", "bios/c/core.bin", "bios/c/extra.bin"):
+            payload = rel.encode()
+            Path(rel).parent.mkdir(parents=True, exist_ok=True)
+            Path(rel).write_bytes(payload)
+            sha1 = hashlib.sha1(payload).hexdigest()
+            files[sha1] = {"path": rel, "name": Path(rel).name, "size": len(payload),
+                           "sha1": sha1, "md5": hashlib.md5(payload).hexdigest(),
+                           "sha256": hashlib.sha256(payload).hexdigest(),
+                           "crc32": "00000001"}
+        self.db = {"files": files, "indexes": generate_db.build_indexes(files, {})}
+        Path("platforms").mkdir()
+        config = {"platform": "P", "verification_mode": "existence", "cores": ["c"],
+                  "systems": {"s": {"files": [
+                      {"name": "req.bin", "destination": "req.bin", "required": True},
+                      {"name": "opt.bin", "destination": "opt.bin", "required": False},
+                  ]}}}
+        Path("platforms/p.yml").write_text(yaml.safe_dump(config), encoding="utf-8")
+        Path("platforms/_registry.yml").write_text(
+            yaml.safe_dump({"platforms": {"p": {"status": "active"}}}), encoding="utf-8"
+        )
+        Path("emulators").mkdir()
+        Path("emulators/c.yml").write_text(yaml.safe_dump({
+            "emulator": "c", "type": "libretro", "systems": ["s"], "files": [
+                {"name": "core.bin", "path": "core.bin", "required": True},
+                {"name": "extra.bin", "path": "extra.bin", "required": False},
+            ]}), encoding="utf-8")
+        common._platform_config_cache.clear()
+        common._emulator_profiles_cache.clear()
+        self.addCleanup(common._platform_config_cache.clear)
+        self.addCleanup(common._emulator_profiles_cache.clear)
+        self.profiles = common.load_emulator_profiles("emulators")
+
+    def _build(self, source: str, required: bool) -> tuple[str, set[str]]:
+        zip_path = self.gp.generate_pack(
+            "p", "platforms", self.db, "bios", "out", emulators_dir="emulators",
+            emu_profiles=self.profiles, source=source, required_only=required,
+            offline=True,
+        )
+        with zipfile.ZipFile(zip_path) as zf:
+            return zip_path, set(zf.namelist()) - {"README.txt"}
+
+    def _check(self, zip_path: str, source: str, required: bool) -> tuple:
+        return packverify.verify_pack_against_platform(
+            zip_path, "p", "platforms", self.db, emulators_dir="emulators",
+            emu_profiles=self.profiles, source=source, required_only=required,
+        )
+
+    def test_every_variant_passes_as_built(self):
+        expected = {
+            ("full", False): {"req.bin", "opt.bin", "core.bin", "extra.bin"},
+            ("full", True): {"req.bin", "core.bin"},
+            ("platform", False): {"req.bin", "opt.bin"},
+            ("platform", True): {"req.bin"},
+            ("truth", False): {"core.bin", "extra.bin"},
+            ("truth", True): {"core.bin"},
+        }
+        for (source, required), members in expected.items():
+            with self.subTest(source=source, required=required):
+                zip_path, held = self._build(source, required)
+                self.assertEqual(held, members)
+                ok, _c, _p, errors, *_rest = self._check(zip_path, source, required)
+                self.assertTrue(ok, errors)
+                self.assertEqual(
+                    self.gp._pack_variant(os.path.basename(zip_path)), (source, required)
+                )
+
+    def test_a_narrowed_pack_missing_a_required_file_fails(self):
+        for source, required, lost in (
+            ("full", True, "core.bin"), ("platform", True, "req.bin"),
+            ("truth", False, "extra.bin"), ("truth", True, "core.bin"),
+        ):
+            with self.subTest(source=source, required=required):
+                zip_path, held = self._build(source, required)
+                with zipfile.ZipFile(zip_path) as zf:
+                    kept = {n: zf.read(n) for n in held if n != lost}
+                with zipfile.ZipFile(zip_path, "w") as zf:
+                    for name, data in kept.items():
+                        zf.writestr(name, data)
+                ok, _c, _p, errors, *_rest = self._check(zip_path, source, required)
+                self.assertFalse(ok)
+                self.assertTrue(any(lost in e for e in errors), errors)
+
+
 if __name__ == "__main__":
     unittest.main()

tests/test_verify_pack_choice.py

@@ -63,8 +63,13 @@ class VerifyPackChoice(unittest.TestCase):
 
         def record(zip_path, platform_name, *a, **kw):
             checked.append((platform_name, os.path.basename(zip_path)))
+            self.variants.append(
+                (kw.get("source", "full"), kw.get("required_only", False))
+            )
             return _ok_result()
 
+        self.variants: list[tuple[str, bool]] = []
+
         with mock.patch.object(self.gp, "verify_pack_against_platform", record):
             self.gp._run_verify_packs(args)
         return checked
@@ -94,26 +99,22 @@ class VerifyPackChoice(unittest.TestCase):
             self._run(self._args())
         self.assertEqual(ctx.exception.code, 1)
 
-    def test_all_variants_names_every_variant_it_built(self):
-        """After --all-variants the check opened the full pack only: the five
-        narrowed packs the same run wrote passed without a line."""
-        import contextlib
-        import io
-
-        names = []
+    def test_all_variants_checks_every_variant_as_it_was_built(self):
+        """After --all-variants the check opened the full pack only, and then
+        said "hashes checked during the build" for the five narrowed packs:
+        one missing a file its narrowed list requires passed. Each is now
+        held to the platform's list narrowed the same way."""
+        names = {}
         for source, required in self.gp.ALL_VARIANTS:
             tags = "".join(
                 tag for tag, _ in self.gp._narrowings(source, None, None, False, required)
             )
-            names.append(f"{self.stem}{tags}_BIOS_Pack.zip")
-            self._touch(names[-1])
-        out = io.StringIO()
-        with contextlib.redirect_stdout(out):
-            checked = self._run(self._args(all_variants=True))
-        self.assertEqual(checked, [("retroarch", f"{self.stem}_BIOS_Pack.zip")])
-        printed = out.getvalue()
-        for name in names[1:]:
-            self.assertIn(f"[{name}]: hashes checked during the build", printed)
+            names[f"{self.stem}{tags}_BIOS_Pack.zip"] = (source, required)
+            self._touch(f"{self.stem}{tags}_BIOS_Pack.zip")
+        checked = self._run(self._args(all_variants=True))
+        self.assertEqual(
+            dict(zip((name for _p, name in checked), self.variants)), names
+        )
 
     def test_the_run_ends_on_a_summary(self):
         """A failing pack was named only above its own error lines, and the