db2 driver does not support blank username and password for *LOCAL connections

[NattyNarwhal]

Description

A common idiom on IBM i is to use *LOCAL without a username and a password to establish a connection running with the same profile as the process. However, the ADOdb Db2 driver mandates that one must be set.

Environment

• ADOdb version: 5.22.7
• Driver or Module: Db2
• Database type and version: Db2
• PHP version: PHP 8.3.7
• Platform: IBM i 7.5

• I have tested that the problem is reproducible in the latest release / master branch / latest hotfix branch
  ⚠️ Keep only the applicable option(s), i.e. where you actually tested, and remove the others

Steps to reproduce

$adoDbDir = "vendor/adodb/adodb-php";
require "$adoDbDir/adodb.inc.php";

$db = newAdoConnection("db2");
var_dump($db->connect("*LOCAL", null, null));

$sql = "select * from qcustcdt";
$array = $db->getAll($sql);

print_r($array);

It doesn't seem to handle this very well, continuing on even though connect returned false and getting to a point where it uses false instead of the connection resource.

PHP Fatal error:  Uncaught TypeError: db2_set_option(): Argument #1 ($resource) must be of type resource, false given in /home/calvin/adodbtest/vendor/adodb/adodb-php/drivers/adodb-db2.inc.php:1591
Stack trace:
#0 /home/calvin/adodbtest/vendor/adodb/adodb-php/drivers/adodb-db2.inc.php(1591): db2_set_option()
#1 /home/calvin/adodbtest/vendor/adodb/adodb-php/adodb-lib.inc.php(1236): ADODB_db2->_query()
#2 /home/calvin/adodbtest/vendor/adodb/adodb-php/adodb.inc.php(1611): _adodb_debug_execute()
#3 /home/calvin/adodbtest/vendor/adodb/adodb-php/adodb.inc.php(1590): ADOConnection->_Execute()
#4 /home/calvin/adodbtest/vendor/adodb/adodb-php/adodb.inc.php(2294): ADOConnection->Execute()
#5 /home/calvin/adodbtest/vendor/adodb/adodb-php/adodb.inc.php(2087): ADOConnection->GetArray()
#6 /home/calvin/adodbtest/index.php(21): ADOConnection->GetAll()
#7 {main}
  thrown in /home/calvin/adodbtest/vendor/adodb/adodb-php/drivers/adodb-db2.inc.php on line 1591

Expected behavior

That it would connect fine.

Additional context

It appears it's because of this block in unpackParameters:

		if ($useCataloguedConnection
		&& (!$argDatabasename
		|| !$argUsername
		|| !$argPassword))
		{

			$errorMessage = 'For catalogued connections, provide ';
			$errorMessage.= 'database, username and password';
			$this->_errorMsg = $errorMessage;
			if ($this->debug)
				ADOConnection::outp($errorMessage);
			return null;

		}

This was introduced in the rewrite of this driver in 5.21.

[dregad]

Same comment as #1032...
I'm sorry but I have zero knowledge of Db2, and no access to an instance of it for testing either, so I won't be able to help you much. Maybe @mnewnham will care to reply.

It doesn't seem to handle this very well, continuing on even though connect returned false

The error stack trace you provided is the result of calling getAll() on a failed connection. It is your responsibility to check connect()'s return value and take appropriate action (e.g. exit program) or use exceptions.

It appears it's because of this block in unpackParameters:
(snip)
This was introduced in the rewrite of this driver in 5.21.

[dregad]

Thanks for the PR @mnewnham

@NattyNarwhal please test Mark's proposed fix in #1034 and let us know if it fixes your problem.