Print all causes when reporting UserExceptions.

And report errors and traces to stdout to avoid interference between stdout/stderr, both of which are captured by the builder.

(cherry picked from commit a146c153a33baf53fffcaee9a9a3a5f76c8f7039)

Author: fniephaus

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/NativeImageGeneratorRunner.java

@@ -43,7 +43,6 @@
 import java.util.Set;
 import java.util.TimerTask;
 import java.util.concurrent.ForkJoinPool;
-import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
 import org.graalvm.collections.Pair;
@@ -557,7 +556,7 @@ private int buildImage(ImageClassLoader classLoader) {
                 NativeImageGeneratorRunner.reportFatalError(e, "FallbackImageRequest while building fallback image.");
                 return ExitStatus.BUILDER_ERROR.getValue();
             }
-            reportUserException(e, parsedHostedOptions, LogUtils::warning);
+            reportUserException(e, parsedHostedOptions);
             return ExitStatus.FALLBACK_IMAGE.getValue();
         } catch (ParsingError e) {
             NativeImageGeneratorRunner.reportFatalError(e);
@@ -584,7 +583,7 @@ private int buildImage(ImageClassLoader classLoader) {
             }
 
             if (pee.getExceptions().size() > 1) {
-                System.err.println(pee.getExceptions().size() + " fatal errors detected:");
+                System.out.println(pee.getExceptions().size() + " fatal errors detected:");
             }
             for (Throwable exception : pee.getExceptions()) {
                 NativeImageGeneratorRunner.reportFatalError(exception);
@@ -670,8 +669,8 @@ public static void printCPUFeatures(Platform platform) {
      * @param e error to be reported.
      */
     protected static void reportFatalError(Throwable e) {
-        System.err.print("Fatal error: ");
-        e.printStackTrace();
+        System.out.print("Fatal error: ");
+        e.printStackTrace(System.out);
     }
 
     /**
@@ -681,8 +680,8 @@ protected static void reportFatalError(Throwable e) {
      * @param msg message to report.
      */
     protected static void reportFatalError(Throwable e, String msg) {
-        System.err.print("Fatal error: " + msg);
-        e.printStackTrace();
+        System.out.print("Fatal error: " + msg);
+        e.printStackTrace(System.out);
     }
 
     /**
@@ -691,7 +690,7 @@ protected static void reportFatalError(Throwable e, String msg) {
      * @param msg error message that is printed.
      */
     public static void reportUserError(String msg) {
-        System.err.println("Error: " + msg);
+        System.out.println("Error: " + msg);
     }
 
     /**
@@ -701,20 +700,28 @@ public static void reportUserError(String msg) {
      * @param parsedHostedOptions
      */
     public static void reportUserError(Throwable e, OptionValues parsedHostedOptions) {
-        reportUserException(e, parsedHostedOptions, NativeImageGeneratorRunner::reportUserError);
+        reportUserException(e, parsedHostedOptions);
     }
 
-    private static void reportUserException(Throwable e, OptionValues parsedHostedOptions, Consumer<String> report) {
+    private static void reportUserException(Throwable e, OptionValues parsedHostedOptions) {
         if (e instanceof UserException ue) {
             for (String message : ue.getMessages()) {
-                report.accept(message);
+                reportUserError(message);
             }
         } else {
-            report.accept(e.getMessage());
+            reportUserError(e.getMessage());
+        }
+        Throwable current = e.getCause();
+        while (current != null) {
+            System.out.print("Caused by: ");
+            current.printStackTrace(System.out);
+            current = current.getCause();
         }
         if (parsedHostedOptions != null && NativeImageOptions.ReportExceptionStackTraces.getValue(parsedHostedOptions)) {
-            e.printStackTrace();
+            System.out.print("Internal exception: ");
+            e.printStackTrace(System.out);
         }
+        System.out.flush();
     }
 
     public int build(ImageClassLoader imageClassLoader) {