Fixing JDK-8130493

Jan Lahoda jan.lahoda at oracle.com
Wed Jan 10 20:25:18 UTC 2018 

On 10.1.2018 20:06, Jonathan Gibbons wrote:
> Jan,
>
> javac should not generate a stacktrace in this situation. This case is
> about a bad class file, and so javac should generate an informative
> message, in the family of "bad class file" or "class not found" messages.
>
> javac should only resort to stacktraces when code has crashed or
> otherwise behaved unexpectedly, such that javac cannot provide a helpful
> message.  There are two sub-cases here ... the crash is in javac code or
> libraries that it might call, in which case the message is, "oops, our
> fault, please report a bug", or the crash is in user code, in which
> case, the message is effectively, "it's your problem , not javac"

(Especially for the exception from JDK-8130493.) I think this case is 
close to the "it's your problem , not javac" - the problem happens when 
the ServiceLoader tries to load a user's class into the VM (putting 
aside that it wasn't wrapped in the ServiceConfigurationError, as I'd 
expect based on the ServiceLoader javadoc) and it fails. So, while the 
specific stacktrace in the bug does not seem particularly useful, in 
other cases the exception may be useful for the user to diagnose the 
problem. I'd assume that this situation is fairly rare, and so I 
personally wouldn't mind more detailed output that could help to 
determine what is the cause of the problem.

