Fix weird "If string is a valid class string" tip

Author: paulbalandan

src/Rules/Functions/FactoriesFunctionArgumentTypeRule.php

@@ -84,16 +84,24 @@ public function processNode(Node $node, Scope $scope): array
         )->getParameters()[0];
 
         if ($returnType->isNull()->yes()) {
-            return [RuleErrorBuilder::message(sprintf(
+            $addTip = static function (RuleErrorBuilder $ruleErrorBuilder) use ($nameType, $function): RuleErrorBuilder {
+                if ($nameType->getConstantStrings() === []) {
+                    return $ruleErrorBuilder;
+                }
+
+                return $ruleErrorBuilder->tip(sprintf(
+                    'If %s is a valid class string, you can add its possible namespace(s) in <fg=cyan>codeigniter.additional%sNamespaces</> in your <fg=yellow>%%configurationFile%%</>.',
+                    $nameType->describe(VerbosityLevel::precise()),
+                    ucfirst($function)
+                ));
+            };
+
+            return [$addTip(RuleErrorBuilder::message(sprintf(
                 'Parameter #1 $%s of function %s expects a valid class string, %s given.',
                 $firstParameter->getName(),
                 $function,
                 $nameType->describe(VerbosityLevel::precise())
-            ))->tip(sprintf(
-                'If %s is a valid class string, you can add its possible namespace(s) in <fg=cyan>codeigniter.additional%sNamespaces</> in your <fg=yellow>%%configurationFile%%</>.',
-                $nameType->describe(VerbosityLevel::precise()),
-                ucfirst($function)
-            ))->identifier(sprintf('codeigniter.%sArgumentType', $function))->build()];
+            )))->identifier(sprintf('codeigniter.%sArgumentType', $function))->build()];
         }
 
         if (! (new ObjectType($this->instanceofMap[$function]))->isSuperTypeOf($returnType)->yes()) {

tests/Fixtures/Type/config.php

@@ -31,4 +31,6 @@ function bar(string $name): void
     if (class_exists($name)) {
         assertType('object', config($name));
     }
+
+    assertType('null', config($name));
 }

tests/Rules/Functions/FactoriesFunctionArgumentTypeRuleTest.php

@@ -62,6 +62,10 @@ public function testRule(): void
                 'Argument #1 $name (class-string) passed to function config does not extend CodeIgniter\\\\Config\\\\BaseConfig.',
                 32,
             ],
+            [
+                'Parameter #1 $name of function config expects a valid class string, string given.',
+                35,
+            ],
             [
                 'Parameter #1 $name of function model expects a valid class string, \'foo\' given.',
                 18,