fix: keep the listing in the no-platform hint

--list-systems, --list-cores, --list-emulators and --list-targets with nothing detected were answered with an install command that dropped the listing and added --dest. The hint now names the platform and keeps the listing.

install.ps1

@@ -11,7 +11,7 @@
 
     $ErrorActionPreference = "Stop"
     $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-    $defaultInstallSha256 = "c462ff5c1c755b269b680f6e1c4c22ef58b7ae9b92679444634c35d248cc4267"
+    $defaultInstallSha256 = "108b168f54fdc795322152b655fcca3793968cc8e4629287e64f2bd51fa13aa7"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -3968,7 +3968,7 @@ def _default_dest(os_type: str, platform_name: str) -> Path | None:
     return DEFAULT_DESTS.get(platform_name)
 
 
-def _manual_usage_hint(os_type: str) -> list[str]:
+def _manual_usage_hint(os_type: str, listing: str = "") -> list[str]:
     """How to name the platform and directory when nothing is detected.
 
     In the form the run was started with: a one-liner user has no
@@ -3980,6 +3980,15 @@ def _manual_usage_hint(os_type: str) -> list[str]:
     }.get(os_type, "~/.config/retroarch/system")
     hint = Invocation()
     hint.os_type, hint.options = os_type, _INVOCATION.options
+    if listing:
+        # A listing reads a platform's list and writes nothing: --dest is
+        # not needed, and a rebuilt install command dropped the listing
+        # and started a 6.5 GB download.
+        return [
+            "  Name the platform whose list to print, for example:",
+            f"    {hint.command('retroarch', None)} {listing}",
+            f"  The platforms: {hint.launcher()} --list-platforms",
+        ]
     return [
         "  Use --platform and --dest to specify manually, for example:",
         f"    {hint.command('retroarch', example)}",
@@ -4743,7 +4752,12 @@ def _install(args: argparse.Namespace, real_stdout: TextIO) -> None:
         if not platforms:
             print("  No supported platform detected.")
             if not interactive or listing:
-                for line in _manual_usage_hint(os_type):
+                asked = next((flag for flag, on in (
+                    ("--list-systems", args.list_systems), ("--list-cores", args.list_cores),
+                    ("--list-emulators", args.list_emulators),
+                    ("--list-targets", args.list_targets),
+                ) if on), "")
+                for line in _manual_usage_hint(os_type, asked):
                     print(line)
                 sys.exit(1)
             platforms = _prompt_manual_platform(os_type)

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="c462ff5c1c755b269b680f6e1c4c22ef58b7ae9b92679444634c35d248cc4267"
+DEFAULT_INSTALL_SHA256="108b168f54fdc795322152b655fcca3793968cc8e4629287e64f2bd51fa13aa7"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

tests/test_install.py

@@ -3446,6 +3446,19 @@ class HintsGiveTheUsersOwnCommandBack(unittest.TestCase):
             hint = "\n".join(install._manual_usage_hint("linux"))
         self.assertIn("python3 install.py --platform retroarch", hint)
 
+    def test_a_listing_hint_keeps_the_listing(self):
+        """--list-systems with nothing detected was answered with a full
+        install command: the listing flag gone, a --dest added."""
+        home = Path(_tempdir(self))
+        env = {**os.environ, "HOME": str(home), "RETROBIOS_OS": "linux",
+               "RETROBIOS_BOOTSTRAP": ""}
+        for flag in ("--list-systems", "--list-cores", "--list-emulators", "--list-targets"):
+            with self.subTest(flag=flag):
+                proc = _install_run(env, flag, "--no-input")
+                self.assertEqual(proc.returncode, 1, proc.stdout + proc.stderr)
+                self.assertIn(f"python3 install.py --platform retroarch {flag}", proc.stdout)
+                self.assertNotIn("--dest", proc.stdout)
+
     def test_the_write_advice_keeps_the_narrowing(self):
         self._record("--system", "atari-lynx", "--region", "us")
         install._INVOCATION.os_type = "linux"