Merge pull request #9287 from weirdan/fix-4092

vimeo · Feb 14, 2023 · 121eef9 · 121eef9
2 parents f73fe36 + 39c992c
commit 121eef9
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diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/NamedFunctionCallHandler.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/NamedFunctionCallHandler.php
@@ -514,6 +514,42 @@ public static function handle(
                 }
             }
         }
+
+        if ($first_arg
+            && $function_id === 'is_a'
+            // assertion reconsiler already emits relevant (but different) issues
+            && !$context->inside_conditional
+        ) {
+            $first_arg_type = $statements_analyzer->node_data->getType($first_arg->value);
+
+            if ($first_arg_type && $first_arg_type->isString()) {
+                $third_arg = $stmt->getArgs()[2] ?? null;
+                if ($third_arg) {
+                    $third_arg_type = $statements_analyzer->node_data->getType($third_arg->value);
+                } else {
+                    $third_arg_type = Type::getFalse();
+                }
+
+                if ($third_arg_type
+                    && $third_arg_type->isSingle()
+                    && $third_arg_type->isFalse()
+                ) {
+                    if ($first_arg_type->from_docblock) {
+                        IssueBuffer::maybeAdd(new RedundantFunctionCallGivenDocblockType(
+                            'Call to is_a always return false when first argument is string '
+                            . 'unless third argument is true',
+                            new CodeLocation($statements_analyzer, $function_name),
+                        ));
+                    } else {
+                        IssueBuffer::maybeAdd(new RedundantFunctionCall(
+                            'Call to is_a always return false when first argument is string '
+                            . 'unless third argument is true',
+                            new CodeLocation($statements_analyzer, $function_name),
+                        ));
+                    }
+                }
+            }
+        }
     }
 
     private static function handleDependentTypeFunction(

diff --git a/tests/FunctionCallTest.php b/tests/FunctionCallTest.php
@@ -2693,6 +2693,54 @@ function takesArrayShapeWithZeroOrPositiveInt(array $foo): void
                 ',
                 'error_message' => 'InvalidArgument',
             ],
+            'is_a_withAStringAndNoThirdArg' => [
+                'code' => '<?php
+                    is_a("Foo", Exception::class);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAStringAndFalseThirdArg' => [
+                'code' => '<?php
+                    is_a("Foo", Exception::class, false);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAUnionOfStringsAndNoThirdArg' => [
+                'code' => '<?php
+                    is_a(rand(0, 1) ? "Foo" : "Bar", Exception::class);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAUnionOfStringsAndFalseThirdArg' => [
+                'code' => '<?php
+                    is_a(rand(0, 1) ? "Foo" : "Bar", Exception::class, false);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAClassStringAndNoThirdArg' => [
+                'code' => '<?php
+                    is_a(InvalidArgumentException::class, Exception::class);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAClassStringAndFalseThirdArg' => [
+                'code' => '<?php
+                    is_a(InvalidArgumentException::class, Exception::class, false);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAUnionOfClassStringsAndNoThirdArg' => [
+                'code' => '<?php
+                    is_a(rand(0, 1) ? InvalidArgumentException::class : RuntimeException::class, Exception::class);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
+            'is_a_withAUnionOfClassStringsAndFalseThirdArg' => [
+                'code' => '<?php
+                    is_a(rand(0, 1) ? InvalidArgumentException::class : RuntimeException::class, Exception::class, false);
+                ',
+                'error_message' => 'RedundantFunctionCall',
+            ],
         ];
     }