fix(startup): stabilize splash behavior across launch modes

- close parent JVM splash before Linux XIM relaunch to avoid persistent splash during gradle run\n- fix jpackage splash path to match actual app-image layout (APPDIR/../...)\n- disable jpackage splash injection on macOS to avoid codesign failures with --app-content

Author: remiceres

build.gradle.kts

@@ -177,7 +177,11 @@ val jpackageExecutable = packagingJavaHome.map { javaHome ->
 val startupSplashImage = file("src/main/resources/images/startup-splash-primer-dark.png")
 val startupSplashEnabled = startupSplashImage.exists()
 val startupSplashJvmOption = "-splash:${startupSplashImage.absolutePath}"
-val startupSplashPackagedJvmOption = "-splash:\$APPDIR/${startupSplashImage.name}"
+// jpackage launcher resolves $APPDIR to the jars folder (lib/app on Linux app-image).
+// `--app-content` currently lands in lib/, so splash path is one directory above $APPDIR.
+val startupSplashPackagedJvmOption = "-splash:\$APPDIR/../${startupSplashImage.name}"
+// macOS jpackage can fail codesign when additional app content is injected via --app-content.
+val startupSplashJpackageEnabled = startupSplashEnabled && hostOs != "macos"
 
 /*
  * Per-platform icon resolution for jpackage.
@@ -403,8 +407,8 @@ tasks.register<Exec>("jpackageCurrentPlatform") {
     inputs.property("jpackageAppName", jpackageAppName)
     inputs.property("jpackageAppVersion", jpackageAppVersion)
     inputs.property("jpackageIconPath", jpackageIcon.absolutePath)
-    inputs.property("startupSplashEnabled", startupSplashEnabled)
-    if (startupSplashEnabled) {
+    inputs.property("startupSplashJpackageEnabled", startupSplashJpackageEnabled)
+    if (startupSplashJpackageEnabled) {
         inputs.file(startupSplashImage)
         inputs.property("startupSplashPackagedJvmOption", startupSplashPackagedJvmOption)
     }
@@ -433,7 +437,7 @@ tasks.register<Exec>("jpackageCurrentPlatform") {
             "--java-options", Meta.nativeAccessOption
         )
 
-        if (startupSplashEnabled) {
+        if (startupSplashJpackageEnabled) {
             args("--app-content", startupSplashImage.absolutePath)
             args("--java-options", startupSplashPackagedJvmOption)
         }
@@ -472,8 +476,8 @@ if (hostOs == "windows") {
         inputs.property("jpackageAppName", jpackageAppName)
         inputs.property("jpackageAppVersion", jpackageAppVersion)
         inputs.property("jpackageIconPath", jpackageIcon.absolutePath)
-        inputs.property("startupSplashEnabled", startupSplashEnabled)
-        if (startupSplashEnabled) {
+        inputs.property("startupSplashJpackageEnabled", startupSplashJpackageEnabled)
+        if (startupSplashJpackageEnabled) {
             inputs.file(startupSplashImage)
             inputs.property("startupSplashPackagedJvmOption", startupSplashPackagedJvmOption)
         }
@@ -502,7 +506,7 @@ if (hostOs == "windows") {
                 "--java-options", Meta.nativeAccessOption
             )
 
-            if (startupSplashEnabled) {
+            if (startupSplashJpackageEnabled) {
                 args("--app-content", startupSplashImage.absolutePath)
                 args("--java-options", startupSplashPackagedJvmOption)
             }

src/main/java/fr/inria/corese/gui/core/bootstrap/LinuxInputMethodBootstrap.java

@@ -1,5 +1,6 @@
 package fr.inria.corese.gui.core.bootstrap;
 
+import java.awt.SplashScreen;
 import java.io.File;
 import java.io.IOException;
 import java.lang.management.ManagementFactory;
@@ -72,6 +73,7 @@ public static void relaunchWithXimIfNeeded(String[] args) {
 		pb.inheritIO();
 
 		try {
+			closeNativeSplashIfPresent();
 			Process child = pb.start();
 			int exitCode = child.waitFor();
 			System.exit(exitCode);
@@ -136,4 +138,15 @@ private static String extractEntryPointFromSunCommand() {
 		int spaceIdx = trimmed.indexOf(' ');
 		return spaceIdx < 0 ? trimmed : trimmed.substring(0, spaceIdx);
 	}
+
+	private static void closeNativeSplashIfPresent() {
+		try {
+			SplashScreen splash = SplashScreen.getSplashScreen();
+			if (splash != null) {
+				splash.close();
+			}
+		} catch (UnsupportedOperationException _) {
+			// No native splash active.
+		}
+	}
 }