.github/workflows/wai-quantum-studio.yml

@@ -169,7 +169,7 @@ jobs:
           grep -q '^test tests::device_targets_are_listed_shown_and_placed_for_the_page \.\.\. ok$' "$RUNNER_TEMP/test.log" || { echo "::error::the device targets test did not run and pass"; exit 1; }
           grep -q '^test tests::an_answer_is_read_run_and_sealed_for_the_page \.\.\. ok$' "$RUNNER_TEMP/test.log" || { echo "::error::the answer views test did not run and pass"; exit 1; }
           grep -q '^test tests::the_course_is_read_and_checked_in_the_app \.\.\. ok$' "$RUNNER_TEMP/test.log" || { echo "::error::the course test did not run and pass"; exit 1; }
-          for t in an_update_is_held_to_this_build_s_key_and_the_version_it_was_signed_for only_a_copy_installed_by_its_own_installer_updates_itself the_updater_asks_the_release_s_manifest_and_requires_a_signed_version; do
+          for t in a_read_only_volume_is_told_from_a_writable_one an_update_is_held_to_this_build_s_key_and_the_version_it_was_signed_for only_a_copy_installed_by_its_own_installer_updates_itself the_updater_asks_the_release_s_manifest_and_requires_a_signed_version; do
             grep -q "^test tests::$t \.\.\. ok\$" "$RUNNER_TEMP/test.log" || { echo "::error::the update test $t did not run and pass"; exit 1; }
           done
           grep -q '^test tests::a_program_in_another_format_opens_in_the_app \.\.\. ok$' "$RUNNER_TEMP/test.log" || { echo "::error::the formats test did not run and pass"; exit 1; }

wai/CHANGELOG.md

@@ -6,6 +6,17 @@ wire format may change and such changes are recorded here.
 
 ## Unreleased
 
+### wai-quantum-desktop 0.1.1: an app on an external drive updates itself, and one on a disk image does not
+
+The macOS app took any path under `/Volumes` to be its disk image, and any other path not to be. An app kept on an
+external drive was told to move and did not update, while a disk image mounted elsewhere, or a copy Gatekeeper had
+translocated, said it would update itself and could not. It now asks whether the volume it runs from can be written.
+
+- **wai-quantum-desktop 0.1.1:** `update-status` and the updater read the volume's read-only flag, and say why when a
+  copy cannot update. The disk image is the same as before, and nothing else in the app changes. It is the first version
+  with installers for every platform: the 0.1.0 release has none for macOS on Apple silicon, because this check stopped
+  that build.
+
 ### The route record states what a hop delivered by its count and root, so a hop may deliver any number of objects
 
 - **Route record version 3** ([extensions/route-record.md](extensions/route-record.md) §3.4, §5.2, §6, §6.1), on a

wai/wai-quantum-desktop/Cargo.lock

@@ -4477,10 +4477,11 @@ dependencies = [
 
 [[package]]
 name = "wai-quantum-desktop"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "base64 0.22.1",
  "minisign-verify",
+ "rustix",
  "serde_json",
  "tauri",
  "tauri-build",

wai/wai-quantum-desktop/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "wai-quantum-desktop"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2024"
 rust-version = "1.97"
 license = "Apache-2.0"
@@ -29,6 +29,9 @@ tauri-plugin-updater = "2.14.0"
 minisign-verify = "0.3.0"
 base64 = "0.22.1"
 
+[target.'cfg(target_os = "macos")'.dependencies]
+rustix = { version = "1.1.5", features = ["fs"] }
+
 [features]
 default = ["custom-protocol"]
 # The interface served from the bundled build (../quantum-studio/dist), as a release does.

wai/wai-quantum-desktop/src/main.rs

@@ -796,10 +796,10 @@ fn update_key() -> String {
 /// Windows installer. `Err` says why this copy is not one an installer made:
 /// it was built from source, or unpacked by a package manager from the
 /// portable archive, and is updated the way it came.
-fn installed_by(bundle: Option<BundleType>, exe: &Path) -> Result<&'static str, String> {
+fn installed_by(bundle: Option<BundleType>, exe: &Path, read_only: bool) -> Result<&'static str, String> {
     match bundle {
         Some(BundleType::App) if !exe.parent().is_some_and(|d| d.ends_with("Contents/MacOS")) => Err("this copy was built from source, not installed as an app, so it does not update itself".into()),
-        Some(BundleType::App) if exe.starts_with("/Volumes") => Err("this copy runs from its disk image, which cannot be changed; move Quantum Studio to Applications and open it there".into()),
+        Some(BundleType::App) if read_only => Err("this copy runs from its disk image, or another place that cannot be changed; move Quantum Studio to Applications and open it there".into()),
         Some(BundleType::App) => Ok("app"),
         Some(BundleType::AppImage) => Ok("appimage"),
         Some(BundleType::Deb) => Ok("deb"),
@@ -810,14 +810,27 @@ fn installed_by(bundle: Option<BundleType>, exe: &Path) -> Result<&'static str,
     }
 }
 
