fix(electron): re-probe mpv after a late login shell PATH either way

A Linux mpv probe that ran on the inherited PATH can be wrong in both
directions: the login shell PATH may add mpv or drop the directory the
inherited one found it in. forgetLinuxMpvExecutableProbe() now clears a
found result as well as a missing one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/electron-backend/src/app/events/embedded-mpv.events.spec.ts

@@ -9,7 +9,7 @@ const mockEmbeddedMpvService = {
     prepareAddon: jest.fn(),
     getSupport: jest.fn(),
     willProbeLinuxMpvExecutable: jest.fn(() => false),
-    forgetMissingLinuxMpvExecutable: jest.fn(),
+    forgetLinuxMpvExecutableProbe: jest.fn(),
     setPaused: jest.fn(),
 };
 const mockSessionOptions = {
@@ -108,12 +108,12 @@ describe('EmbeddedMpvEvents IPC handlers', () => {
                 settle(true);
                 await expect(support).resolves.toEqual({ supported: true });
                 expect(
-                    mockEmbeddedMpvService.forgetMissingLinuxMpvExecutable
+                    mockEmbeddedMpvService.forgetLinuxMpvExecutableProbe
                 ).not.toHaveBeenCalled();
             }
         );
 
-        it('re-probes a missing mpv once a lookup that ran out finally answers', async () => {
+        it('re-probes mpv once a lookup that ran out finally answers', async () => {
             mockEmbeddedMpvService.willProbeLinuxMpvExecutable.mockReturnValue(
                 true
             );
@@ -126,13 +126,13 @@ describe('EmbeddedMpvEvents IPC handlers', () => {
                 getIpcMainHandler(EMBEDDED_MPV_SUPPORT)({})
             ).resolves.toEqual({ supported: false });
             expect(
-                mockEmbeddedMpvService.forgetMissingLinuxMpvExecutable
+                mockEmbeddedMpvService.forgetLinuxMpvExecutableProbe
             ).not.toHaveBeenCalled();
 
             settleLookup();
             await new Promise<void>((resolve) => setImmediate(resolve));
             expect(
-                mockEmbeddedMpvService.forgetMissingLinuxMpvExecutable
+                mockEmbeddedMpvService.forgetLinuxMpvExecutableProbe
             ).toHaveBeenCalledTimes(1);
         });
 

apps/electron-backend/src/app/events/embedded-mpv.events.ts

@@ -81,10 +81,10 @@ async function afterLoginShellPathIfProbing<T>(check: () => T): Promise<T> {
         return check();
     }
     // The lookup ran out of budget, so this probe sees the inherited PATH.
-    // Once the shell does answer, a "missing" result is probed again.
+    // Once the shell does answer, the result is probed again.
     const result = check();
     void whenLoginShellPathSettled().then(() =>
-        getService().forgetMissingLinuxMpvExecutable()
+        getService().forgetLinuxMpvExecutableProbe()
     );
     return result;
 }

apps/electron-backend/src/app/services/embedded-mpv-native.service.spec.ts

@@ -394,7 +394,7 @@ describe('EmbeddedMpvNativeService power blocker', () => {
             expect(service.willProbeLinuxMpvExecutable()).toBe(false);
         });
 
-        it('probes a missing mpv again after it is forgotten, but keeps a found one', () => {
+        it('probes mpv again after a missing or a found result is forgotten', () => {
             Object.defineProperty(process, 'platform', { value: 'linux' });
             process.env.DISPLAY = ':0';
             delete process.env.WAYLAND_DISPLAY;
@@ -403,14 +403,15 @@ describe('EmbeddedMpvNativeService power blocker', () => {
             mockRuntimeUsable();
 
             expect(service.getSupport().supported).toBe(false);
-            service.forgetMissingLinuxMpvExecutable();
+            service.forgetLinuxMpvExecutableProbe();
             expect(service.willProbeLinuxMpvExecutable()).toBe(true);
 
             mockSpawnSync.mockReturnValue({ status: 0 });
             service.getSupport();
             expect(mockSpawnSync).toHaveBeenCalledTimes(2);
-            service.forgetMissingLinuxMpvExecutable();
             expect(service.willProbeLinuxMpvExecutable()).toBe(false);
+            service.forgetLinuxMpvExecutableProbe();
+            expect(service.willProbeLinuxMpvExecutable()).toBe(true);
         });
 
         it('predicts no probe for the frame-copy engine or native Wayland', () => {

apps/electron-backend/src/app/services/embedded-mpv-native.service.ts

@@ -394,14 +394,13 @@ export class EmbeddedMpvNativeService {
     }
 
     /**
-     * Drops a cached "mpv missing" result, so the next support check probes
-     * again (a found mpv stays cached). For a probe that ran before the
-     * login shell PATH arrived.
+     * Drops the cached `mpv --version` result, found or missing, so the next
+     * support check probes again. For a probe that ran before the login
+     * shell PATH arrived: that PATH may add mpv or leave out the directory
+     * the inherited one found it in.
      */
-    forgetMissingLinuxMpvExecutable(): void {
-        if (this.cachedLinuxMpvExecutableReason) {
-            this.cachedLinuxMpvExecutableReason = undefined;
-        }
+    forgetLinuxMpvExecutableProbe(): void {
+        this.cachedLinuxMpvExecutableReason = undefined;
     }
 
     getSupport(): EmbeddedMpvSupport {