Re: Code review request for 8012044: Give more information about self-suppression from Throwable.addSuppressed

[Joe Darcy]

On 04/12/2013 07:29 PM, Jason Mehrens wrote:
Joe,
You'll have guard ise.addSuppressed against null.  Looks good otherwise.
private static void initCauseNull() {
      Throwable t1 = new Throwable();
      t1.initCause(null);
      try {
        t1.initCause(null);
      } catch(IllegalStateException expect) {
      }
}

Right you are; check added and test updated in:

    http://cr.openjdk.java.net/~darcy/8012044.2/

Full patch to Throwable:

--- old/src/share/classes/java/lang/Throwable.java    2013-04-14 
19:33:23.000000000 -0700
+++ new/src/share/classes/java/lang/Throwable.java    2013-04-14 
19:33:23.000000000 -0700
@@ -452,10 +452,15 @@
      * @since  1.4
      */
     public synchronized Throwable initCause(Throwable cause) {
-        if (this.cause != this)
-            throw new IllegalStateException("Can't overwrite cause");
+        if (this.cause != this) {
+            IllegalStateException ise =
+                new IllegalStateException("Can't overwrite cause", this);
+            if (cause != null)
+                ise.addSuppressed(cause);
+            throw ise;
+        }
         if (cause == this)
-            throw new IllegalArgumentException("Self-causation not 
permitted");
+            throw new IllegalArgumentException("Self-causation not 
permitted", this);
         this.cause = cause;
         return this;
     }
@@ -1039,7 +1044,7 @@
      */
     public final synchronized void addSuppressed(Throwable exception) {
         if (exception == this)
-            throw new IllegalArgumentException(SELF_SUPPRESSION_MESSAGE);
+            throw new 
IllegalArgumentException(SELF_SUPPRESSION_MESSAGE, exception);

         if (exception == null)
             throw new NullPointerException(NULL_CAUSE_MESSAGE);

Cheers,

-Joe

Jason
  
Date: Fri, 12 Apr 2013 12:08:07 -0700
From: joe.da...@oracle.com
To: jason_mehr...@hotmail.com
CC: core-libs-dev@openjdk.java.net
Subject: Re: Code review request for 8012044: Give more information about 
self-suppression from Throwable.addSuppressed
On 04/12/2013 11:22 AM, Jason Mehrens wrote:

The landmines are the retrofitted exception classes as shown here 
https://netbeans.org/bugzilla/show_bug.cgi?id=150969 and 
https://issues.jboss.org/browse/JBREM-552. Really, if the ISE or IAE is thrown 
it is going to suppress 'this' and 'cause'. It would be nice to see the given 
'cause' show up in a log file when tracking down this type of bug.
Okay; fair enough. Updated webrev covering initCause too at
  http://cr.openjdk.java.net/~darcy/8012044.1/
  New patch below.
  (It is a bit of stretch to have this in initiCause by listed as the "cause" 
of the IllegalStateException; as an alternative, the IllegalStateException could have 
both this and the cause as suppressed exceptions.)
  Cheers,
  -Joe
  --- old/src/share/classes/java/lang/Throwable.java 2013-04-12 
12:03:48.000000000 -0700
  +++ new/src/share/classes/java/lang/Throwable.java 2013-04-12 
12:03:48.000000000 -0700
  @@ -452,10 +452,14 @@
  * @since 1.4
  */
  public synchronized Throwable initCause(Throwable cause) {
  - if (this.cause != this)
  - throw new IllegalStateException("Can't overwrite cause");
  + if (this.cause != this) {
  + IllegalStateException ise =
  + new IllegalStateException("Can't overwrite cause", this);
  + ise.addSuppressed(cause);
  + throw ise;
  + }
  if (cause == this)
  - throw new IllegalArgumentException("Self-causation not permitted");
  + throw new IllegalArgumentException("Self-causation not permitted", this);
  this.cause = cause;
  return this;
  }
  @@ -1039,7 +1043,7 @@
  */
  public final synchronized void addSuppressed(Throwable exception) {
  if (exception == this)
  - throw new IllegalArgumentException(SELF_SUPPRESSION_MESSAGE);
  + throw new IllegalArgumentException(SELF_SUPPRESSION_MESSAGE, exception);
  if (exception == null)
  throw new NullPointerException(NULL_CAUSE_MESSAGE);
  --- old/test/java/lang/Throwable/SuppressedExceptions.java 2013-04-12 
12:03:49.000000000 -0700
  +++ new/test/java/lang/Throwable/SuppressedExceptions.java 2013-04-12 
12:03:48.000000000 -0700
  @@ -26,7 +26,7 @@
  /*
  * @test
  - * @bug 6911258 6962571 6963622 6991528 7005628
  + * @bug 6911258 6962571 6963622 6991528 7005628 8012044
  * @summary Basic tests of suppressed exceptions
  * @author Joseph D. Darcy
  */
  @@ -40,6 +40,7 @@
  serializationTest();
  selfReference();
  noModification();
  + initCausePlumbing();
  }
  private static void noSelfSuppression() {
  @@ -48,7 +49,9 @@
  throwable.addSuppressed(throwable);
  throw new RuntimeException("IllegalArgumentException for self-suppresion not 
thrown.");
  } catch (IllegalArgumentException iae) {
  - ; // Expected
  + // Expected to be here
  + if (iae.getCause() != throwable)
  + throw new RuntimeException("Bad cause after self-suppresion.");
  }
  }
  @@ -208,4 +211,29 @@
  super("The medium.", null, enableSuppression, true);
  }
  }
  +
  + private static void initCausePlumbing() {
  + Throwable t1 = new Throwable();
  + Throwable t2 = new Throwable("message", t1);
  + Throwable t3 = new Throwable();
  +
  + try {
  + t2.initCause(t3);
  + throw new RuntimeException("Shouldn't reach.");
  + } catch (IllegalStateException ise) {
  + if (ise.getCause() != t2)
  + throw new RuntimeException("Unexpected cause in ISE", ise);
  + Throwable[] suppressed = ise.getSuppressed();
  + if (suppressed.length != 1 || suppressed[0] != t3)
  + throw new RuntimeException("Bad suppression in ISE", ise);
  + }
  +
  + try {
  + t3.initCause(t3);
  + throw new RuntimeException("Shouldn't reach.");
  + } catch (IllegalArgumentException iae) {
  + if (iae.getCause() != t3)
  + throw new RuntimeException("Unexpected cause in ISE", iae);
  + }
  + }
  }