From 8892432866daf1d5c446befaa5842981fdfa92a8 Mon Sep 17 00:00:00 2001
From: Abdessamad Derraz <3028866+Abdess@users.noreply.github.com>
Date: Fri, 16 Oct 2026 22:09:12 +0200
Subject: [PATCH] fix: fail install --check when files are missing

---
 install.ps1           | 2 +-
 install.py            | 5 +++++
 install.sh            | 2 +-
 tests/test_install.py | 8 ++++++++
 wiki/installer.md     | 3 ++-
 5 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/install.ps1 b/install.ps1
index e79f313e..6a62c50f 100644
--- a/install.ps1
+++ b/install.ps1
@@ -8,7 +8,7 @@ param(
 
 $ErrorActionPreference = "Stop"
 $defaultInstallUrl = "https://raw.githubusercontent.com/Abdess/retrobios/main/install.py"
-$defaultInstallSha256 = "f9e46dd53fc7501ddf18ece3fc7f08dbf738c617fec93707c6a7f40e8db39673"
+$defaultInstallSha256 = "e0d8fad4e7e55afa57c412e98726992d82b92286b752c9a8cce0978f0a355127"
 $maximumInstallerBytes = 2MB
 $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }
 $temporary = $null
diff --git a/install.py b/install.py
index 47bbe1d4..f3d7125d 100644
--- a/install.py
+++ b/install.py
@@ -2702,6 +2702,7 @@ def _install(args: argparse.Namespace, real_stdout) -> None:
     total_bytes = 0
     total_seconds = 0.0
     total_declined = 0
+    check_pending = 0
     failures: list[tuple[str, str]] = []
     installed_paths: list[Path] = []
 
@@ -2881,6 +2882,7 @@ def _install(args: argparse.Namespace, real_stdout) -> None:
         if args.check:
             if to_download:
                 print(f"\n  {len(to_download)} files need downloading.")
+                check_pending += len(to_download)
             else:
                 print("\n  All files up to date.")
             continue
@@ -2960,6 +2962,9 @@ def _install(args: argparse.Namespace, real_stdout) -> None:
             )
 
     sys.stdout = real_stdout
+    # A check scripted as `--check && launch` reads the exit code only.
+    if args.check and check_pending:
+        sys.exit(1)
     if not args.check and not listing and not args.dry_run:
         _report_outcome(
             installed_paths,
diff --git a/install.sh b/install.sh
index 91c71c1c..71727445 100755
--- a/install.sh
+++ b/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="f9e46dd53fc7501ddf18ece3fc7f08dbf738c617fec93707c6a7f40e8db39673"
+DEFAULT_INSTALL_SHA256="e0d8fad4e7e55afa57c412e98726992d82b92286b752c9a8cce0978f0a355127"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {
diff --git a/tests/test_install.py b/tests/test_install.py
index b90c76df..f766052f 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -946,6 +946,14 @@ class InstallerStaysOnPython38AndTheStdlib(unittest.TestCase):
                 self.assertEqual(proc.returncode, 0, proc.stdout + proc.stderr)
                 self.assertNotIn("Traceback", proc.stderr)
         self.assertTrue((dest / "lynxboot.img").is_file())
+        # A check is scripted as `--check && launch`: missing files fail it.
+        proc = subprocess.run(
+            base + ["--dest", str(home / "empty"), "--system", "atari-lynx", "--check"],
+            cwd=REPO_ROOT, env=env, capture_output=True, text=True, timeout=300,
+            check=False,
+        )
+        self.assertEqual(proc.returncode, 1, proc.stdout + proc.stderr)
+        self.assertIn("need downloading", proc.stdout)
 
     def test_no_syntax_a_312_parser_lets_through(self):
         """Parenthesized context managers (3.9) and f-strings reusing their
diff --git a/wiki/installer.md b/wiki/installer.md
index 3f3ff76f..d961da5e 100644
--- a/wiki/installer.md
+++ b/wiki/installer.md
@@ -224,7 +224,8 @@ what the options name, everything by default.
 | `--standalone-copies` | Also copy into detected standalone emulator directories |
 | `--help`, `-h` | Print the option list and exit |
 
-`--check` reads the same file list, hashes the destination and exits. Without
+`--check` reads the same file list, hashes the destination and exits, with
+code 1 when a file is missing or does not match and 0 when every one does. Without
 it, a file already present with the expected hash is left untouched, and one
 whose contents do not match is re-downloaded and replaced by the verified copy.
 Files the list does not name are never read, moved or deleted.