From 2261d765bf8016223d0b7cb3f9f4bdd93f3ee4a1 Mon Sep 17 00:00:00 2001
From: Dariusz Ruminski <dariusz.ruminski@gmail.com>
Date: Fri, 12 Mar 2021 20:56:17 +0100
Subject: [PATCH] DX: RuleSet - convert null handling to soft-warning

---
 src/RuleSet/RuleSet.php    | 24 +++++++++++++++++++++---
 tests/FixerFactoryTest.php |  2 +-
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/RuleSet/RuleSet.php b/src/RuleSet/RuleSet.php
index 22f50287a71..ea57d8512d0 100644
--- a/src/RuleSet/RuleSet.php
+++ b/src/RuleSet/RuleSet.php
@@ -39,13 +39,31 @@ class RuleSet implements RuleSetInterface
 
     public function __construct(array $set = [])
     {
-        foreach ($set as $key => $value) {
-            if (\is_int($key)) {
+        foreach ($set as $name => $value) {
+            if ('' === $name) {
+                throw new \InvalidArgumentException('Rule/set name must not be empty.');
+            }
+
+            if (\is_int($name)) {
                 throw new \InvalidArgumentException(sprintf('Missing value for "%s" rule/set.', $value));
             }
 
             if (true !== $value && false !== $value && !\is_array($value)) {
-                throw new InvalidFixerConfigurationException($key, 'Configuration must be an array and may not be empty.');
+                // @TODO drop me on 3.0
+                if (null === $value) {
+                    $messageForNullIssue = 'To disable the rule, use "FALSE" instead of "NULL".';
+                    if (getenv('PHP_CS_FIXER_FUTURE_MODE')) {
+                        throw new InvalidFixerConfigurationException($name, $messageForNullIssue);
+                    }
+
+                    @trigger_error($messageForNullIssue, E_USER_DEPRECATED);
+
+                    continue;
+                }
+
+                $message = '@' === $name[0] ? 'Set must be enabled (true) or disabled (false). Other values are not allowed.' : 'Rule must be enabled (true), disabled (false) or configured (non-empty, assoc array). Other values are not allowed.';
+
+                throw new InvalidFixerConfigurationException($name, $message);
             }
         }
 
diff --git a/tests/FixerFactoryTest.php b/tests/FixerFactoryTest.php
index abc0e8c8b66..f4a932fcb60 100644
--- a/tests/FixerFactoryTest.php
+++ b/tests/FixerFactoryTest.php
@@ -308,7 +308,7 @@ public function testConfigureFixerWithNonArray($value)
             \PhpCsFixer\ConfigurationException\InvalidFixerConfigurationException::class
         );
         $this->expectExceptionMessage(
-            '[foo] Configuration must be an array and may not be empty.'
+            '[foo] Rule must be enabled (true), disabled (false) or configured (non-empty, assoc array). Other values are not allowed.'
         );
 
         $factory->useRuleSet(new RuleSet([