Skip to content

[DOCS] Clarify regex character range case insensitivity limitations #125412

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Mar 21, 2025
Merged

[DOCS] Clarify regex character range case insensitivity limitations #125412

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 9 additions & 0 deletions docs/reference/query-dsl/regexp-syntax.asciidoc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -181,6 +181,15 @@ example:
[^-abc] # matches any character except '-', 'a', 'b', or 'c'
[^abc\-] # matches any character except 'a', 'b', 'c', or '-'
....

[NOTE]
====
Character range classes such as `[a-c]` do not behave as expected when using `case_insensitive: true` — they remain case sensitive.
For example, `[a-c]+` with `case_insensitive: true` will match strings containing only the characters 'a', 'b', and 'c', but not 'A', 'B', or 'C'.
Use `[a-zA-Z]` to match both uppercase and lowercase characters.
This is due to a known limitation in Lucene's regular expression engine.
See https://github.com/apache/lucene/issues/14378[Lucene issue #14378] for details.
====
--

[discrete]
Expand Down