fix: check system_titles at the boundary

A list or a number among the titles passed validation and raised later,
in --system matching or the interface.

install.ps1

@@ -11,7 +11,7 @@
 
     $ErrorActionPreference = "Stop"
     $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-    $defaultInstallSha256 = "5fedfbf308ba04a174ce0682380a28150b6fe5eab514a605e3b318193ce37c7a"
+    $defaultInstallSha256 = "6d8af0dbca6697ba71692e5e482c8a16d9e8b9896652fec722d9c84f23bba047"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -3069,6 +3069,15 @@ def _validate_manifest(data: object, plat: str) -> dict:
             _check_tags(mapping, key, field)
             if mapping[key] is None:
                 raise ValueError(f"invalid {field} for {key}")
+    titles = data.get("system_titles")
+    if titles is not None:
+        if not isinstance(titles, dict) or len(titles) > MAX_MANIFEST_FILES:
+            raise ValueError("invalid system_titles")
+        for key, title in titles.items():
+            if not isinstance(key, str) or not 0 < len(key) <= 256:
+                raise ValueError("invalid system_titles key")
+            if not isinstance(title, str) or not 0 < len(title) <= 256:
+                raise ValueError(f"invalid system_titles for {key}")
 
     copies = data.get("standalone_copies", [])
     if not isinstance(copies, list) or len(copies) > 10_000:

install.sh

@@ -18,7 +18,7 @@ esac
 TEMP_INSTALLER=""
 TEMP_DIRECTORY=""
 DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-DEFAULT_INSTALL_SHA256="5fedfbf308ba04a174ce0682380a28150b6fe5eab514a605e3b318193ce37c7a"
+DEFAULT_INSTALL_SHA256="6d8af0dbca6697ba71692e5e482c8a16d9e8b9896652fec722d9c84f23bba047"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

tests/test_install_selection.py

@@ -493,6 +493,19 @@ class TheBoundaryChecksTheNewFields(unittest.TestCase):
             with self.subTest(field=field, value=bad), self.assertRaises(ValueError):
                 install._validate_manifest(manifest, "retroarch")
 
+    def test_the_system_titles(self):
+        """A title is read as text by --system and the interface: a list or
+        a number there raised mid-run instead of at the boundary."""
+        good = self._manifest()
+        good["system_titles"] = {"sony-playstation": "Sony PlayStation"}
+        install._validate_manifest(good, "retroarch")
+        for bad in (["x"], {"s": ["Sony"]}, {"s": None}, {"s": 5}, {"s": ""},
+                    {"": "Sony"}, {"s": "x" * 257}, {"s" * 257: "Sony"}):
+            manifest = self._manifest()
+            manifest["system_titles"] = bad
+            with self.subTest(value=bad), self.assertRaises(ValueError):
+                install._validate_manifest(manifest, "retroarch")
+
 
 class _QuietHandler(http.server.SimpleHTTPRequestHandler):
     def log_message(self, format, *args):  # noqa: A002 - stdlib signature