Parse error

[sergiob]

Hi,

I'm getting a parse exception with the following simple rule:

RULE test

CLASS my.class.name

METHOD method.name

AT ENTRY

DO NOTHING

ENDRULE

I enabled rule debugging and got the following:

    [junit] TransformListener() : handling connection on port 9091

    [junit] retransforming my.class.name

    [junit] org.jboss.byteman.agent.Transformer : error parsing rule test

    [junit] org.jboss.byteman.rule.exception.ParseException: rule test

    [junit] java.io.ByteArrayInputStream@283aa791 line 5 : unable to recover from previous errors

And:

    [junit] # Initializing parser

    [junit] # Current Symbol is #4

    [junit] # Attempting error recovery

    [junit] # Finding recovery state on stack

    [junit] # Pop stack by one, state was # 0

    [junit] # No recovery state found on stack

    [junit] # Error recovery fails

Which hardly makes sense to me, as line 5 is just "DO NOTHING", so what am I missing?

Thanks,

Sergio B.

[sergiob]

As an additional info, I tried debugging and verified the RuleScript object contains "DO NOTHING" in the rule text, as expected: then it gets passed to the ECAGrammarParser, and everything breaks as reported.

[sergiob]

Solved, the problem was the missing "catch all" condition (IF TRUE): I used Byteman long time ago and I was remembering it was not mandatory, but apparently I was wrong, or maybe things changed.

[adinn]

Hi Sergio,

Sergio Bossa wrote:

Solved, the problem was the missing "catch all" condition (IF TRUE): I used Byteman long time ago and I was remembering it was not mandatory, but apparently I was wrong, or maybe things changed.

The IF clause has always been mandatory.

I suppose we could relax that requirement but

1. it's hardly a big deal to have to type IF true (although you would be surprised how much it appears to annoy some people :-)
2. making it mandatory means you have to think about when you want the rule to fire and explicitly specify the 'always' case

The thing I should do  is to add this as an error pattern in the parser. So, when it sees a DO without an intervening IF it will recognise that the condition has been omitted and generate an error message to that effect. I'll raise a JIRA for this. Thanks for reporting your problem.

regards,

Andrew Dinn

[adinn]

Here's the JIRA

  https://issues.jboss.org/browse/BYTEMAN-247

[sergiob]

Hi Andrew,

thanks for your answer (and your great work on Byteman).

Good to know it has always been mandatory, my memory is definitely faulted, I should have re-read the manual

By the way, I'm absolutely fine with keeping it mandatory and having the parser emitting an error if missing.

Thanks again,

Regards,

Sergio B.