Re: BUG #18510: jsonpath does not support trailing backslash at the end of the query

On Fri, Jun 14, 2024 at 1:24 PM PG Bug reporting form <noreply@postgresql.org> wrote:

The following bug has been logged on the website:

Bug reference:      18510
Logged by:          Lex Vorona
Email address:      voronaam@gmail.com
PostgreSQL version: 16.3
Operating system:   Linux (Ubuntu)
Description:       

postgres=# select '$.field ? (@ like_regex "a\\")'::jsonpath; -- does not
work
ERROR:  invalid regular expression: invalid escape \ sequence
LINE 1: select '$.field ? (@ like_regex "a\\")'::jsonpath;

It is working just fine.  It sees both the regex and the backslash character and then helpfully tells you that the regex you wrote is bogus since the backslash you wrote isn't escaping anything.

If you need a literal backslash in a jsonpath string literal you need to write four of them.  Each pair leaves one \ in the regex and then \\ in a regex is just a literally matched character.

David J.