Make Unix launch scripts executable (#319)

Author: shartte

src/main/java/net/neoforged/moddevgradle/internal/CreateLaunchScriptTask.java

@@ -3,8 +3,13 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.PosixFileAttributeView;
+import java.nio.file.attribute.PosixFilePermission;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.stream.Collectors;
 import javax.inject.Inject;
@@ -190,10 +195,30 @@ private void writeLaunchScriptForUnix(List<String> javaCommand) throws IOExcepti
                 "(cd " + escapeShellArg(getWorkingDirectory().get()) + "; exec "
                         + javaCommand.stream().map(this::escapeShellArg).collect(Collectors.joining(" ")) + ")");
 
+        Path destination = getLaunchScript().get().getAsFile().toPath();
         FileUtils.writeStringSafe(
-                getLaunchScript().get().getAsFile().toPath(),
+                destination,
                 String.join("\n", lines),
                 StandardCharsets.UTF_8);
+
+        makeExecutable(destination);
+    }
+
+    private static void makeExecutable(Path destination) throws IOException {
+        var permissionView = Files.getFileAttributeView(destination, PosixFileAttributeView.class);
+        if (permissionView != null) {
+            var perm = new HashSet<>(permissionView.readAttributes().permissions());
+            if (perm.contains(PosixFilePermission.OWNER_READ)) {
+                perm.add(PosixFilePermission.OWNER_EXECUTE);
+            }
+            if (perm.contains(PosixFilePermission.GROUP_READ)) {
+                perm.add(PosixFilePermission.GROUP_EXECUTE);
+            }
+            if (perm.contains(PosixFilePermission.OTHERS_READ)) {
+                perm.add(PosixFilePermission.OTHERS_EXECUTE);
+            }
+            permissionView.setPermissions(perm);
+        }
     }
 
     private String escapeShellArg(String text) {