flake: TestServer/CanListenUnspecifiedv4

[blink-so]

Test failure seen in CI run: https://github.com/coder/coder/actions/runs/17274649293

Error:

=== FAIL: cli TestServer/CanListenUnspecifiedv4 (0.14s)
    clitest.go:267: command "coder server" exited with error: running command "coder server": connect to postgres:
            github.com/coder/coder/v2/cli.(*RootCmd).Server.func2
                /home/runner/work/coder/coder/cli/server.go:732
          - connect to postgres:
            github.com/coder/coder/v2/cli.getAndMigratePostgresDB
                /home/runner/work/coder/coder/cli/server.go:2788
          - get postgres version:
            github.com/coder/coder/v2/cli.ConnectToPostgres
                /home/runner/work/coder/coder/cli/server.go:2336
          - pq: canceling statement due to user request

Commit: 0b6f353b99d1e1f05707a82aee381c242aeb6522
Committer: jdomeracki-coder

This appears to be a PostgreSQL connection timeout/cancellation issue similar to other flakes we've seen with the same "pq: canceling statement due to user request" error.

[spikecurtis]

I'm pretty sure the problem here is that we are tearing down the test as soon as we see a specific log line in the server output. This causes cancelation of the command context, which then manifests as failing to connect to postgres and the server process returns a non-zero exit code.

[blink-so]

New occurrence on main.

CI run: https://github.com/coder/coder/actions/runs/17862044421
Job: test-go-pg (ubuntu-latest)

Error excerpt:

FAIL: cli TestServer/CanListenUnspecifiedv4 (0.11s)
clitest.go:267: command "coder server" exited with error: running command "coder server": connect to postgres:
  github.com/coder/coder/v2/cli.(*RootCmd).Server.func2 (/cli/server.go:743)
- connect to postgres:
  github.com/coder/coder/v2/cli.getAndMigratePostgresDB (/cli/server.go:2807)
- unable to connect after 1 tries; last error:
  github.com/coder/coder/v2/cli.ConnectToPostgres (/cli/server.go:2341)
- driver: bad connection

Classification: Infrastructure/DB flake (PostgreSQL connection issue). No data race, panic, or OOM indicators detected. Other matrix jobs were cancelled as a consequence of this failure.

[blink-so]

New Failure Occurrence

CI Run: https://github.com/coder/coder/actions/runs/17985135226
Job: test-go-pg-17
Commit: 2df9c5b6b5b06dcc1f738e6267188d8e0c74f219
Date: 2025-09-24 17:59:16 UTC

Error:

=== FAIL: cli TestServer/CanListenUnspecifiedv4 (0.22s)
    clitest.go:267: command "coder server" exited with error: running command "coder server": connect to postgres:
            github.com/coder/coder/v2/cli.(*RootCmd).Server.func2
                /home/runner/work/coder/coder/cli/server.go:743
          - connect to postgres:
            github.com/coder/coder/v2/cli.getAndMigratePostgresDB
                /home/runner/work/coder/coder/cli/server.go:2794
          - unable to connect after 1 tries; last error:
            github.com/coder/coder/v2/cli.ConnectToPostgres
                /home/runner/work/coder/coder/cli/server.go:2328
          - driver: bad connection

Analysis:
Same PostgreSQL connection issue as previous occurrences. The error "driver: bad connection" suggests the embedded PostgreSQL instance wasn't fully ready when the test tried to connect.

Assignment Rationale:
Keeping assigned to @spikecurtis as per previous occurrences of this flake.