[yahonda]

Motivation

PostgreSQL-19 forces standard_conforming_strings to always be on and removes escape_string_warning.
Running the specs against a PostgreSQL-19 server, the embed_params specs fail because with_std_conf_strings switches these settings:

SET standard_conforming_strings = off
ERROR:  non-standard string literals are not supported

SET escape_string_warning = off
ERROR:  unrecognized configuration parameter "escape_string_warning"

The "on" variants fail too, since they also SET escape_string_warning = on.

• https://www.postgresql.org/docs/19/release-19.html#RELEASE-19-MIGRATION
• postgres/postgres@4576208

Changes

with_std_conf_strings checks conn.server_version. On PostgreSQL-19 and later it skips the "off" variants and runs the "on" variants without changing any settings. Older servers keep the current behavior.

How this was tested

CI does not run against PostgreSQL-19 yet. I tested this with PostgreSQL 19rc1 by adding it to the source-gem.yml matrix (not included in this pull request):

--- a/.github/workflows/source-gem.yml
+++ b/.github/workflows/source-gem.yml
@@ -57,6 +57,9 @@ jobs:
           - os: ubuntu
             ruby: "head"
             PGVER: "18"
+          - os: ubuntu
+            ruby: "head"
+            PGVER: "19"
           - os: ubuntu
             ruby: "3.3"
             PGVER: "12"

All jobs passed, and the PostgreSQL-19 job reports 1159 examples, 0 failures, with the 4 "off" variants pending: https://github.com/yahonda/ruby-pg/actions/runs/39204891098

[larskanis]

Thank you very much! I already noticed this change, but didn't take an action so far.