JBR-9817 Wayland: text-input-unstable-v3: Japanese input text partially highlighted in search

Working around https://gitlab.gnome.org/GNOME/mutter/-/issues/3547.

Author: OnePatchGuy

src/java.desktop/unix/classes/sun/awt/wl/im/text_input_unstable_v3/CurrentDesktopInfo.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2026 JetBrains s.r.o.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.awt.wl.im.text_input_unstable_v3;
+
+import sun.awt.UNIXToolkit;
+
+import java.awt.Toolkit;
+import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+final class CurrentDesktopInfo {
+
+    private CurrentDesktopInfo() {}
+
+
+    public static boolean isGnome() {
+        Boolean result = isGnome.get();
+
+        if (result == null) {
+            synchronized (CurrentDesktopInfo.class) {
+                if (Toolkit.getDefaultToolkit() instanceof UNIXToolkit unixToolkit) {
+                    result = "gnome".equals(unixToolkit.getDesktop());
+                } else {
+                    result = false;
+                }
+
+                isGnome.set(result);
+            }
+
+            return result;
+        }
+
+        return result;
+    }
+    // {@code null} if not initialized yet
+    private static final AtomicReference<Boolean> isGnome = new AtomicReference<>(null);
+
+    /** negative if couldn't obtain or the desktop is not GNOME */
+    public static int getGnomeShellMajorVersion() {
+        Integer result = gnomeVersion.get();
+
+        if (result == null) {
+            synchronized (CurrentDesktopInfo.class) {
+                if (!isGnome()) {
+                    result = -1;
+                } else if (Toolkit.getDefaultToolkit() instanceof UNIXToolkit unixToolkit) {
+                    try {
+                        result = Objects.requireNonNullElse(unixToolkit.getGnomeShellMajorVersion(), -1);
+                    } catch (Exception ignored) {
+                        result = -1;
+                    }
+                } else {
+                    result = -1;
+                }
+
+                gnomeVersion.set(result);
+            }
+
+            return result;
+        }
+
+        return result;
+    }
+    // {@code null} if not initialized yet, negative if couldn't obtain or the desktop is not GNOME
+    private static final AtomicReference<Integer> gnomeVersion = new AtomicReference<>(null);
+}

src/java.desktop/unix/classes/sun/awt/wl/im/text_input_unstable_v3/WLInputMethodZwpTextInputV3.java

@@ -1196,6 +1196,29 @@ private IncomingChanges wlGetIncomingChanges() {
         return wlIncomingChanges;
     }
 
+
+    private JavaPreeditString wlFixPreeditStringIfBroken(final JavaPreeditString preeditString) {
+        if (preeditString == null) {
+            return null;
+        }
+
+        final boolean isGNOME46OrBelow;
+        if (CurrentDesktopInfo.isGnome()) {
+            final int gnomeVersion = CurrentDesktopInfo.getGnomeShellMajorVersion();
+            isGNOME46OrBelow = gnomeVersion >= 0 && gnomeVersion <= 46;
+        } else {
+            isGNOME46OrBelow = false;
+        }
+
+        // https://gitlab.gnome.org/GNOME/mutter/-/issues/3547.
+        // Working around it here by resetting cursor_end to cursor_begin.
+        if (isGNOME46OrBelow) {
+            return new JavaPreeditString(preeditString.text(), preeditString.cursorBeginCodeUnit(), preeditString.cursorBeginCodeUnit());
+        }
+        return preeditString;
+    }
+
+
     /** Called by {@link ClientComponentCaretPositionTracker} */
     boolean wlUpdateCursorRectangle(final boolean forceUpdate) {
         assert EventQueue.isDispatchThread() : "Method must only be invoked on EDT";
@@ -1427,6 +1450,7 @@ private void zwp_text_input_v3_onDone(long doneSerial) {
                         );
                     }
                 }
+                preeditStringToApplyInitializer = wlFixPreeditStringIfBroken(preeditStringToApplyInitializer);
                 preeditStringToApply = Objects.requireNonNullElse(preeditStringToApplyInitializer, PropertiesInitials.PREEDIT_STRING);
 
                 JavaCommitString commitStringToApplyInitializer;