[LUCENE-10430] Literal double quotes cause exception in class RegExp

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 9.0
• Component/s: core/other
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Holger Rehn
• Created: 21/Feb/22 20:36
• Updated: 28/Aug/22 16:36
• Resolved: 26/Feb/22 21:52

Description

Class org.apache.lucene.util.automaton.RegExp fails to parse valid regular expressions that contain double quotes (except in character classes). This of course affects corresponding RegexpQuerys, as well.

Example: 

Query  q = new RegexpQuery( new Term( "field", "a\"b" ) );
RegExp r = new RegExp( "a\"b" );

Both fail with:

java.lang.IllegalArgumentException: expected '"' at position 3
    at org.apache.lucene.util.automaton.RegExp.parseSimpleExp(RegExp.java:1299)
    at org.apache.lucene.util.automaton.RegExp.parseCharClassExp(RegExp.java:1229)
    at org.apache.lucene.util.automaton.RegExp.parseComplExp(RegExp.java:1218)
    at org.apache.lucene.util.automaton.RegExp.parseRepeatExp(RegExp.java:1192)
    at org.apache.lucene.util.automaton.RegExp.parseConcatExp(RegExp.java:1185)
    at org.apache.lucene.util.automaton.RegExp.parseConcatExp(RegExp.java:1187)
    at org.apache.lucene.util.automaton.RegExp.parseInterExp(RegExp.java:1179)
    at org.apache.lucene.util.automaton.RegExp.parseUnionExp(RegExp.java:1173)
    at org.apache.lucene.util.automaton.RegExp.<init>(RegExp.java:496)
    ...

As a workaround we currently replace all double quotes with a dot.