BUG #18095: Unintended non-SSL connection attempt by psql cli command after a failed password authentication

The following bug has been logged on the website:

Bug reference: 18095
Logged by: Youssef TOURKI
Email address: ytourki(at)ext(dot)scaleway(dot)com
PostgreSQL version: 14.9
Operating system: Ubuntu 22
Description:

The bug is related to the psql client (cli)

When connecting to a PostgreSQL server (version 14) configured to only
accept SSL connections, if a user provides an incorrect password, the psql
client (version 14) returns two error messages in succession. The first
message correctly indicates a password authentication failure, but the
second suggests an unexpected non-SSL connection attempt.

Steps to Reproduce:

Configure the PostgreSQL server to accept only SSL connections.
Use the psql client to connect to the server, intentionally providing an
incorrect password.
Observe the error messages returned.
Expected Behavior:

Upon providing an incorrect password, the user should receive a single error
message related to the authentication failure. The client should not attempt
a non-SSL connection, especially given that the server is configured to only
accept SSL.

Actual Behavior:

Two error messages are displayed in the following order:

psql: error: connection to server at "172.17.0.4", port 5432 failed: FATAL:
password authentication failed for user "postgres"
connection to server at "172.17.0.4", port 5432 failed: FATAL: no
pg_hba.conf entry for host "172.17.0.1", user "postgres", database
"postgres", no encryption

The second message indicates an unexpected non-SSL connection attempt by the
psql client after the initial authentication failure.

Environment:

PostgreSQL Server Version: 14
psql Client Version: 14