[jira] [Commented] (LOG4J2-1216) Nested pattern layout options broken

["Barna Zsombor Klara (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/LOG4J2-1216?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16182311#comment-16182311 ] 

Barna Zsombor Klara commented on LOG4J2-1216:
---------------------------------------------

I think I ran into this issue recently and it seem it is still broken in 2.9.2-SNAPSHOT.
I tried the following patterns:
{code}
%notEmpty{%X{var}} - %maxLen{%X{var}}{2} -  %notEmpty{ %maxLen{%X{var}} }
{code}
and my output was:
{code}
2017-09-27 12:03:45,684 main ERROR Incorrect number of options on maxLength: expected 2 received 0: []
2017-09-27 12:03:45,687 main ERROR Unrecognized conversion specifier [maxLen] starting at position 16 in conversion pattern.
value - va -   }
{code}
The patterns work individually, but not when they are nested.

If I take a look at the unit test does your offer to merge it still stand [~jvz]?

> Nested pattern layout options broken
> ------------------------------------
>
>                 Key: LOG4J2-1216
>                 URL: https://issues.apache.org/jira/browse/LOG4J2-1216
>             Project: Log4j 2
>          Issue Type: Bug
>          Components: Pattern Converters
>    Affects Versions: 2.4.1
>            Reporter: Thies Wellpott
>              Labels: easyfix
>
> Parsing the "deeply" nested PatternLayout
> {code}
> %maxLen{[XXX, ${hostName}, ${web:contextPath}] %p: %c{1} - %m%notEmpty{ =>%ex{short}}}{160}
> {code}
> (with %maxLen being a custom Converter)
> results in wrong parsing.
> Patternparser.extractOptions() gets the nesting wrong.
> Solution:
> {code}
> private static int extractOptions(final String pattern, final int start, final List<String> options) {
>     int i = start;
>     while (i < pattern.length()  &&  pattern.charAt(i) == '{') {
>         i++;                      // skip opening "{"
>         final int begin = i;      // position of first real char
>         int depth = 1;            // already inside one level
>         while (depth > 0  &&  i < pattern.length()) {
>             char c = pattern.charAt(i);
>             if (c == '{') {
>                 depth++;
>             } else if (c == '}') {
>                 depth--;
>             // TODO(?) maybe escaping of { and } with \ or %
>             }
>             i++;
>         } // while
>         if (depth > 0) {          // option not closed, continue with pattern on opening "{"
>             return begin-1;
>         }
>         options.add(pattern.substring(begin, i-1));
>     } // while
>     return i;
> }
> {code}
> This should also be faster than the current implementation because the pattern ist only walked once, not multiple times with indexOf().
> (LOG4J2-107 is a similar but old bug)



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