fix(backup): exclude snapshots from recovery copy, harden change walk

Migration recovery backups no longer re-copy Folio-Backups (up to 21x bloat). bookChangedSince tracks visited dev:ino so a symlink loop in the book cannot wedge the main-process interval tick. Snapshot toggle check aligned to === false; drop dead home-shortening branch in Settings.

src/main/backup.ts

@@ -49,7 +49,17 @@ export function ensureRecoveryBackup(bookPath: string): string | null {
 
   fs.mkdirSync(getRecoveryRoot(), { recursive: true });
   try {
-    fs.cpSync(key, dest, { recursive: true });
+    // Entry-by-entry, skipping the snapshot dir: snapshots are expendable
+    // copies already retained under their own root — re-backing them up here
+    // would multiply the recovery backup up to (keep + 1)x the book size.
+    // (One cpSync of the root is also refused by Node when the destination
+    // would sit inside the source.)
+    const entries = fs.readdirSync(key);
+    fs.mkdirSync(dest, { recursive: true });
+    for (const e of entries) {
+      if (e === SNAPSHOT_DIR_NAME) continue;
+      fs.cpSync(path.join(key, e), path.join(dest, e), { recursive: true });
+    }
   } catch (err) {
     // A half-copied directory is worse than none — it looks like a good
     // backup. Remove the partial copy, then surface the failure.
@@ -118,6 +128,9 @@ export function bookChangedSince(bookPath: string, sinceMs: number): boolean {
   const key = path.resolve(bookPath);
   const snapRoot = path.join(key, SNAPSHOT_DIR_NAME) + path.sep;
   const stack: string[] = [key];
+  // dev:ino of visited directories — a symlink loop inside the book must not
+  // wedge the main process in an infinite walk on every interval tick.
+  const seen = new Set<string>();
   while (stack.length) {
     const cur = stack.pop() as string;
     let stat: fs.Stats;
@@ -128,6 +141,9 @@ export function bookChangedSince(bookPath: string, sinceMs: number): boolean {
     }
     if (stat.isDirectory()) {
       if ((cur + path.sep).startsWith(snapRoot)) continue;
+      const id = `${stat.dev}:${stat.ino}`;
+      if (seen.has(id)) continue;
+      seen.add(id);
       let kids: string[];
       try {
         kids = fs.readdirSync(cur);

src/main/index.ts

@@ -901,7 +901,7 @@ setInterval(() => {
       snapshotLastRunMs = Date.now();
       return;
     }
-    if (getSetting<boolean>("snapshotsEnabled", SNAPSHOT_DEFAULTS.snapshotsEnabled) !== true) return;
+    if (getSetting<boolean>("snapshotsEnabled", SNAPSHOT_DEFAULTS.snapshotsEnabled) === false) return;
     const intervalMin = clampInt(
       getSetting("snapshotIntervalMin", SNAPSHOT_DEFAULTS.intervalMin),
       SNAPSHOT_DEFAULTS.intervalMin, 1, 1440

src/renderer/book/settings.ts

@@ -48,8 +48,8 @@ export function createSettingsFeature(ctx: BookCtx): SettingsFeature {
   let loaded = false;
 
   function shortPath(p: string): string {
-    const home = (window as unknown as { __folioHome?: string }).__folioHome;
-    if (home && p.startsWith(home)) return "~" + p.slice(home.length);
+    // The backend resolves the path; display it verbatim (no HOME shortening —
+    // the renderer has no reliable home-dir lookup under context isolation).
     return p;
   }
 

tests/run-snapshots-test.mjs

@@ -27,6 +27,9 @@ const {
   createSnapshot,
   pruneSnapshots,
   bookChangedSince,
+  ensureRecoveryBackup,
+  getRecoveryRoot,
+  _resetSessionBackupGuard,
   SNAPSHOT_DIR_NAME,
 } = backup;
 
@@ -88,9 +91,35 @@ settings.delete("snapshotLocation");
 // missing dir -> null, no throw
 ok(createSnapshot(path.join(dir, "nope"), 5) === null, "missing book returns null");
 
+// symlink loop inside the book must not hang the change check
+try {
+  fs.symlinkSync(dir, path.join(dir, "chapters", "loop"), "dir");
+  const t0 = Date.now();
+  const changed = bookChangedSince(dir, Date.now() + 60_000);
+  ok(changed === false && Date.now() - t0 < 5000, "symlink loop terminates without false positive");
+} catch {
+  ok(true, "symlink loop test skipped (no symlink permission)");
+}
+
+// migration recovery backup excludes the snapshot dir (no 21x bloat)
+const home = fs.mkdtempSync(path.join(os.tmpdir(), "folio-fakehome-"));
+const origHome = process.env.HOME;
+process.env.HOME = home;
+try {
+  _resetSessionBackupGuard();
+  const dest = ensureRecoveryBackup(dir);
+  ok(typeof dest === "string" && fs.existsSync(dest), "recovery backup created");
+  ok(fs.existsSync(path.join(dest, "folio.json")), "recovery backup contains folio.json");
+  ok(!fs.existsSync(path.join(dest, SNAPSHOT_DIR_NAME)), "recovery backup excludes snapshots");
+  ok(getRecoveryRoot().startsWith(home), "recovery root honors HOME");
+} finally {
+  process.env.HOME = origHome;
+}
+
 // cleanup
 fs.rmSync(dir, { recursive: true, force: true });
 fs.rmSync(custom, { recursive: true, force: true });
+fs.rmSync(home, { recursive: true, force: true });
 cleanupProj();
 cleanupChap();
 cleanupBackup();