Declare multiple mysqli_ functions as impure

src/Analyser/ExprHandler/AssignHandler.php

@@ -45,6 +45,7 @@
 use PHPStan\Node\PropertyAssignNode;
 use PHPStan\Node\VariableAssignNode;
 use PHPStan\Php\PhpVersion;
+use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\Accessory\AccessoryArrayListType;
@@ -84,6 +85,7 @@ final class AssignHandler implements ExprHandler
 	public function __construct(
 		private TypeSpecifier $typeSpecifier,
 		private PhpVersion $phpVersion,
+		private ReflectionProvider $reflectionProvider,
 	)
 	{
 	}
@@ -861,10 +863,13 @@ private function processSureTypesForConditionalExpressionsAfterAssign(Scope $sco
 				if ($expr->name === $variableName) {
 					continue;
 				}
+			} elseif ($expr instanceof FuncCall) {
+				if ($this->isBuiltinFunctionCallWithPossibleSideEffects($expr, $scope)) {
+					continue;
+				}
 			} elseif (
 				!$expr instanceof PropertyFetch
 				&& !$expr instanceof ArrayDimFetch
-				&& !$expr instanceof FuncCall
 			) {
 				continue;
 			}
@@ -900,10 +905,13 @@ private function processSureNotTypesForConditionalExpressionsAfterAssign(Scope $
 				if ($expr->name === $variableName) {
 					continue;
 				}
+			} elseif ($expr instanceof FuncCall) {
+				if ($this->isBuiltinFunctionCallWithPossibleSideEffects($expr, $scope)) {
+					continue;
+				}
 			} elseif (
 				!$expr instanceof PropertyFetch
 				&& !$expr instanceof ArrayDimFetch
-				&& !$expr instanceof FuncCall
 			) {
 				continue;
 			}
@@ -924,6 +932,21 @@ private function processSureNotTypesForConditionalExpressionsAfterAssign(Scope $
 		return $conditionalExpressions;
 	}
 
+	private function isBuiltinFunctionCallWithPossibleSideEffects(Expr $expr, Scope $scope): bool
+	{
+		if (!$expr instanceof FuncCall || !$expr->name instanceof Name) {
+			return false;
+		}
+
+		if (!$this->reflectionProvider->hasFunction($expr->name, $scope)) {
+			return false;
+		}
+
+		$functionReflection = $this->reflectionProvider->getFunction($expr->name, $scope);
+
+		return $functionReflection->isBuiltin() && !$functionReflection->hasSideEffects()->no();
+	}
+
 	/**
 	 * @param list<ArrayDimFetch> $dimFetchStack
 	 */

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());