Fix SessionHandlerInterface::read return type

resources/functionMap.php

@@ -10421,7 +10421,7 @@
 'SessionHandlerInterface::destroy' => ['bool', 'session_id'=>'string'],
 'SessionHandlerInterface::gc' => ['int|false', 'maxlifetime'=>'int'],
 'SessionHandlerInterface::open' => ['bool', 'save_path'=>'string', 'name'=>'string'],
-'SessionHandlerInterface::read' => ['string', 'session_id'=>'string'],
+'SessionHandlerInterface::read' => ['string|false', 'session_id'=>'string'],
 'SessionHandlerInterface::write' => ['bool', 'session_id'=>'string', 'session_data'=>'string'],
 'SessionIdInterface::create_sid' => ['string'],
 'SessionUpdateTimestampHandler::updateTimestamp' => ['bool', 'id'=>'string', 'data'=>'string'],

tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php

@@ -1006,4 +1006,9 @@ public function testBug12772(): void
 		$this->analyse([__DIR__ . '/data/bug-12772.php'], []);
 	}
 
+	public function testBug12748(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-12748.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-12748.php

@@ -0,0 +1,54 @@
+<?php declare(strict_types = 1); // lint >= 8.0
+
+namespace Bug12748;
+
+use SessionHandlerInterface;
+
+class HelloWorld
+{
+	public function getHandler(): SessionHandlerInterface
+	{
+		return new SessHandler;
+	}
+}
+
+class SessHandler implements SessionHandlerInterface
+{
+
+    public function close(): bool
+    {
+        return true;
+    }
+
+    public function destroy(string $id): bool
+    {
+        return true;
+    }
+
+    public function gc(int $max_lifetime): int|false
+    {
+        return false;
+    }
+
+    public function open(string $path, string $name): bool
+    {
+        return true;
+    }
+
+    public function read(string $id): string|false
+    {
+        return false;
+    }
+
+    public function write(string $id, string $data): bool
+    {
+        return true;
+    }
+}
+
+$sessionHandler = (new HelloWorld)->getHandler();
+$session = $sessionHandler->read('123');
+
+if ($session === false) {
+	return null;
+}