Restore the browser page on relaunch, not the last edited file

A relaunch session always re-opened the last edited file, even when the
app was closed sitting on the browser page. The snapshot now records
which page the app was on (SessionState.InBrowser/BrowserPath); the cmd
layer lands back in the browser at the saved directory on relaunch
(falling back to the startup directory if it has vanished) instead of
calling BeginRestore. Browser-page snapshots clear File, which also
makes the editor->browser transition an urgent save, so the
back-in-browser state hits disk immediately. Legacy session files (no
InBrowser key) unmarshal to false and restore the editor exactly as
before.

Verified on emulator and phone: editor sessions still restore the file
(cursor/scroll/font), browser sessions land in the browser at the saved
dir; legacy files keep the old behavior. New e2e regression test
TestRestore_BrowserPageSession.

cmd/pad/main.go

@@ -112,18 +112,30 @@ func run(w *app.Window) error {
 	// file, cursor, scroll, selection and find bar state. The cmd layer owns
 	// the file (sessionFilePath, per platform); the logic layer owns the
 	// snapshot (editor.SessionState) and calls the saver rate-limited and at
-	// Shutdown. Restoring re-opens the last file straight into the editor.
+	// Shutdown. A session taken on the editor page re-opens the last file
+	// straight into the editor; one taken on the browser page lands back in
+	// the browser at the saved directory.
 	sessPath := sessionFilePath()
 	logic.SetSessionSaver(newSessionSaver(sessPath))
 	if sess, ok := loadSession(sessPath); ok {
-		log.Printf("restoring session: file=%s cursor=%d scroll=%v find=%q", sess.File, sess.Cursor, sess.Scroll, sess.FindQuery)
-		logic.BeginRestore(sess)
-		// The find bar's input is a main-owned widget and the input source of
-		// truth: seed it with the restored query so its first frame matches
-		// the logic-side query (an empty widget would forward "" and clear
-		// the restored query).
-		if sess.FindQuery != "" {
-			findEditor.SetText(sess.FindQuery)
+		if sess.InBrowser {
+			log.Printf("restoring session: browser path=%q", sess.BrowserPath)
+			// The saved directory may have vanished (deleted, synced away):
+			// fall back to the startup directory rather than pointing the
+			// browser at a dead path.
+			if fi, err := os.Stat(sess.BrowserPath); err == nil && fi.IsDir() {
+				logic.BeginBrowserRestore(sess.BrowserPath)
+			}
+		} else {
+			log.Printf("restoring session: file=%s cursor=%d scroll=%v find=%q", sess.File, sess.Cursor, sess.Scroll, sess.FindQuery)
+			logic.BeginRestore(sess)
+			// The find bar's input is a main-owned widget and the input source
+			// of truth: seed it with the restored query so its first frame
+			// matches the logic-side query (an empty widget would forward ""
+			// and clear the restored query).
+			if sess.FindQuery != "" {
+				findEditor.SetText(sess.FindQuery)
+			}
 		}
 	}
 
@@ -435,7 +447,9 @@ func newSessionSaver(path string) func(editor.SessionState) {
 
 // loadSession reads and sanity-checks the relaunch session file (spec §7).
 // ok=false when there is no session, it is corrupt, or nothing is restorable
-// — in which case the app starts in the browser as before.
+// — in which case the app starts in the browser at the startup directory
+// as before. Browser-page sessions carry no file; an editor-page session
+// (the pre-InBrowser legacy shape included) needs one.
 func loadSession(path string) (editor.SessionState, bool) {
 	b, err := os.ReadFile(path)
 	if err != nil {
@@ -465,7 +479,7 @@ func loadSession(path string) (editor.SessionState, bool) {
 	if s.ScrollSub < 0 {
 		s.ScrollSub = 0
 	}
-	if s.File == "" {
+	if !s.InBrowser && s.File == "" {
 		return editor.SessionState{}, false
 	}
 	return s, true

doc/spec.md

@@ -141,10 +141,13 @@ elsewhere.
 
 ### 2.4 State restoration on relaunch
 
-- On launch, Pad re-opens the file from the last session and lands straight
-  on the editor page, restoring the cursor, scroll position, live selection,
-  and the find bar (query, open/closed, current match). A relaunch therefore
-  never requires re-browsing to the last file.
+- On launch, Pad lands exactly where the last session ended. If the app was
+  in the editor, it re-opens the last file straight on the editor page,
+  restoring the cursor, scroll position, live selection, and the find bar
+  (query, open/closed, current match) — a relaunch therefore never requires
+  re-browsing to the last file. If the app was on the browser page, it lands
+  back in the browser at the saved directory (`InBrowser`/`BrowserPath` in
+  the snapshot; a deleted directory falls back to the startup directory).
 - The scroll position is persisted as the LOGICAL line at the viewport top
   plus the sub-line remainder (the raw pixel offset is kept too, for
   pre-line-coordinate session files). The pixel offset alone is not

