CLI now supports renamed main sketch file via sketch.properties .

app/src/processing/app/Sketch.java

@@ -1320,10 +1320,13 @@ static protected File findMain(File folder, List<Mode> modeList) {
       String main = props.get("main");
       if (main != null) {
         File mainFile = new File(folder, main);
-        if (!mainFile.exists()) {
+        if (mainFile.exists()) {
+          return mainFile;
+        }
+        else {
           System.err.println(main + " does not exist inside " + folder);
           // Fall through to the code below in case we can recover.
-          // Not removing the bad entry since this is a find() method.
+
         }
       }
     } catch (IOException e) {

app/src/processing/app/ui/Editor.java

@@ -2256,20 +2256,26 @@ public boolean checkModified() {
    * shouldn't rely on any of its variables being initialized already.
    */
   protected void handleOpenInternal(String path) throws EditorException {
-    // Prior to 4.0 beta 6, a lot of logic happened here that was
-    // instead moved into Base. Probably was here so that other Modes
-    // could override the behavior, but that was too messy. [fry 220206]
+  try {
+    File sketchFolder = new File(path);
 
-    try {
-      sketch = new Sketch(path, this);
-    } catch (IOException e) {
-      throw new EditorException("Could not create the sketch.", e);
+    // Try to locate main file using sketch.properties or fallback
+    File mainFile = Sketch.findMain(sketchFolder, Base.getModeList());
+    if (mainFile == null) {
+      throw new EditorException("No valid main .pde file found in " + sketchFolder);
     }
 
-    header.rebuild();
-    updateTitle();
+    // Use the parent folder of the main file
+    sketch = new Sketch(mainFile.getParentFile(), this);
+
+  } catch (IOException e) {
+    throw new EditorException("Could not create the sketch.", e);
   }
 
+  header.rebuild();
+  updateTitle();
+}
+
 
   /**
    * Set the title of the PDE window based on the current sketch, i.e.

app/test/processing/app/CLITest.kt

@@ -47,4 +47,20 @@ class CLITest {
         println("Done running CLI with arguments: $args (Result: $result)")
 
     }
-}
+    fun runCLIAndCapture(vararg args: String): String {
+        val argLine = args.joinToString(" ")
+        println("Running CLI with arguments: $argLine")
+
+        val process = ProcessBuilder("./gradlew", "run", "--args=$argLine", "--quiet")
+            .directory(File(System.getProperty("user.dir")).resolve("../../../"))
+            .redirectErrorStream(true)
+            .start()
+
+        val output = process.inputStream.bufferedReader().readText()
+        val exitCode = process.waitFor()
+
+        println("Done running CLI with arguments: $argLine (Exit code: $exitCode)")
+        return output
+    }
+
+}