[GitHub] nifi issue #3200: NIFI-5826 Fix back-slash escaping at Lexers

[ijokarumawak <gi...@git.apache.org>]

Github user ijokarumawak commented on the issue:

    https://github.com/apache/nifi/pull/3200
  
    @bdesert @ottobackwards Thanks for reviewing. I've added unit tests.
    
    As a reference, I run the added tests with Lexer before this PR. Following tests failed with current Lexer, but passes with the updated Lexer:
    
    This test failed with original Lexer because `[\s]` is converted to `[\\s]` by Lexer and didn't match.
    ```
    [ERROR] testReplaceRegexEscapedCharacters(org.apache.nifi.record.path.TestRecordPath)  Time elapsed: 0.007 s  <<< FAILURE!
    org.junit.ComparisonFailure:
    Replacing whitespace to new line expected:<John[
    ]Doe> but was:<John[ ]Doe>
            at org.apache.nifi.record.path.TestRecordPath.testReplaceRegexEscapedCharacters(TestRecordPath.java:1046)
    ```
    
    This test failed with original Lexer because `\[` is converted to `\\[` by Lexer and produced RegEx syntax error.
    ```
    [ERROR] testReplaceRegexEscapedBrackets(org.apache.nifi.record.path.TestRecordPath)  Time elapsed: 0.001 s  <<< ERROR!
    org.apache.nifi.record.path.exception.RecordPathException:
    java.util.regex.PatternSyntaxException: Unclosed character class near index 2
    \\[
      ^
            at org.apache.nifi.record.path.TestRecordPath.testReplaceRegexEscapedBrackets(TestRecordPath.java:1149)
    ```
    
    Both tests failed with the same cause, and fixed by this PR.


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