+/// Whether `path` is on a volume that cannot be written: a mounted disk image, or where
+/// Gatekeeper's App Translocation runs an app it has not seen moved. An app there cannot be
+/// replaced, so it cannot update itself; on any other volume, an external drive among them, it can.
+#[cfg(target_os = "macos")]
+fn on_read_only_volume(path: &Path) -> bool {
+    rustix::fs::statvfs(path).is_ok_and(|v| v.f_flag.contains(rustix::fs::StatVfsMountFlags::RDONLY))
+}
+
+#[cfg(not(target_os = "macos"))]
+fn on_read_only_volume(_path: &Path) -> bool {
+    false
+}
+
 /// Whether this copy updates itself: `Ok` names the installer it came from,
 /// `Err` says why it does not. It does only when this build carries the
 /// release's public key and the copy came from its own installer.
-fn updates_itself(key: &str, bundle: Option<BundleType>, exe: &Path) -> Result<&'static str, String> {
+fn updates_itself(key: &str, bundle: Option<BundleType>, exe: &Path, read_only: bool) -> Result<&'static str, String> {
     if key.trim().is_empty() {
         return Err("this build carries no update key, so it does not update itself; newer versions are on the release page".into());
     }
-    installed_by(bundle, exe)
+    installed_by(bundle, exe, read_only)
 }
 
 /// `update-status`: the installer this copy came from (or null) and whether
@@ -826,8 +839,9 @@ fn updates_itself(key: &str, bundle: Option<BundleType>, exe: &Path) -> Result<&
 fn update_status() -> Result<String, String> {
     let exe = tauri::utils::platform::current_exe().map_err(|e| e.to_string())?;
     let bundle = tauri::utils::platform::bundle_type();
-    let it = updates_itself(&update_key(), bundle.clone(), &exe);
+    let read_only = on_read_only_volume(&exe);
-    Ok(json!({ "installed_by": installed_by(bundle, &exe).ok(), "updates_itself": it.is_ok(), "why_not": it.err() }).to_string())
+    let it = updates_itself(&update_key(), bundle.clone(), &exe, read_only);
+    Ok(json!({ "installed_by": installed_by(bundle, &exe, read_only).ok(), "updates_itself": it.is_ok(), "why_not": it.err() }).to_string())
 }
 
