[NIFI-3837] ReplaceText - Backreference escape issue in Regex Replace mode when using EL

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.3.0
• Component/s: Extensions
• Assignee: Matt Gilman
• Reporter: Matt Gilman
• Created: 08/May/17 16:37
• Updated: 12/May/17 02:38
• Resolved: 12/May/17 02:38

Description

When using ReplaceText in Regex Replace mode, $'s may be incorrectly interrupted as a backreference and escaped. Given input

'ma$tt'

and the following ReplaceText configuration:

Search Value - (?s)(^.*$)
Replacement Value - ${'$1'}
Character Set - UTF-8
Maximum Buffer Size - 1 MB
Replacement Strategy - Regex Replace
Evaluation Mode - Entire text

The resulting output is

'ma\$tt'

The issue appears to be that this regular expression is too general [1]. This happens when the replacement string uses expression language. It appears as though all backreferences will be escaped.

[1] https://github.com/apache/nifi/blob/master/nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/ReplaceText.java#L500

Issue Links

• links to: GitHub Pull Request #1781