From 95246d81c1cec4a46852118ee884ed516db461e6 Mon Sep 17 00:00:00 2001
From: Kirill Chibisov <contact@kchibisov.com>
Date: Sat, 30 Jul 2022 17:15:57 +0300
Subject: [PATCH] On X11, fix crash when can't disable IME

Fixes #2402.
---
 src/platform_impl/linux/x11/ime/context.rs | 13 ++++----
 src/platform_impl/linux/x11/ime/mod.rs     | 39 ++++++++++++++++------
 2 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/src/platform_impl/linux/x11/ime/context.rs b/src/platform_impl/linux/x11/ime/context.rs
index f0a751b7..a3109d57 100644
--- a/src/platform_impl/linux/x11/ime/context.rs
+++ b/src/platform_impl/linux/x11/ime/context.rs
@@ -1,12 +1,13 @@
-use std::mem::transmute;
+use std::ffi::CStr;
 use std::os::raw::c_short;
-use std::ptr;
 use std::sync::Arc;
+use std::{mem, ptr};
+
+use x11_dl::xlib::{XIMCallback, XIMPreeditCaretCallbackStruct, XIMPreeditDrawCallbackStruct};
+
+use crate::platform_impl::platform::x11::ime::{ImeEvent, ImeEventSender};
 
 use super::{ffi, util, XConnection, XError};
-use crate::platform_impl::platform::x11::ime::{ImeEvent, ImeEventSender};
-use std::ffi::CStr;
-use x11_dl::xlib::{XIMCallback, XIMPreeditCaretCallbackStruct, XIMPreeditDrawCallbackStruct};
 
 /// IME creation error.
 #[derive(Debug)]
@@ -163,7 +164,7 @@ struct PreeditCallbacks {
 impl PreeditCallbacks {
     pub fn new(client_data: ffi::XPointer) -> PreeditCallbacks {
         let start_callback = create_xim_callback(client_data, unsafe {
-            transmute(preedit_start_callback as usize)
+            mem::transmute(preedit_start_callback as usize)
         });
         let done_callback = create_xim_callback(client_data, preedit_done_callback);
         let caret_callback = create_xim_callback(client_data, preedit_caret_callback);
diff --git a/src/platform_impl/linux/x11/ime/mod.rs b/src/platform_impl/linux/x11/ime/mod.rs
index 4125c0ac..746ba9ea 100644
--- a/src/platform_impl/linux/x11/ime/mod.rs
+++ b/src/platform_impl/linux/x11/ime/mod.rs
@@ -120,7 +120,33 @@ impl Ime {
             // Create empty entry in map, so that when IME is rebuilt, this window has a context.
             None
         } else {
-            let event = if with_preedit {
+            let context = unsafe {
+                ImeContext::new(
+                    &self.inner.xconn,
+                    self.inner.im,
+                    window,
+                    None,
+                    with_preedit,
+                    self.inner.event_sender.clone(),
+                )
+                .or_else(|_| {
+                    debug!(
+                        "failed to create an IME context {} preedit support",
+                        if with_preedit { "with" } else { "without" }
+                    );
+                    ImeContext::new(
+                        &self.inner.xconn,
+                        self.inner.im,
+                        window,
+                        None,
+                        !with_preedit,
+                        self.inner.event_sender.clone(),
+                    )
+                })
+            }?;
+
+            // Check the state on the context, since it could fail to enable or disable preedit.
+            let event = if context.is_allowed {
                 ImeEvent::Enabled
             } else {
                 // There's no IME without preedit.
@@ -132,16 +158,7 @@ impl Ime {
                 .send((window, event))
                 .expect("Failed to send enabled event");
 
-            Some(unsafe {
-                ImeContext::new(
-                    &self.inner.xconn,
-                    self.inner.im,
-                    window,
-                    None,
-                    with_preedit,
-                    self.inner.event_sender.clone(),
-                )
-            }?)
+            Some(context)
         };
         self.inner.contexts.insert(window, context);
         Ok(!self.is_destroyed())