CanWang
909ac66c0a
## Summary - Fix crash on startup when the X11 server supports XInput < 2.4 (e.g. XInput 2.3) - Gesture event mask bits (pinch begin/update/end) are now only requested when the server advertises XInput >= 2.4 - Zed previously failed to open any window on affected systems, printing `Zed failed to open a window: X11 XiSelectEvents failed` ## Self-Review Checklist: - [x] I've reviewed my own diff for quality, security, and reliability - [x] Unsafe blocks (if any) have justifying comments - [x] The content is consistent with the [UI/UX checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist) - [x] Tests cover the new/changed behavior - [x] Performance impact has been considered and is acceptable ## Problem On X11 systems where the XInput extension version is older than 2.4, Zed crashes immediately on startup with: ``` Zed failed to open a window: X11 XiSelectEvents failed. Caused by: X11 error X11Error { error_kind: Value, error_code: 2, sequence: 277, bad_value: 27, minor_opcode: 46, major_opcode: 131, extension_name: Some("XInputExtension"), request_name: Some("XISelectEvents") } ``` This makes Zed completely unusable on any X11 display server that only supports XInput 2.3 or earlier, which includes many current Ubuntu 20.04/22.04 systems, remote X11 sessions, and VNC/Xvfb setups. ### Root cause During window creation, `X11WindowState::new` calls `XISelectEvents` with an event mask that unconditionally includes gesture event bits (`GESTURE_PINCH_BEGIN`, `GESTURE_PINCH_UPDATE`, `GESTURE_PINCH_END`). These gesture events were introduced in **XInput 2.4**. When the X server only supports XInput 2.3 (or older), it does not recognize these mask bits and rejects the entire `XISelectEvents` request with a `BadValue` error. This is fatal because the error is propagated up and prevents the window from being created. A comment in the original code stated: > If the server only supports an older version, gesture events simply won't be delivered. This is incorrect. The X11 protocol does **not** silently ignore unknown mask bits in `XISelectEvents` — it rejects the whole request. ### How XInput version negotiation works The client calls `XIQueryVersion(2, 4)` to announce the highest version it supports. The server responds with the highest version **it** supports (e.g. `2.3`). The client is then responsible for not using features beyond the negotiated version. The existing code ignored the server's response and used 2.4 features unconditionally. ## Fix ### Approach Check the XInput version returned by the server. Only include gesture event mask bits in `XISelectEvents` when the negotiated version is >= 2.4. On older servers, basic input events (motion, button press/release, enter, leave) still work normally — only touchpad pinch gestures are unavailable. ### Changed files **`crates/gpui_linux/src/linux/x11/client.rs`** 1. Added `supports_xinput_gestures: bool` field to `X11ClientState`. 2. After the existing `xinput_xi_query_version(2, 4)` call, compute whether the server version is >= 2.4: ```rust let supports_xinput_gestures = xinput_version.major_version > 2 || (xinput_version.major_version == 2 && xinput_version.minor_version >= 4); ``` 3. Added an `info!` log line reporting the detected XInput version and gesture support status. 4. Pass `supports_xinput_gestures` through `open_window` into `X11Window::new`. **`crates/gpui_linux/src/linux/x11/window.rs`** 1. Added `supports_xinput_gestures: bool` parameter to both `X11Window::new` and `X11WindowState::new`. 2. The `XISelectEvents` call now builds the event mask conditionally: - Always includes: `MOTION`, `BUTTON_PRESS`, `BUTTON_RELEASE`, `ENTER`, `LEAVE` - Only when `supports_xinput_gestures` is true: `GESTURE_PINCH_BEGIN`, `GESTURE_PINCH_UPDATE`, `GESTURE_PINCH_END` ### What is NOT changed - The gesture event **handlers** in `client.rs` (`XinputGesturePinchBegin`, `XinputGesturePinchUpdate`, `XinputGesturePinchEnd`) are left as-is. They simply won't be triggered on servers without gesture support, since the events are never registered. - No behavioral change on systems with XInput >= 2.4 — gesture events continue to work exactly as before. ## Testing | Test | Before fix | After fix | |------|-----------|-----------| | `./target/release/zed .` on XInput 2.3 | Immediate crash (exit code 1) | Window opens successfully (runs until killed) | | XInput version detection | Version queried but response ignored | Version checked and logged | Verified on an X11 system with XInput 2.3 (X.Org 1.20.13, Ubuntu 20.04). ## Test plan - [x] Build succeeds (`cargo build --release`) - [x] Zed launches and opens a window on XInput 2.3 system - [x] No regression on the basic input event path (motion, clicks, enter/leave still registered) - [ ] Verify gesture pinch events still work on a system with XInput >= 2.4 Release Notes: - Fixed Zed failing to start on X11 systems with XInput version older than 2.4, which includes many Linux distributions and remote desktop setups.
Zed
Welcome to Zed, a high-performance, multiplayer code editor from the creators of Atom and Tree-sitter.
Installation
On macOS, Linux, and Windows you can download Zed directly or install Zed via your local package manager (macOS/Linux/Windows).
Other platforms are not yet available:
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Developing Zed
Contributing
See CONTRIBUTING.md for ways you can contribute to Zed.
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Licensing
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