fix: list a platform's files without installing it

--list-systems, --list-cores and --list-targets read the manifest and write nothing, yet with --platform bizhawk they went through the portable-install refusal and stopped asking for --dest. Someone checking BizHawk's firmware before downloading BizHawk got an error. A listing now runs whether the platform is installed or not.

install.ps1

@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "98bc3ac3442126a44534c4c6817dfda2f680e9f9a5aa499efb81cccebd692ec2"
+$defaultInstallSha256 = "84b6a006895a34929d99cfd890f028c2ae09e134385dfd10cc955288daaf4260"
 $maximumInstallerBytes = 2MB
 $installerExit = 0
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -3677,6 +3677,11 @@ def _install(args: argparse.Namespace, real_stdout: TextIO) -> None:
         matched = [(n, p) for n, p in detected if n == args.platform]
         if matched:
             platforms = matched
+        elif listing:
+            # A listing reads the manifest and writes nothing: no folder is
+            # needed, and asking BizHawk's for one refused a question asked
+            # before downloading BizHawk.
+            platforms = [(args.platform, _default_dest(os_type, args.platform) or Path.cwd())]
         elif args.platform in PORTABLE_ONLY:
             # A portable emulator reads the folder beside its executable:
             # any default would be a folder it never opens.

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="98bc3ac3442126a44534c4c6817dfda2f680e9f9a5aa499efb81cccebd692ec2"
+DEFAULT_INSTALL_SHA256="84b6a006895a34929d99cfd890f028c2ae09e134385dfd10cc955288daaf4260"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

tests/test_install_selection.py

@@ -665,5 +665,25 @@ class ACoreWithNothingHeldIsAnOmission(unittest.TestCase):
         self.assertEqual(omitted, [])
 
 
+class AListingNeedsNoInstall(unittest.TestCase):
+    """--list-systems with --platform bizhawk stopped on "not found, name it
+    with --dest": a question asked before downloading BizHawk was refused."""
+
+    def test_bizhawk_lists_without_a_folder(self):
+        with FakeRepository() as repo:
+            manifest = json.loads((repo.root / "install" / "retroarch.json").read_text())
+            manifest["platform"] = "bizhawk"
+            (repo.root / "install" / "bizhawk.json").write_text(json.dumps(manifest))
+            env = {**repo.env(), "HOME": str(repo.root / "home"), "USERPROFILE": str(repo.root / "home")}
+            proc = subprocess.run(
+                [sys.executable, str(REPO_ROOT / "install.py"), "--platform", "bizhawk",
+                 "--list-systems"],
+                env=env, capture_output=True, text=True, timeout=60, check=False,
+                stdin=subprocess.DEVNULL,
+            )
+            self.assertEqual(proc.returncode, 0, proc.stdout + proc.stderr)
+            self.assertIn("nintendo-gba", proc.stdout)
+
+
 if __name__ == "__main__":
     unittest.main()