 /// Text that the update manifest carries as base64, decoded.
@@ -866,7 +880,7 @@ struct PendingUpdate(Mutex<Option<tauri_plugin_updater::Update>>);
 #[tauri::command]
 async fn update_check(app: tauri::AppHandle, pending: tauri::State<'_, PendingUpdate>) -> Result<String, String> {
     let exe = tauri::utils::platform::current_exe().map_err(|e| e.to_string())?;
-    if let Err(reason) = updates_itself(&update_key(), tauri::utils::platform::bundle_type(), &exe) {
+    if let Err(reason) = updates_itself(&update_key(), tauri::utils::platform::bundle_type(), &exe, on_read_only_volume(&exe)) {
         return Ok(json!({ "state": "off", "reason": reason }).to_string());
     }
     let current = app.package_info().version.to_string();
@@ -1185,25 +1199,38 @@ mod tests {
     fn only_a_copy_installed_by_its_own_installer_updates_itself() {
         let app = Path::new("/Applications/Quantum Studio.app/Contents/MacOS/wai-quantum-desktop");
         let key = b64(TEST_KEY);
-        assert_eq!(updates_itself(&key, Some(BundleType::App), app), Ok("app"));
+        assert_eq!(updates_itself(&key, Some(BundleType::App), app, false), Ok("app"));
-        assert_eq!(updates_itself(&key, Some(BundleType::AppImage), Path::new("/home/a/Quantum Studio.AppImage")), Ok("appimage"));
+        // An app on an external drive is under /Volumes too, and it can update itself.
-        assert_eq!(updates_itself(&key, Some(BundleType::Deb), Path::new("/usr/bin/wai-quantum-desktop")), Ok("deb"));
+        let external = Path::new("/Volumes/Scratch/Applications/Quantum Studio.app/Contents/MacOS/wai-quantum-desktop");
-        assert_eq!(updates_itself(&key, Some(BundleType::Rpm), Path::new("/usr/bin/wai-quantum-desktop")), Ok("rpm"));
+        assert_eq!(updates_itself(&key, Some(BundleType::App), external, false), Ok("app"));
-        assert_eq!(updates_itself(&key, Some(BundleType::Nsis), Path::new("C:/Users/a/AppData/Local/Quantum Studio/wai-quantum-desktop.exe")), Ok("nsis"));
+        assert_eq!(updates_itself(&key, Some(BundleType::AppImage), Path::new("/home/a/Quantum Studio.AppImage"), false), Ok("appimage"));
+        assert_eq!(updates_itself(&key, Some(BundleType::Deb), Path::new("/usr/bin/wai-quantum-desktop"), false), Ok("deb"));
+        assert_eq!(updates_itself(&key, Some(BundleType::Rpm), Path::new("/usr/bin/wai-quantum-desktop"), false), Ok("rpm"));
+        assert_eq!(updates_itself(&key, Some(BundleType::Nsis), Path::new("C:/Users/a/AppData/Local/Quantum Studio/wai-quantum-desktop.exe"), false), Ok("nsis"));
         let off = |r: Result<&str, String>, why: &str| assert!(r.as_ref().is_err_and(|e| e.contains(why)), "{r:?} should say {why:?}");
-        off(updates_itself("", Some(BundleType::App), app), "carries no update key");
+        off(updates_itself("", Some(BundleType::App), app, false), "carries no update key");
-        off(updates_itself(&key, Some(BundleType::App), Path::new("/src/target/release/wai-quantum-desktop")), "built from source");
+        off(updates_itself(&key, Some(BundleType::App), Path::new("/src/target/release/wai-quantum-desktop"), false), "built from source");
-        off(updates_itself(&key, Some(BundleType::App), Path::new("/Volumes/Quantum Studio/Quantum Studio.app/Contents/MacOS/wai-quantum-desktop")), "disk image");
+        // A disk image can be mounted anywhere: what says so is that the volume cannot be written.
-        off(updates_itself(&key, None, Path::new("C:/Users/a/scoop/apps/wai-quantum-desktop/current/wai-quantum-desktop.exe")), "updated the way it came");
+        off(updates_itself(&key, Some(BundleType::App), Path::new("/private/tmp/m/Quantum Studio.app/Contents/MacOS/wai-quantum-desktop"), true), "disk image");
+        off(updates_itself(&key, None, Path::new("C:/Users/a/scoop/apps/wai-quantum-desktop/current/wai-quantum-desktop.exe"), false), "updated the way it came");
         // How a copy was installed does not depend on the key.
-        assert_eq!(installed_by(Some(BundleType::AppImage), Path::new("/a")), Ok("appimage"));
+        assert_eq!(installed_by(Some(BundleType::AppImage), Path::new("/a"), false), Ok("appimage"));
-        assert!(installed_by(None, Path::new("/a")).is_err());
+        assert!(installed_by(None, Path::new("/a"), false).is_err());
         // This test's own binary was built by cargo: no installer made it.
         let s: Value = serde_json::from_str(&update_status().unwrap()).unwrap();
         assert_eq!((s["installed_by"].as_str(), s["updates_itself"].as_bool()), (None, Some(false)), "{s}");
         assert!(s["why_not"].is_string(), "{s}");
     }
 
+    /// The system volume is read-only on every Mac that runs this, and a temporary folder is not.
+    #[cfg(target_os = "macos")]
+    #[test]
+    fn a_read_only_volume_is_told_from_a_writable_one() {
+        assert!(on_read_only_volume(Path::new("/System/Library/CoreServices")));
+        assert!(!on_read_only_volume(&std::env::temp_dir()));
+        assert!(!on_read_only_volume(Path::new("/no/such/path")), "not known to be read-only");
+    }
+
     /// The updater asks one address, the update manifest the website serves,
     /// over https, and installs only an update signed for the version it
     /// announces; the installers sign updates only when the release asks

wai/wai-quantum-desktop/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Quantum Studio",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "identifier": "science.transaction.quantum-studio",
   "build": {
     "frontendDist": "../quantum-studio/dist"