Jan

>
> -- Jon
>
> On 01/10/2018 09:41 AM, Jan Lahoda wrote:
>> For a minimal change, I think it should be enough to change (in
>> ServiceIterator) the existing:
>> ---
>>             } catch (Throwable t) {
>>                 throw new Abort(t);
>>             }
>> ---
>> to
>> ---
>>             } catch (Throwable t) {
>>                 throw new AnnotationProcessingError(t);
>>             }
>> ---
>>
>> AnnotationProcessingError is handled both in JavacTaskImpl and
>> com.sun.tools.javac.main.Main. For command line javac, this would get
>> an output like:
>> ---
>> An annotation processor threw an uncaught exception.
>> Consult the following stack trace for details.
>> java.lang.ClassFormatError: Truncated class file
>> [stacktrace]
>> ---
>>
>> Which is in line with the behavior when -processor <name> is used
>> (NameProcessIterator).
>>
>> But I guess it would be good to improve consistency of error handling
>> in JavacProcessingEnvironment at some point.
>>
>> Jan
>>
>> On 10.1.2018 18:23, Jonathan Gibbons wrote:
>>> Why would you not just change
>>>
>>>
>>> from
>>>
>>> } catch (Throwable t) {
>>>
>>> log.error("proc.service.problem");
>>>
>>> throw new Abort(t);
>>>
>>> to
>>>
>>> } catch (Throwable t) {
>>>
>>> log.error("proc.service.problem");
>>>
>>> throw new AnnotationProcessingError(t);
>>>
>>>
>>> and then briefly, concisely, handle AnnotationProcessingError in
>>> JavaCompiler.
>>>
>>> -- Jon
>>>
>>>
>>> On 1/10/18 9:13 AM, Schaef, Martin wrote:
>>>>
>>>> I understand. The bare minimum that fixes the test cases would be to
>>>> change the exception handling in the constructor of ServiceIterator:
>>>>
>>>> http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l340
>>>>
>>>>
>>>> and in ServiceIterator.next():
>>>>
>>>> http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l363
>>>>
>>>>
>>>> from
>>>>
>>>> } catch (Throwable t) {
>>>>
>>>> log.error("proc.service.problem");
>>>>
>>>> throw new Abort(t);
>>>>
>>>> to
>>>>
>>>> } catch (Exception t) {
>>>>
>>>> log.error("proc.service.problem");
>>>>
>>>> throw new Abort(t);
>>>>
>>>> } catch (Throwable t) {
>>>>
>>>> log.error("Some error text");
>>>>
>>>> throw new AnnotationProcessingError (t);
>>>>
>>>> With this change, the exit code of javac is 3 instead of 0.
>>>>
>>>> Does that sound like something you could support? If so, what should
>>>> go in the log.error messages?
>>>>
>>>> Cheers,
>>>>
>>>> Martin
>>>>
>>>> *From: *Jonathan Gibbons <jonathan.gibbons at oracle.com>
>>>> *Date: *Wednesday, January 10, 2018 at 11:39 AM
>>>> *To: *"Schaef, Martin" <schaef at amazon.com>,
>>>> "compiler-dev at openjdk.java.net" <compiler-dev at openjdk.java.net>
>>>> *Cc: *"Hohensee, Paul" <hohensee at amazon.com>
>>>> *Subject: *Re: Fixing JDK-8130493
>>>>
>>>> Martin,
>>>>
>>>> I have not read your patch, but changing the semantics of the iterator
>>>> sounds like a step too far.
>>>>
>>>> Without trying to implement the following yet, I would expect the
>>>> general direction of a solution to be to one of the following:
>>>>
>>>> 1. if the exception should be fatal, allow it to propagate up to
>>>> JavaCompiler, (similar to as now) but maybe with a custom new wrapper
>>>> exception
>>>>
>>>> 2. if the exception should not be fatal, translate it to an error
>>>> message (log.error(...)) and continue.
>>>>
>>>> It probably needs more analysis and discussion to determine which of
>>>> those two directions to take.
>>>>
>>>> -- Jon
>>>>
>>>> On 1/10/18 8:17 AM, Schaef, Martin wrote:
>>>>
>>>>     Let me revise that:
>>>>
>>>>     In JavacProcessingEnvironment.initProcessorIterator
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l256>
>>>>
>>>>     the code chooses one of two types of iterators:
>>>>
>>>>     The NameProcessIterator
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l384>
>>>>
>>>>     if ther -processor flag is given or the ServiceIterator
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l325>.
>>>>
>>>>
>>>>     If we look at the NameProcessIterator.hasNext()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l396>
>>>>
>>>>     implementation, it checks if there is a next name AND checks if
>>>>     this class name can be loaded. That is, if the class is not
>>>>     present, the hasNext() method already returns false (or, in our
>>>>     case, throws the NoClassDefFoundError which gets wrapped into an
>>>>     AnnotationProcessingError).
>>>>
>>>>     If we look at the ServiceIterator together with the stack trace
>>>>     from my previous email, we see that the .hasNext() and .next()
>>>>     calls get forwarded into the ServiceLoader.LazyIterator
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/util/ServiceLoader.java#l257>.
>>>>
>>>>     This behaves different than the NameProcessIterator: hasNext()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/util/ServiceLoader.java#l222>
>>>>
>>>>     only checks if a next name exists and would not throw a
>>>>     NoClassDefFoundError. Then next()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/util/ServiceLoader.java#l256>
>>>>
>>>>     throws the NoClassDefFoundError which gets caught by the catch-all
>>>>     in JavaProcessingEnvironment.ServiceIterator.next()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l363>
>>>>
>>>>     and wrapped into an Abort.
>>>>
>>>>     So, to summarize:
>>>>
>>>>     For a NameProcessIterator, a missing class causes a
>>>>     AnnotationProcessingError thrown from
>>>>     NameProcessIterator.hasNext()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l396>
>>>>
>>>>     and for ServiceIterator, it causes a Abert thrown by
>>>>     JavaProcessingEnvironment.ServiceIterator.next()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l363>.
>>>>
>>>>
>>>>     I could fix my problem and JDK-8130493
>>>>     <https://bugs.openjdk.java.net/browse/JDK-8130493> by checking if
>>>>     the class can be loaded in the hasNext method and changing the
>>>>     exception handling in
>>>>     JavaProcessingEnvironment.ServiceIterator.next()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l363>.
>>>>
>>>>     The problem with that is that the lazy iterator is not lazy
>>>>     anymore. Is there a reason why this Iterator has to be lazy?
>>>>
>>>>     I attached a patch that solves the issue for me. Feedback would be
>>>>     great.
>>>>
>>>>     Cheers,
>>>>
>>>>     Martin
>>>>
>>>>     *From: *compiler-dev <compiler-dev-bounces at openjdk.java.net>
>>>>     <mailto:compiler-dev-bounces at openjdk.java.net> on behalf of
>>>>     "Schaef, Martin" <schaef at amazon.com> <mailto:schaef at amazon.com>
>>>>     *Date: *Tuesday, January 9, 2018 at 3:37 PM
>>>>     *To: *Jonathan Gibbons <jonathan.gibbons at oracle.com>
>>>>     <mailto:jonathan.gibbons at oracle.com>,
>>>>     "compiler-dev at openjdk.java.net"
