postgres ensure socketDir mktemp init succeeds

[johnalotoski]

• Ensure postgres socketDir mktemp initialization succeeds when the socketDir path does not exist yet
  • See postgres: add socketDir option #77 (comment)
• Add a test for socketDir configured with a multi-level non-existing path

[shivaraj-bh]

Can we also add a test for the scenario where socketDir is different from dataDir? pg2 in nix/postgres/postgres_test can be used for this maybe? even pg1 works. Should’ve done this in the last PR perhaps, would’ve been caught in CI.

[johnalotoski]

Good idea, I can look at doing that tomorrow.

[johnalotoski]

Added the test @shivaraj-bh.

[shivaraj-bh]

Great!

Just to confirm I ran the test with the current main, and as expected it does fail:

Looks good