I'd like to propose a small enhancement to psql that improves usability when working with connection services and other libpq connection parameters.
Problem
Currently, when users try to use connection string parameters like service=myservice as positional arguments to psql, the behavior is confusing. For example:
This fails with: Password for user dbname=postgres: psql: error: password authentication failed for user "dbname=postgres"
The issue is that psql interprets service=centraldb as the database name (first positional arg) and dbname=postgres as the username (second positional arg), treating them as literal strings rather than connection parameters.
Use Case
This is particularly inconvenient when working with pg_service.conf, where users define connection profiles but occasionally need to override specific parameters. Currently, the workaround requires quoting the entire connection string:
The proposed syntax is more intuitive and aligns with how other tools handle similar parameter overrides.
Solution
This patch modifies psql to recognize positional arguments containing = as connection string parameters. These are collected into a connection string that serves as the base for the connection. Explicit options (-d, -h, -p, -U) override corresponding values.
The implementation: - Adds a connstring field to struct adhoc_opts - Modifies parse_psql_options() to detect and collect key=value arguments - Updates the connection logic to merge connstring with explicit options
Backward Compatibility
This change is fully backward compatible: - Regular positional arguments (without =) continue to work as database name and username - Database names containing = are rare and can still be specified via -d "db=name" - All existing command-line patterns remain functional
Examples
# Use service with database override psql service=production -d postgres
The patch includes a new TAP test file (t/002_connstring.pl) with 17 test cases covering: - Basic key=value positional arguments - Override behavior with -d flag - Multiple key=value parameters - Mixed key=value and regular positional arguments - Parameter ordering variations
