connect() doesnt set errstr when the DB driver is missing

[rwfranks]

Transcribed verbatim from CPAN RT#127545, warts and all.

Thu Nov 01 14:15:30 2018 marshall.mills [...] gmail.com - Ticket created
Subject: connect() doesnt set errstr when the DB driver is missing

Date: Thu, 1 Nov 2018 18:15:19 +0000
To: [email protected]
From: Marshall Mills [email protected]

Hey everyone,

DBI->connect() doesn't set $DBI::errstr, at least when the DB driver is missing.

This cost me some time tracing down what I thought was a firewall
issue. But, it just turned out that the mysql driver was missing.

Linux 4.1.12-103.7.3.el7uek.x86_64
Perl v5.16.3

Expected output:

DBI::VERSION 1.642
DBI::errstr:  install_driver(uninstalledDriver) failed: Can't locate
DBD/uninstalledDriver.pm in @INC
Failed to correctly connect to the `example` database.

Actual output:

DBI::VERSION 1.642
Failed to correctly connect to the `example` database.

Thank you for your time,
Marshall

------------------------------------------------------------------------------------------
#!/usr/bin/perl

use strict;
use warnings;

use DBI;

print( "DBI::VERSION " . $DBI::VERSION  . "\n" );

my $databaseName = 'example';
my $server = 'data.example.com';
my $userName = 'admin';
my $password = 'Example code, please dont judge';

my $dataSource = "DBI:uninstalledDriver:database=$databaseName;host=$server";

my $dbConnection = undef;

# https://metacpan.org/pod/DBI#connect
# DBI->connect will die on a driver installation failure and will only
return undef on a connect failure,
# in which case $DBI::errstr will hold the error message. Use eval if
you need to catch the "install_driver" error.

eval
{
   $dbConnection = DBI->connect( $dataSource, $userName, $password,
{RaiseError=>1} );
};


if (defined( $DBI::errstr ))
{
   print( "DBI::errstr:  " . $DBI::errstr . "\n" );
}

if (!defined( $dbConnection ))
{
   print( "Failed to correctly connect to the `$databaseName` database.\n" );
   exit 1;
}

if (defined( $dbConnection ))
{
   $dbConnection->disconnect() || warn $dbConnection->errstr();
}

exit 0;