Thread: pgsql: Reject missing database name in pg_regress and cohorts.

Reject missing database name in pg_regress and cohorts.

Writing "pg_regress --dbname= ..." led to a crash, because
we weren't expecting there to be no database name supplied.
It doesn't seem like a great idea to run regression tests
in whatever is the user's default database; so rather than
supporting this case let's explicitly reject it.

Per report from Xing Guo.  Back-patch to all supported
branches.

Discussion: https://postgr.es/m/CACpMh+A8cRvtvtOWVAZsCM1DU81GK4DL26R83y6ugZ1osV=ifA@mail.gmail.com

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/04f3acc97e426c5df1e31cd51b86fc1a93ca77dc

Modified Files
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src/test/regress/pg_regress.c | 11 +++++++++++
1 file changed, 11 insertions(+)