Merge pull request #2808 from seregamorph/GITHUB-2807

GITHUB-2807 - Failsafe buildStackTrace

CHANGES.txt

@@ -2,6 +2,7 @@ Current
 New: Ability to provide custom error message for assertThrows\expectThrows methods (Anatolii Yuzhakov)
 Fixed: GITHUB-2780: Use SpotBugs instead of abandoned FindBugs
 Fixed: GITHUB-2801: JUnitReportReporter is too slow
+Fixed: GITHUB-2807: buildStackTrace should be fail-safe
 
 7.6.1
 Fixed: GITHUB-2761: Exception: ERROR java.nio.file.NoSuchFileException: /tmp/testngXmlPathInJar-15086412835569336174 (Krishnan Mahadevan)

testng-core-api/src/main/java/org/testng/internal/Utils.java

@@ -333,7 +333,13 @@ public static String shortStackTrace(Throwable t, boolean toHtml) {
   private static String buildStackTrace(Throwable t, boolean toHtml, StackTraceType type) {
     StringWriter sw = new StringWriter();
     PrintWriter pw = new PrintWriter(sw);
-    t.printStackTrace(pw);
+    try {
+      t.printStackTrace(pw);
+    } catch (Throwable e) {
+      // failsafe in case if printStackTrace throws exception
+      pw.println(t.getClass().getName());
+      e.printStackTrace(pw);
+    }
     pw.flush();
     String stackTrace = sw.getBuffer().toString();
     if (type == StackTraceType.SHORT && !isTooVerbose()) {

testng-core/src/test/java/org/testng/internal/UtilsTest.java

@@ -2,6 +2,7 @@
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.testng.Assert.assertEquals;
 import static org.testng.internal.Utils.join;
 
@@ -41,4 +42,23 @@ public void createEmptyStringWhenJoiningEmptyListWithJoinStrings() {
     List<String> emptyList = emptyList();
     assertEquals("", Utils.join(emptyList, ","));
   }
+
+  @Test
+  public void buildStackTraceShouldBeFailsafe() {
+    // e.g. mocks of Exception classes may throw exception on exception.toString()
+    RuntimeException ex = new ThrowingException();
+    String stackTrace = Utils.longStackTrace(ex, true);
+
+    assertThat(stackTrace)
+        .contains("org.testng.internal.UtilsTest$ThrowingException")
+        .contains("java.lang.IllegalStateException: message not available");
+  }
+
+  // exception which cannot be printed
+  private static class ThrowingException extends RuntimeException {
+    @Override
+    public String getMessage() {
+      throw new IllegalStateException("message not available");
+    }
+  }
 }