fix(editor): open the launched file when the window restores its last tabs

Starting OpenIDEA with a file opened LightEdit (or the file's project) and
showed the tabs of the last session without the file. Restoring the saved
tabs replaced the tab state, which counted as the user activating another
tab, so the pending open of the launched file was dropped as stale. Restoring
a session no longer counts as an activation: the launched file opens next to
the restored tabs and becomes the active one.

src/editor/core/controller.test.ts

@@ -262,6 +262,24 @@ describe("EditorController", () => {
     useProject.setState({ lightEdit: false });
   });
 
+  it("opens a file requested while the LightEdit session is being restored", async () => {
+    ctrl = new EditorController(createMemoryBackend({ "/x/a.txt": "a", "/y/b.md": "b", "/z/launch.lua": "l" }));
+    ctrl.start();
+    useProject.setState({ lightEdit: true });
+    await ctrl.openFile("/x/a.txt", { focus: false });
+    await ctrl.openFile("/y/b.md", { focus: false });
+    useProject.setState({ lightEdit: false });
+    // A launch with a file path: LightEdit starts and the file opens before the old tabs are back.
+    useProject.setState({ lightEdit: true });
+    await ctrl.openFile("/z/launch.lua", { focus: false });
+    expect(openFilePaths(useTabs.getState())).toEqual(["/x/a.txt", "/y/b.md", "/z/launch.lua"]);
+    const s = useTabs.getState();
+    const active = s.panes[s.activePane]!;
+    expect(active.tabs.find((t) => t.id === active.active)?.input.path).toBe("/z/launch.lua");
+    await ctrl.closeEverything();
+    useProject.setState({ lightEdit: false });
+  });
+
   it("closes a tab by its input key", async () => {
     ctrl = new EditorController(createMemoryBackend());
     ctrl.start();

src/editor/core/controller.ts

@@ -237,6 +237,8 @@ export class EditorController implements SlotHost {
   private selectionRequests = new Map<string, number>();
   private activationGeneration = 0;
   private admitting = false;
+  /** Tabs restored from a saved session: not a user's activation, so a pending open still activates its tab. */
+  private restoring = false;
   private closeRequests = 0;
   private projectTransition: Promise<void> = Promise.resolve();
 
@@ -269,6 +271,7 @@ export class EditorController implements SlotHost {
         prevTabs = s;
         if (
           !this.admitting &&
+          !this.restoring &&
           (s.activePane !== prev.activePane || s.panes[s.activePane]?.active !== prev.panes[prev.activePane]?.active)
         )
           ++this.activationGeneration;
@@ -486,7 +489,12 @@ export class EditorController implements SlotHost {
       pane.tabs = pane.tabs.map((tab) => (documentLifecycle(tab.input, kinds) ? { ...tab, preview: false } : tab));
     this.restoredViews = new Map(Object.entries(session.files));
     this.restoredTabs = new Set(Object.values(state.panes).flatMap((p) => p.tabs.map((t) => t.id)));
-    useTabs.setState(state, true);
+    this.restoring = true;
+    try {
+      useTabs.setState(state, true);
+    } finally {
+      this.restoring = false;
+    }
     for (const pane of Object.values(state.panes)) if (pane.active) void this.ensureSlot(pane.active);
   }