## Description
Screen capture in Stage Tamagotchi is denied before it ever reaches the
desktop picker: `navigator.mediaDevices.getDisplayMedia()` resolves with
`NotAllowedError: Permission denied`, so the vision screen-capture panel
can list sources but never start a stream.
The cause is in `shouldGrantElectronPermission`. Electron reports
**screen capture as the `media` permission**, not as `display-capture`,
and it only appends `audio`/`video` to `details.mediaTypes` for *device*
capture — so a `getDisplayMedia()` request arrives as `media` with an
**empty** `mediaTypes` list
([`web_contents_permission_helper.cc#L249-L274`](https://github.com/electron/electron/blob/v41.2.1/shell/browser/web_contents_permission_helper.cc#L249-L274)).
The handler took an early return for every `media` operation and
required audio-only details, so display capture was rejected before the
allowlisted `display-capture` entry could be consulted:
```ts
if (permission === 'media')
return shouldGrantAudioCapturePermission(webContents, permission, requestingOrigin, details)
return LOCAL_APP_PERMISSION_NAMES.has(permission) && shouldGrantLocalAppPermission(...)
```
The fix resolves a `media` operation that declares no device media type
back to `display-capture`, so the existing allowlist and local-frame
checks decide the outcome — which is what `LOCAL_APP_PERMISSION_NAMES`
already intended:
```ts
const allowlistPermission = isDisplayCaptureMediaPermission(permission, details) ? 'display-capture' : permission
return LOCAL_APP_PERMISSION_NAMES.has(allowlistPermission)
&& shouldGrantLocalAppPermission(webContents, requestingOrigin, details)
```
Camera and microphone operations always report their device media type
(`['video']`, `['audio']`, `mediaType: 'audio'`), so they never take
this path and stay exactly as strict as before. Remote frames are still
rejected, because the local-frame check is unchanged and still applies
to display capture.
Three regression tests are added: screen capture from a local page is
granted, screen capture from a remote page is rejected, and a camera
request is still denied now that it shares the `media` permission.
## Linked Issues
Closes#2177
## Additional Context
- **Regression range.** This was introduced by #2002 (`5e8bf75`,
2026-07-10), which added the permission allowlist. Nothing on the
failing path is platform-specific — the `media` vs `display-capture`
mismatch is in Electron's browser process — so although the issue was
reported on Windows, screen capture has been broken on macOS and Linux
since that commit too. Worth noting for anyone triaging similar reports.
- **Detection signal.** The predicate keys on `mediaTypes.length === 0`
rather than on the absence of the field, so a `media` operation with
*no* `mediaTypes` at all (e.g. permission *checks*, which send
`mediaType: 'unknown'` instead) is not silently promoted to display
capture. That keeps the change to exactly the shape Electron documents
for `getDisplayMedia()` requests.
- **Deliberately out of scope.** #2104 (camera snapshot denied) is a
policy decision — whether the camera should join the allowlist — not
this bug, and #2132 (`systemPreferences.getMediaAccessStatus` undefined
on Linux) is unrelated. Happy to follow up on either if you'd like them
addressed.
- **Second layer still applies.** `setDisplayMediaRequestHandler` in
`packages/electron-screen-capture` is only installed inside the
`setSource` mutex window, so a grant here still requires the renderer to
have selected a source first. This change does not widen that.
- **Verification.** `media-permissions.test.ts` goes 16/16 → 19/19; with
only the tests applied, the new local-screen-capture case fails as
expected. Type checking and the repo ESLint config both pass clean on
the two touched files.
---------
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
