Re: strReplace -> j.u.regex.PatternSyntaxException should throw a ExprEvalException instead

[ajs6f]

Jerven, thanks for a good bug report (and double-thanks for accompanying it 
with a PR fix!).

Jena is as strong as we make it together.


ajs6f

Jerven Tjalling Bolleman wrote on 10/23/17 2:40 PM:

Dear Andy and all other Jena developers,

Thank you for taking and improving the patch!
As well as all your excellent work over the years.

Regards,
Jerven

On 10/23/2017 12:23 PM, Andy Seaborne wrote:

 > Does that seem sensible?

Yes - recorded as JENA-1403.

The static compilation case (the constructor E_strReplase) should also throw a 
ExprException.

     Thanks
     Andy

https://issues.apache.org/jira/browse/JENA-1403

On 23/10/17 09:23, Jerven Tjalling Bolleman wrote:

Dear Jena Developers,

I am doing some strange stuff with building regexes from data inside a sparql 
store. Sometimes that leads to invalid
regexes which ends up throwing PatternSyntaxExceptions.

For my use case it is fine that these would not evaluate properly. I believe 
however that the specific exception
about pattern syntax should be caught and turned into a ExprEvalException so 
that evaluation of queries can continue.

i.e. the following stacktrace (against jena 3.4.0) should be caught and not 
propegated.

java.util.regex.PatternSyntaxException: Illegal repetition near index 10
^(?:-*[^-]){-9}
           ^
         at java.util.regex.Pattern.error(Pattern.java:1955)
         at java.util.regex.Pattern.closure(Pattern.java:3157)
         at java.util.regex.Pattern.group0(Pattern.java:2912)
         at java.util.regex.Pattern.sequence(Pattern.java:2051)
         at java.util.regex.Pattern.expr(Pattern.java:1996)
         at java.util.regex.Pattern.compile(Pattern.java:1696)
         at java.util.regex.Pattern.<init>(Pattern.java:1351)
         at java.util.regex.Pattern.compile(Pattern.java:1054)
         at 
org.apache.jena.sparql.expr.nodevalue.XSDFuncOp.strReplace(XSDFuncOp.java:474)
         at 
org.apache.jena.sparql.expr.nodevalue.XSDFuncOp.strReplace(XSDFuncOp.java:518)


I suggest modifying the function

public static NodeValue strReplace(NodeValue nvStr, NodeValue nvPattern, 
NodeValue nvReplacement, NodeValue nvFlags) {
         String pat = checkAndGetStringLiteral("replace", 
nvPattern).getLiteralLexicalForm() ;
         int flags = 0 ;
         if ( nvFlags != null ) {
             String flagsStr = checkAndGetStringLiteral("replace", 
nvFlags).getLiteralLexicalForm() ;
             flags = RegexJava.makeMask(flagsStr) ;
         }
         return strReplace(nvStr, Pattern.compile(pat, flags), nvReplacement) ;
}

to be something like

public static NodeValue strReplace(NodeValue nvStr, NodeValue nvPattern, 
NodeValue nvReplacement, NodeValue nvFlags) {
         String pat = checkAndGetStringLiteral("replace", 
nvPattern).getLiteralLexicalForm() ;
         int flags = 0 ;
         if ( nvFlags != null ) {
             String flagsStr = checkAndGetStringLiteral("replace", 
nvFlags).getLiteralLexicalForm() ;
             flags = RegexJava.makeMask(flagsStr) ;
         }
         try {
             return strReplace(nvStr, Pattern.compile(pat, flags), 
nvReplacement) ;
     } catch (PatternSyntaxException ex){
         throw new ExprEvalException("PatternSyntaxException", ex) ;
         }
}

Does that seem sensible?

Regards,
Jerven