Thread: pgsql: Fix thinko coming from 000f3adf

Fix thinko coming from 000f3adf

pg_basebackup.c relies on the compression level to not be 0 to decide if
compression should be used, but 000f3adf missed the fact that the
default compression (Z_DEFAULT_COMPRESSION) is -1, which would be used
if specifying --gzip without --compress.

While on it, add some coverage for --gzip, as this is rather easy to
miss.

Reported-by: Christoph Berg
Discussion: https://postgr.es/m/YdhRDMLjabtXOnhY@msg.df7cb.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d0d62262d34154965511cfda6b98609d27752d5a

Modified Files
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src/bin/pg_basebackup/pg_basebackup.c        |  2 +-
src/bin/pg_basebackup/t/010_pg_basebackup.pl | 21 +++++++++++++++++----
2 files changed, 18 insertions(+), 5 deletions(-)