Declare multiple mysqli_ functions as impure

bin/functionMetadata_original.php

@@ -94,6 +94,7 @@
 	'link' => ['hasSideEffects' => true],
 	'mkdir' => ['hasSideEffects' => true],
 	'move_uploaded_file' => ['hasSideEffects' => true],
+	'mysqli_connect' => ['hasSideEffects' => true],
 	'ob_clean' => ['hasSideEffects' => true],
 	'ob_end_clean' => ['hasSideEffects' => true],
 	'ob_end_flush' => ['hasSideEffects' => true],

resources/functionMetadata.php

@@ -1392,6 +1392,7 @@
 	'msgfmt_parse_message' => ['hasSideEffects' => false],
 	'mt_getrandmax' => ['hasSideEffects' => false],
 	'mt_rand' => ['hasSideEffects' => true],
+	'mysqli_connect' => ['hasSideEffects' => true],
 	'net_get_interfaces' => ['hasSideEffects' => false],
 	'ngettext' => ['hasSideEffects' => false],
 	'nl2br' => ['hasSideEffects' => false],

tests/PHPStan/Rules/Comparison/BooleanOrConstantConditionRuleTest.php

@@ -384,4 +384,11 @@ public function testBug10305(): void
 		]);
 	}
 
+	public function testBug14473(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+
+		$this->analyse([__DIR__ . '/data/bug-14473.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-14473.php

@@ -0,0 +1,27 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14473;
+
+$link = mysqli_connect('host', 'user', 'pass', 'database') or die('Could not connect: ' . mysqli_connect_error());
+
+// (assume long-running code that can cause the connection to time out)
+
+$link = mysqli_connect('host', 'user', 'pass', 'database') or die('Could not reconnect: ' . mysqli_connect_error());
+
+// okay, so let's make certain that the connection is closed
+mysqli_close($link);
+
+$link = mysqli_connect('host', 'user', 'pass', 'database') or die('Could not reconnect: ' . mysqli_connect_error());
+
+// close it and destroy the variable
+mysqli_close($link);
+unset($link);
+
+$link = mysqli_connect('host', 'user', 'pass', 'database') or die('Could not reconnect: ' . mysqli_connect_error());
+
+// close, destroy ...
+mysqli_close($link);
+unset($link);
+
+// ... and assign to a different variable
+$newLink = mysqli_connect('host', 'user', 'pass', 'database') or die('Could not reconnect: ' . mysqli_connect_error());