Fix phpstan/phpstan#5865: Do-while loop broken by exception not supported

Detect void methods/functions that always terminate (throw/exit) during
body analysis and suppress false "always true/false" loop condition
reports when such calls appear in loop bodies.

Author: github-actions[bot]

src/Analyser/NodeScopeResolver.php

@@ -194,6 +194,9 @@ class NodeScopeResolver
 	/** @var array<string, true> */
 	private array $earlyTerminatingMethodNames;
 
+	/** @var array<string, true> */
+	private array $alwaysTerminatingCallables = [];
+
 	/** @var array<string, true> */
 	private array $calledMethodStack = [];
 
@@ -660,6 +663,15 @@ public function processStmtNode(
 				array_merge($statementResult->getImpurePoints(), $functionImpurePoints),
 				$functionReflection,
 			), $functionScope, $storage);
+
+			if (
+				count($gatheredReturnStatements) === 0
+				&& count($gatheredYieldStatements) === 0
+				&& $this->isBodyAlwaysTerminating($executionEnds)
+			) {
+				$this->alwaysTerminatingCallables[strtolower($functionReflection->getName())] = true;
+			}
+
 			if (!$scope->isInAnonymousFunction()) {
 				$this->processPendingFibers($storage);
 			}
@@ -825,6 +837,14 @@ public function processStmtNode(
 					$methodReflection,
 				), $methodScope, $storage);
 
+				if (
+					count($gatheredReturnStatements) === 0
+					&& count($gatheredYieldStatements) === 0
+					&& $this->isBodyAlwaysTerminating($executionEnds)
+				) {
+					$this->alwaysTerminatingCallables[strtolower($classReflection->getName() . '::' . $methodReflection->getName())] = true;
+				}
+
 				if ($isConstructor) {
 					$finalScope = null;
 
@@ -2454,12 +2474,23 @@ private function findEarlyTerminatingExpr(Expr $expr, Scope $scope): ?Expr
 					}
 				}
 			}
+
+			if (!$expr->isFirstClassCallable() && $this->isMethodCallAlwaysTerminating($expr, $scope)) {
+				return $expr;
+			}
 		}
 
 		if ($expr instanceof FuncCall && $expr->name instanceof Name) {
 			if (in_array((string) $expr->name, $this->earlyTerminatingFunctionCalls, true)) {
 				return $expr;
 			}
+
+			if (!$expr->isFirstClassCallable()) {
+				$resolvedFunctionName = $this->reflectionProvider->resolveFunctionName($expr->name, $scope);
+				if ($resolvedFunctionName !== null && isset($this->alwaysTerminatingCallables[strtolower($resolvedFunctionName)])) {
+					return $expr;
+				}
+			}
 		}
 
 		if ($expr instanceof Expr\Exit_ || $expr instanceof Expr\Throw_) {
@@ -2474,6 +2505,50 @@ private function findEarlyTerminatingExpr(Expr $expr, Scope $scope): ?Expr
 		return null;
 	}
 
+	private function isMethodCallAlwaysTerminating(MethodCall|Expr\StaticCall $expr, Scope $scope): bool
+	{
+		if (!$expr->name instanceof Node\Identifier) {
+			return false;
+		}
+
+		if ($expr instanceof MethodCall) {
+			$methodCalledOnType = $scope->getType($expr->var);
+		} else {
+			if ($expr->class instanceof Name) {
+				$methodCalledOnType = $scope->resolveTypeByName($expr->class);
+			} else {
+				$methodCalledOnType = $scope->getType($expr->class);
+			}
+		}
+
+		foreach ($methodCalledOnType->getObjectClassNames() as $referencedClass) {
+			$key = strtolower($referencedClass . '::' . $expr->name->toLowerString());
+			if (isset($this->alwaysTerminatingCallables[$key])) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * @param ExecutionEndNode[] $executionEnds
+	 */
+	private function isBodyAlwaysTerminating(array $executionEnds): bool
+	{
+		if ($executionEnds === []) {
+			return false;
+		}
+
+		foreach ($executionEnds as $executionEnd) {
+			if (!$executionEnd->getStatementResult()->isAlwaysTerminating()) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+
 	/**
 	 * @param callable(Node $node, Scope $scope): void $nodeCallback
 	 */

tests/PHPStan/Rules/Comparison/DoWhileLoopConstantConditionRuleTest.php

@@ -29,6 +29,11 @@ protected function getRule(): Rule
 		);
 	}
 
+	public function testBug5865(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5865.php'], []);
+	}
+
 	public function testBug6189(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-6189.php'], []);

tests/PHPStan/Rules/Comparison/WhileLoopAlwaysTrueConditionRuleTest.php

@@ -60,6 +60,11 @@ public function testBug10054(): void
 		$this->analyse([__DIR__ . '/data/bug-10054.php'], []);
 	}
 
+	public function testBug5865(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5865-while.php'], []);
+	}
+
 	public function testBug6189(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-6189.php'], [

tests/PHPStan/Rules/Comparison/data/bug-5865-while.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Bug5865While;
+
+final class HelloWorld
+{
+
+	public function alwaysThrows(): void
+	{
+		throw new \Exception();
+	}
+
+	public function whileLiteralTrue(): void
+	{
+		while (true) {
+			$this->alwaysThrows();
+		}
+	}
+
+	public static function staticAlwaysThrows(): void
+	{
+		throw new \Exception();
+	}
+
+	public function whileStaticCall(): void
+	{
+		while (true) {
+			self::staticAlwaysThrows();
+		}
+	}
+
+}
+
+function alwaysThrowsFunction(): void
+{
+	throw new \Exception();
+}
+
+function whileFunctionCall(): void
+{
+	while (true) {
+		alwaysThrowsFunction();
+	}
+}

tests/PHPStan/Rules/Comparison/data/bug-5865.php

@@ -0,0 +1,65 @@
+<?php
+
+namespace Bug5865;
+
+final class HelloWorld
+{
+
+	public function alwaysThrows(): void
+	{
+		throw new \Exception();
+	}
+
+	public function doWhileLiteralTrue(): void
+	{
+		do {
+			$this->alwaysThrows();
+		} while (true); // should not report - body always terminates
+	}
+
+	public function doWhileVariableCondition(): void
+	{
+		$a = true;
+		do {
+			$this->alwaysThrows();
+			$a = false;
+		} while ($a); // should not report - body always terminates
+	}
+
+	public function neverReturnType(): never
+	{
+		throw new \Exception();
+	}
+
+	public function doWhileNeverReturnType(): void
+	{
+		do {
+			$this->neverReturnType();
+		} while (true); // already works - no error
+	}
+
+	public static function staticAlwaysThrows(): void
+	{
+		throw new \Exception();
+	}
+
+	public function doWhileStaticCall(): void
+	{
+		do {
+			self::staticAlwaysThrows();
+		} while (true); // should not report - body always terminates
+	}
+
+}
+
+function alwaysThrowsFunction(): void
+{
+	throw new \Exception();
+}
+
+function doWhileFunctionCall(): void
+{
+	do {
+		alwaysThrowsFunction();
+	} while (true); // should not report - body always terminates
+}