Fix false positive undefined variable when breaking out of infinite loop

- In while(true) loops, the only way to exit is via break, so the post-loop scope should be constructed solely from break exit point scopes
- Previously, break scopes were merged with the "normal exit" scope (filterByFalseyValue), which degraded variable certainty to "maybe" for variables only defined in the break path
- New regression test in tests/PHPStan/Rules/Variables/data/bug-9023.php

Closes phpstan/phpstan#9023

Author: phpstan-bot

src/Analyser/NodeScopeResolver.php

@@ -1517,8 +1517,16 @@ private function processStmtNode(
 			}
 
 			$breakExitPoints = $finalScopeResult->getExitPointsByType(Break_::class);
-			foreach ($breakExitPoints as $breakExitPoint) {
-				$finalScope = $finalScope->mergeWith($breakExitPoint->getScope());
+			if ($alwaysIterates && count($breakExitPoints) > 0) {
+				$breakScope = null;
+				foreach ($breakExitPoints as $breakExitPoint) {
+					$breakScope = $breakScope === null ? $breakExitPoint->getScope() : $breakScope->mergeWith($breakExitPoint->getScope());
+				}
+				$finalScope = $breakScope;
+			} else {
+				foreach ($breakExitPoints as $breakExitPoint) {
+					$finalScope = $finalScope->mergeWith($breakExitPoint->getScope());
+				}
 			}
 
 			$isIterableAtLeastOnce = $beforeCondBooleanType->isTrue()->yes();

tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php

@@ -1257,4 +1257,14 @@ public function testBug12944(): void
 		$this->analyse([__DIR__ . '/data/bug-12944.php'], []);
 	}
 
+	public function testBug9023(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+
+		$this->analyse([__DIR__ . '/data/bug-9023.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Variables/data/bug-9023.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace Bug9023;
+
+use Exception;
+
+function unreliableFunc(): string
+{
+	if (random_int(1, 5) === 1) {
+		return 'something';
+	} else {
+		throw new Exception('Just demonstrating');
+	}
+}
+
+function testWhileTrueBreakWithTryCatch(): void
+{
+	while (true) {
+		try {
+			$defined = unreliableFunc();
+			break;
+		} catch (Exception $e) {
+			sleep(10);
+			continue;
+		}
+	}
+
+	echo $defined;
+}