Align nightly cassert with main: 17.11 / 18.6 / 19beta3, drop PG16

[ibrahim halatci (ihalatci)]

What

Realigns .github/workflows/nightly_cassert.yml with main. Its params job is meant to be a mirror of build_and_test.yml, but it had drifted in both directions:

• it still built PG16, which main no longer compiles against, and
• it was missing PG19, which main does test.

main's params job currently pins 17.11 / 18.6 / 19beta3 and declares no pg16_version at all.

Changes

Output	Before	After
pg_versions	16.13, 17.9, 18.3	17.11, 18.6, 19beta3
pg_upgrade_pairs	16→17, 17→18	17→18, 18→19, 17→19
citus_upgrade_pg	16.13, 17.9	17.11, 18.6

Plus the file header comment, which advertised PG 16/17/18 and referenced a pg19-support branch that no longer exists (PG19 landed in main). citus_old_version is untouched.

Why PG16 comes out

Citus main no longer compiles against PostgreSQL 16 — configure aborts with:

configure: error: Citus is not compatible with the detected PostgreSQL version 16.

Every PG16 job was therefore guaranteed to fail regardless of minor. In run 34182646836 (2026-09-08), all 14 PG16 jobs were red:

cassert PG16 - regress / isolation / columnar / tap / failure /
               generator / citus-upgrade / arbitrary-configs-0..5
cassert PG16-PG17 - pg-upgrade

That is categorically different from a normal cassert failure: it is a build that cannot start, so it drowns out the assert signal this nightly exists to surface.

Why PG19 goes in

main already runs PG19 (19beta3), so the nightly should too. Unlike PG16, PG19 does build, so any redness it produces is real assert signal — exactly what this workflow is for, per its own header note that runs are expected to be red as pre-existing asserts surface.

citus_upgrade_pg deliberately stays at 17 + 18, mirroring main's test-citus-upgrade matrix: the older Citus versions used by that suite do not run on PG19.

Verification

The three params outputs are JSON-in-YAML strings, so they were checked by parsing rather than by eye. A script YAML-loads this workflow and fetches build_and_test.yml from main, then asserts the nightly mirrors it:

• majors match main's pg*_version set exactly (17, 18, 19), and every full equals main's
• pg_upgrade_pairs equals main's test-pg-upgrade include set exactly (17→18, 18→19, 17→19), with each old_full/new_full resolved from main
• citus_upgrade_pg majors equal main's test-citus-upgrade matrix (17, 18)
• no 16 / 16.13 token remains anywhere in the file, and no stale pg19-support reference

Result: MIRRORS MAIN EXACTLY - ALL ASSERTIONS PASSED.

The PG builds are from source via pgenv (setup_cassert_pg), whose input is documented as accepting betas (e.g. 17.10 / 18.4 / 19beta1). The 19beta3 source tarball is published (postgresql-19beta3.tar.bz2, HTTP 200), so the build is viable.

Notes

Companion to citus#8816 (nightly_arm64.yml). If that workflow has the same PG16/PG19 drift, it is best fixed there.

Refs citus#8804.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.72%. Comparing base (4ae7278) to head (aa7f469).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8822      +/-   ##
==========================================
- Coverage   88.73%   88.72%   -0.01%     
==========================================
  Files         289      289              
  Lines       65013    65013              
  Branches     8204     8204              
==========================================
- Hits        57687    57686       -1     
+ Misses       4957     4956       -1     
- Partials     2369     2371       +2     

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