>>>>     <mailto:compiler-dev at openjdk.java.net>
>>>>     <compiler-dev at openjdk.java.net>
>>>> <mailto:compiler-dev at openjdk.java.net>
>>>>     *Subject: *Re: Fixing JDK-8130493
>>>>
>>>>     It’s a user class. See full stack trace below.
>>>>
>>>>     The problem is that the ClassNotFound is already caught at
>>>> com.sun.tools.javac.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:255)
>>>>
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/util/ServiceLoader.java#l257>
>>>>
>>>>     which already wraps it in a ServiceConfigurationError
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/util/ServiceLoader.java#l100>
>>>>
>>>>     in the fail method. That is, the exception gets wrapped twice.
>>>>     First, LazyIterator.next wraps it in a ServieConfigurationError,
>>>>     then ServiceIterator.next wraps it in an Abort.
>>>>
>>>>     Is it safe to change both wrappings?
>>>>
>>>>     com.sun.tools.javac.util.Abort: java.lang.NoClassDefFoundError:
>>>> com/amazon/coral/util/reflection/AnnotatedManifestAnnotationProcessor
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment$ServiceIterator.next(JavacProcessingEnvironment.java:364)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment$ServiceIterator.next(JavacProcessingEnvironment.java:325)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment$DiscoveredProcessors$ProcessorStateIterator.next(JavacProcessingEnvironment.java:597)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:690)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment.access$1800(JavacProcessingEnvironment.java:91)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1035)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1176)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1170)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:856)
>>>>
>>>>         at com.sun.tools.javac.main.Main.compile(Main.java:523)
>>>>
>>>>         at com.sun.tools.javac.main.Main.compile(Main.java:381)
>>>>
>>>>         at com.sun.tools.javac.main.Main.compile(Main.java:370)
>>>>
>>>>         at com.sun.tools.javac.main.Main.compile(Main.java:361)
>>>>
>>>>         at com.sun.tools.javac.Main.compile(Main.java:56)
>>>>
>>>>         at com.sun.tools.javac.Main.main(Main.java:42)
>>>>
>>>>     Caused by: java.lang.NoClassDefFoundError:
>>>> com/amazon/coral/util/reflection/AnnotatedManifestAnnotationProcessor
>>>>
>>>>         at java.lang.ClassLoader.defineClass1(Native Method)
>>>>
>>>>         at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
>>>>
>>>>         at
>>>> java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
>>>>
>>>>         at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
>>>>
>>>>         at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
>>>>
>>>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
>>>>
>>>>         at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
>>>>
>>>>         at java.security.AccessController.doPrivileged(Native Method)
>>>>
>>>>         at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
>>>>
>>>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
>>>>
>>>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
>>>>
>>>>         at java.lang.Class.forName0(Native Method)
>>>>
>>>>         at java.lang.Class.forName(Class.java:348)
>>>>
>>>>         at
>>>> com.sun.tools.javac.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:255)
>>>>
>>>>
>>>>         at
>>>> com.sun.tools.javac.util.ServiceLoader$1.next(ServiceLoader.java:337)
>>>>
>>>>         at
>>>> com.sun.tools.javac.processing.JavacProcessingEnvironment$ServiceIterator.next(JavacProcessingEnvironment.java:359)
>>>>
>>>>
>>>>         ... 14 more
>>>>
>>>>     Caused by: java.lang.ClassNotFoundException:
>>>> com.amazon.coral.util.reflection.AnnotatedManifestAnnotationProcessor
>>>>
>>>>         at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
>>>>
>>>>         at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
>>>>
>>>>        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
>>>>
>>>>     *From: *Jonathan Gibbons <jonathan.gibbons at oracle.com>
>>>>     <mailto:jonathan.gibbons at oracle.com>
>>>>     *Date: *Tuesday, January 9, 2018 at 1:19 PM
>>>>     *To: *"Schaef, Martin" <schaef at amazon.com>
>>>>     <mailto:schaef at amazon.com>, "compiler-dev at openjdk.java.net"
>>>>     <mailto:compiler-dev at openjdk.java.net>
>>>>     <compiler-dev at openjdk.java.net>
>>>> <mailto:compiler-dev at openjdk.java.net>
>>>>     *Subject: *Re: Fixing JDK-8130493
>>>>
>>>>     What is the class triggering the ClassNotFoundException?
>>>>
>>>>     If it is a user class not being found, it should be wrapped in a
>>>>     ClientCodeException.   If it is a javac class not being found, it
>>>>     is reasonable to wrap it in an Abort.
>>>>
>>>>     -- Jon
>>>>
>>>>     On 1/9/18 9:52 AM, Schaef, Martin wrote:
>>>>
>>>>         Hi,
>>>>
>>>>         We have some users suffering from JDK-8130493
>>>> <https://bugs.openjdk.java.net/browse/JDK-8130493> (their
>>>>         builds succeed, but the compiler actually failed). I did some
>>>>         digging and the following sequence happens:
>>>>
>>>>         A ClassNotFoundException is thrown in
>>>>         JavaProcessingEnvironment.ServiceIterator.next()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java#l364>
>>>>
>>>>         and re-thrown as an Abort.
>>>>
>>>>         This Abort reaches JavaCompiler.processAnnotations()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java#l1170>
>>>>
>>>>         and is finally caught in JavaCompiler.compile()
>>>> <http://hg.openjdk.java.net/jdk8u/jdk8u/langtools/file/989188d1a978/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java#l856>
>>>> by
>>>>         the following snippet:
>>>>
>>>>                 try {
>>>>
>>>>         initProcessAnnotations(processors);
>>>>
>>>>                     // These method calls must be chained to avoid
>>>>         memory leaks
>>>>
>>>>         delegateCompiler =
>>>>
>>>>         processAnnotations( //<<<<<< ABORT COMES OUT HERE
>>>>
>>>>         enterTrees(stopIfError(CompileState.PARSE,
>>>>         parseFiles(sourceFileObjects))),
>>>>
>>>>         classnames);
>>>>
>>>>         …
>>>>
>>>>                 } catch (Abort ex) {
>>>>
>>>>                     if (devVerbose)
>>>>
>>>>         ex.printStackTrace(System.err);
>>>>
>>>>                 } finally {
>>>>
>>>>         and swallowed ... but it's printed if XDev is set.
>>>>
>>>>         What is a proper way to fix this? Is it correct to wrap all
>>>>         exceptions in JavaProcessingEnvironmentServiceIterator into
>>>>         aborts? Or would it be better to distinguish different Aborts
>>>>         in JavaCompiler.java?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>

More information about the compiler-dev mailing list