Improve guards against false regex matches in BackgroundPsql.pm. BackgroundPsql needs to wait for all the output from an interactive psql command to come back. To make sure that's happened, it issues the command, then issues \echo and \warn psql commands that echo a "banner" string (which we assume won't appear in the command's output), then waits for the banner strings to appear. The hazard in this approach is that the banner will also appear in the echoed psql commands themselves, so we need to distinguish those echoes from the desired output. Commit 8b886a4e3 tried to do that by positing that the desired output would be directly preceded and followed by newlines, but it turns out that that assumption is timing-sensitive. In particular, it tends to fail in builds made --without-readline, wherein the command echoes will be made by the pty driver and may be interspersed with prompts issued by psql proper.
It does seem safe to assume that the banner output we want will be followed by a newline, since that should be the last output before things quiesce. Therefore, we can improve matters by putting quotes around the banner strings in the \echo and \warn psql commands, so that their echoes cannot include banner directly followed by newline, and then checking for just banner-and-newline in the match pattern. While at it, spruce up the pump() call in sub query() to look like the neater version in wait_connect(), and don't die on timeout until after printing whatever we got. Reported-by: Oleg Tselebrovskiy <[email protected]> Diagnosed-by: Oleg Tselebrovskiy <[email protected]> Author: Tom Lane <[email protected]> Reviewed-by: Soumya S Murali <[email protected]> Discussion: https://postgr.es/m/[email protected] Backpatch-through: 14 Branch ------ REL_14_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/fc84b3977e20bc6ca7db349401d7f8ad02a90d82 Modified Files -------------- src/test/perl/PostgreSQL/Test/BackgroundPsql.pm | 40 ++++++++++++------------- 1 file changed, 19 insertions(+), 21 deletions(-)
