[MNG-7846] Break out of endless loop (#1206)

This is most probably "just" about broken Throwable implementations. Some override getCause but does not perform checks to what it was inited as "this" means "not yet inited" actually. Backport of 36db1e3 --- https://issues.apache.org/jira/browse/MNG-7846
apache · Jul 19, 2023 · 2963769 · 2963769
1 parent 3f37e6a
commit 2963769
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Showing 4 changed files with 35 additions and 3 deletions.
diff --git a/maven-core/src/main/java/org/apache/maven/exception/DefaultExceptionHandler.java b/maven-core/src/main/java/org/apache/maven/exception/DefaultExceptionHandler.java
@@ -222,7 +222,8 @@ private boolean isNoteworthyException(Throwable exception) {
     private String getMessage(String message, Throwable exception) {
         String fullMessage = (message != null) ? message : "";
 
-        for (Throwable t = exception; t != null; t = t.getCause()) {
+        // To break out of possible endless loop when getCause returns "this"
+        for (Throwable t = exception; t != null && t != t.getCause(); t = t.getCause()) {
             String exceptionMessage = t.getMessage();
 
             if (t instanceof AbstractMojoExecutionException) {

diff --git a/maven-core/src/test/java/org/apache/maven/exception/DefaultExceptionHandlerTest.java b/maven-core/src/test/java/org/apache/maven/exception/DefaultExceptionHandlerTest.java
@@ -20,6 +20,7 @@
 
 import java.io.IOException;
 import java.net.ConnectException;
+import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.maven.model.Plugin;
 import org.apache.maven.plugin.MojoExecution;
@@ -95,4 +96,32 @@ public void testHandleExceptionNoClassDefFoundErrorNull() {
         String expectedReference = "http://cwiki.apache.org/confluence/display/MAVEN/PluginContainerException";
         assertEquals(expectedReference, summary.getReference());
     }
+
+    @Test
+    public void testHandleExceptionLoopInCause() {
+        // Some broken exception that does return "this" as getCause
+        AtomicReference<Throwable> causeRef = new AtomicReference<>(null);
+        Exception cause2 = new RuntimeException("loop") {
+            @Override
+            public synchronized Throwable getCause() {
+                return causeRef.get();
+            }
+        };
+        causeRef.set(cause2);
+
+        Plugin plugin = new Plugin();
+        Exception cause = new PluginContainerException(plugin, null, null, cause2);
+        cause2.initCause(cause);
+        PluginDescriptor pluginDescriptor = new PluginDescriptor();
+        MojoDescriptor mojoDescriptor = new MojoDescriptor();
+        mojoDescriptor.setPluginDescriptor(pluginDescriptor);
+        MojoExecution mojoExecution = new MojoExecution(mojoDescriptor);
+        Throwable exception = new PluginExecutionException(mojoExecution, null, cause);
+
+        DefaultExceptionHandler handler = new DefaultExceptionHandler();
+        ExceptionSummary summary = handler.handleException(exception);
+
+        String expectedReference = "http://cwiki.apache.org/confluence/display/MAVEN/PluginContainerException";
+        assertEquals(expectedReference, summary.getReference());
+    }
 }
diff --git a/maven-embedder/src/main/java/org/apache/maven/cli/CLIReportingUtils.java b/maven-embedder/src/main/java/org/apache/maven/cli/CLIReportingUtils.java
@@ -144,7 +144,9 @@ public static void showError(Logger logger, String message, Throwable e, boolean
             if (e != null) {
                 logger.error(e.getMessage());
 
-                for (Throwable cause = e.getCause(); cause != null; cause = cause.getCause()) {
+                for (Throwable cause = e.getCause();
+                        cause != null && cause != cause.getCause();
+                        cause = cause.getCause()) {
                     logger.error("Caused by: {}", cause.getMessage());
                 }
             }

diff --git a/maven-slf4j-provider/src/main/java/org/slf4j/impl/MavenSimpleLogger.java b/maven-slf4j-provider/src/main/java/org/slf4j/impl/MavenSimpleLogger.java
@@ -78,7 +78,7 @@ private void printStackTrace(Throwable t, PrintStream stream, String prefix) {
             writeThrowable(se, stream, "Suppressed", prefix + "    ");
         }
         Throwable cause = t.getCause();
-        if (cause != null) {
+        if (cause != null && t != cause) {
             writeThrowable(cause, stream, "Caused by", prefix);
         }
     }