internal/editor/session.go

@@ -1,7 +1,8 @@
 // State restoration on relaunch (spec §7).
 //
 // The restorable state is a small snapshot (SessionState) the logic
-// goroutine takes on demand: the last opened file, the cursor byte offset,
+// goroutine takes on demand: which page the app was on, and, on the editor
+// page, the last opened file, the cursor byte offset,
 // the editor scroll offset, the live selection, and the find bar (query,
 // open/closed, current match). The search RESULTS themselves are not part
 // of the snapshot: on relaunch they are regenerated by re-scanning the
@@ -65,6 +66,14 @@ type SessionState struct {
 	FindCurByte int     // start byte of the current find match (-1 = none)
 	// AppFontScale is the app-local pinch font scale (0 = default 1.0).
 	AppFontScale float64
+	// InBrowser records that the app was sitting on the BROWSER page when
+	// the snapshot was taken: the relaunch must land back in the browser at
+	// BrowserPath instead of re-opening the last file in the editor. The
+	// flag (not "File == "") disambiguates from pre-flag session files, whose
+	// absence of the key unmarshals to false and restores the editor as
+	// before. When true, File is "" and the editor-side fields are stale.
+	InBrowser bool
+	BrowserPath string
 }
 
 // SetSessionSaver registers the callback that persists snapshots (the cmd
@@ -115,8 +124,20 @@ func (l *Logic) SnapshotSession() SessionState {
 		// Dp discriminator used on restore).
 		scrollSub = r0 / float64(lh)
 	}
+	inBrowser := l.state.page == BrowserPage
+	file := e.Filename
+	if inBrowser {
+		// Nothing to restore in the editor: leaving the last file in File
+		// would let a reader that ignores InBrowser re-open it, and the
+		// editor->browser transition is then also an urgent save (File
+		// change), so the "back in the browser" state hits disk immediately
+		// instead of waiting out the rate limit.
+		file = ""
+	}
 	return SessionState{
-		File:         e.Filename,
+		File:         file,
+		InBrowser:    inBrowser,
+		BrowserPath:  l.state.Browser.CurrentPath,
 		Cursor:       cur,
 		Scroll:       float64(s.ScrollOffset),
 		ScrollLine:   scrollLine,
@@ -254,6 +275,18 @@ func (l *Logic) BeginRestore(s SessionState) {
 	l.emitFrame() // show the editor page now; the content loads async
 }
 
+// BeginBrowserRestore makes a relaunch land in the browser at dirPath
+// instead of the startup directory (see SessionState.InBrowser). It is
+// synchronous: the directory is dispatched for its index by Run, which reads
+// CurrentPath, so it must be called after NewLogic and before Run (the cmd
+// layer does both before starting the logic goroutine). An empty dirPath
+// keeps the startup directory.
+func (l *Logic) BeginBrowserRestore(dirPath string) {
+	if dirPath != "" {
+		l.state.Browser.CurrentPath = dirPath
+	}
+}
+
 // abortRestore ends a restore without landing it (the user opened another
 // file, the read failed, or the file is too large): clears the pending
 // snapshot so session saving resumes (see saveSessionIfChanged). The editor

internal/test/e2e/restore_test.go

@@ -833,3 +833,55 @@ drainDone:
 		t.Fatal("timed out: selection appearance was not saved immediately (urgent path)")
 	}
 }
+
+// TestRestore_BrowserPageSession covers the relaunch bug where a session
+// ended on the browser page still re-opened the last edited file: a
+// snapshot taken on the browser page must mark InBrowser (with the browser
+// directory and no file), and a relaunch handed that snapshot must land
+// back in the browser at the saved directory.
+func TestRestore_BrowserPageSession(t *testing.T) {
+	// Snapshot on the browser page.
+	h := e2e.NewHarnessWithDefaults()
+	defer h.Cleanup()
+	if err := h.WithState(func(st *editor.State) {
+		st.Browser.CurrentPath = "/Documents/Work"
+	}); err != nil {
+		t.Fatalf("WithState: %v", err)
+	}
+	v, err := h.Inspect(func(st *editor.State) any {
+		return h.Logic().SnapshotSession()
+	})
+	if err != nil {
+		t.Fatalf("Inspect: %v", err)
+	}
+	sess := v.(editor.SessionState)
+	if !sess.InBrowser {
+		t.Fatalf("browser-page snapshot: InBrowser = false, want true: %+v", sess)
+	}
+	if sess.File != "" {
+		t.Errorf("browser-page snapshot: File = %q, want \"\"", sess.File)
+	}
+	if sess.BrowserPath != "/Documents/Work" {
+		t.Errorf("browser-page snapshot: BrowserPath = %q, want \"/Documents/Work\"", sess.BrowserPath)
+	}
+
+	// Relaunch with that session: land in the browser at the saved dir.
+	h2 := e2e.NewHarness()
+	defer h2.Cleanup()
+	h2.Logic().BeginBrowserRestore(sess.BrowserPath)
+	h2.Run()
+	h2.SendConfig(780, 1688)
+	h2.SendScale(2.0)
+	if _, err := e2e.WaitForNewFrame(h2, 0, 5*time.Second); err != nil {
+		t.Fatalf("timeout waiting for frames: %v", err)
+	}
+	v, err = h2.Inspect(func(st *editor.State) any {
+		return st.Page() == editor.BrowserPage && st.Browser.CurrentPath == sess.BrowserPath
+	})
+	if err != nil {
+		t.Fatalf("Inspect: %v", err)
+	}
+	if !v.(bool) {
+		t.Fatal("relaunch with a browser session did not land on the browser page at the saved directory")
+	}
+}