improved regex functionality and error handling
In context of conversations on POSIX regular expressions in YDB and YDBOcto projects, I have been experimenting with the current implementation a bit more and this is the outcome.
The main change is not to call
regexec if the
regcomp failed -- most likely due to an invalid regular expression. The new behaviour is that
regmatch returns number of matches rather than tfval. If the number of matches is <0, it is treated as an error. I didn't bother to implement
regerror at the moment.
A simple GitLabCI integration is also part of this PR but due to systemd/journald issue, one of the tests has been disabled exclusively for CI runs.