Mathias Fußenegger created FLINK-24702: ------------------------------------------
Summary: toUpperCase/toLowerCase calls may cause problems with some system locales Key: FLINK-24702 URL: https://issues.apache.org/jira/browse/FLINK-24702 Project: Flink Issue Type: Technical Debt Reporter: Mathias Fußenegger I'm currently exploring the code base and saw several toUpperCase & toLowerCase calls on strings without explicitly declaring the Locale. This means it will use the System Locale which can lead to surprising behaviors, see [https://bugs.java.com/bugdatabase/view_bug.do?bug_id=6208680] > String.toLowerCase or String.toUpperCase sometimes fails to work when run in >a Turkish or Azeri environment [...]The reason is that Turkish and Azeri have >dotted and dotless "i"s, and conversion of these characters leads to results >that aren't adequate for strings in other languages I didn't investigate whether the current calls are actually problematic, but there could be bugs if there is a .equals() check following a toUpperCase/toLowerCase or when these strings are used in map lookups, etc. Projects like Lucene use [https://github.com/policeman-tools/forbidden-apis] to prevent this methods from being used to avoid these potential problems. -- This message was sent by Atlassian Jira (v8.3.4#803005)