Ignore json_decode and json_encode when use JSON_THROW_ON_ERROR option

src/Rules/UseSafeFunctionsRule.php

@@ -10,6 +10,9 @@
 use PHPStan\Rules\Rule;
 use PHPStan\ShouldNotHappenException;
 use TheCodingMachine\Safe\PHPStan\Utils\FunctionListLoader;
+use PhpParser\Node\Arg;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Scalar;
 
 /**
  * This rule checks that no superglobals are used in code.
@@ -35,9 +38,53 @@ public function processNode(Node $node, Scope $scope): array
         $unsafeFunctions = FunctionListLoader::getFunctionList();
 
         if (isset($unsafeFunctions[$functionName])) {
+            if (version_compare(PHP_VERSION, '7.3.0', '>=')) {
+                if ($functionName === "json_decode") {
+                    if (count($node->args) == 4) {
+                        if ($this->argValueIncludeJSONTHROWONERROR($node->args[3])) {
+                            return [];
+                        }
+                    }
+                }
+                if ($functionName === "json_encode") {
+                    if (count($node->args) >= 2) {
+                        if ($this->argValueIncludeJSONTHROWONERROR($node->args[1])) {
+                            return [];
+                        }
+                    }
+                }
+            }
+
             return ["Function $functionName is unsafe to use. It can return FALSE instead of throwing an exception. Please add 'use function Safe\\$functionName;' at the beginning of the file to use the variant provided by the 'thecodingmachine/safe' library."];
         }
 
         return [];
     }
+
+    private function argValueIncludeJSONTHROWONERROR(Arg $arg): bool
+    {
+        $parseValue = function ($expr, array $options) use (&$parseValue): array {
+            if ($expr instanceof Expr\BinaryOp\BitwiseOr) {
+                return array_merge($parseValue($expr->left, $options), $parseValue($expr->right, $options));
+            } elseif ($expr instanceof Expr\ConstFetch) {
+                return array_merge($options, $expr->name->parts);
+            } elseif ($expr instanceof Scalar\LNumber) {
+                return array_merge($options, [$expr->value]);
+            } else {
+                return $options;
+            }
+        };
+        $options = $parseValue($arg->value, []);
+
+        if (in_array("JSON_THROW_ON_ERROR", $options)) {
+            return true;
+        }
+
+        return in_array(true, array_map(function ($element) {
+            // JSON_THROW_ON_ERROR == 4194304
+            return ($element & 4194304) == 4194304;
+        }, array_filter($options, function ($element) {
+            return is_int($element);
+        })));
+    }
 }

tests/Rules/UseSafeFunctionsRuleTest.php

@@ -31,4 +31,22 @@ public function testExprCall()
     {
         $this->analyse([__DIR__ . '/data/undirect_call.php'], []);
     }
+
+    public function testJSONDecodeNoCatchSafe()
+    {
+        if (version_compare(PHP_VERSION, '7.3.0', '>=')) {
+            $this->analyse([__DIR__ . '/data/safe_json_decode_for_7.3.0.php'], []);
+        } else {
+            $this->assertTrue(true);
+        }
+    }
+
+    public function testJSONEncodeNoCatchSafe()
+    {
+        if (version_compare(PHP_VERSION, '7.3.0', '>=')) {
+            $this->analyse([__DIR__ . '/data/safe_json_encode_for_7.3.0.php'], []);
+        } else {
+            $this->assertTrue(true);
+        }
+    }
 }

tests/Rules/data/safe_json_decode_for_7.3.0.php

@@ -0,0 +1,9 @@
+<?php
+
+json_decode("{}", true, 512, JSON_THROW_ON_ERROR);
+json_decode("{}", true, 512, JSON_INVALID_UTF8_IGNORE | JSON_THROW_ON_ERROR);
+json_decode("{}", true, 512, JSON_INVALID_UTF8_IGNORE | JSON_OBJECT_AS_ARRAY | JSON_THROW_ON_ERROR);
+
+json_decode("{}", true, 512, 4194304);
+json_decode("{}", true, 512, 1048576 | 4194304);
+json_decode("{}", true, 512, 1048576 | 1 | 4194304);

tests/Rules/data/safe_json_encode_for_7.3.0.php

@@ -0,0 +1,5 @@
+<?php
+
+json_encode([], JSON_THROW_ON_ERROR, 512);
+json_encode([], JSON_FORCE_OBJECT | JSON_THROW_ON_ERROR, 512);
+json_encode([], JSON_FORCE_OBJECT | JSON_INVALID_UTF8_IGNORE | JSON_THROW_ON_ERROR, 512);