Generic/RequireStrictTypes: add warning for when value is 0

Strict types is disabled when the value for the `strict_types` directive is `0`.

As this sniff is supposed to be about enforcing the use of `strict_types`, `strict_types` declarations which turn the feature off should be flagged as well.

Implemented with a separate error code to allow for selectively turning this warning off.

Includes dedicated tests.

Author: jrfnl

CHANGELOG.md

@@ -77,6 +77,9 @@ The file documents changes to the PHP_CodeSniffer project.
     - Thanks to Juliette Reinders Folmer (@jrfnl) for the patch
 - Generic.Functions.OpeningFunctionBraceKernighanRitchie will now check the spacing before the opening brace for empty functions
     - Thanks to Juliette Reinders Folmer (@jrfnl) for the patch
+- Generic.PHP.RequireStrictTypes has a new warning for when there is a declare statement, but the strict_types directive is set to 0
+    - The warning can be turned off by excluding the Generic.PHP.RequireStrictTypes.Disabled error code
+    - Thanks to Juliette Reinders Folmer (@jrfnl) for the patch
 - PSR2.Classes.PropertyDeclaration now enforces that the readonly modifier comes after the visibility modifier
     - PSR2 and PSR12 do not have documented rules for this as they pre-date the readonly modifier
     - PSR-PER has been used to confirm the order of this keyword so it can be applied to PSR2 and PSR12 correctly

src/Standards/Generic/Sniffs/PHP/RequireStrictTypesSniff.php

@@ -77,6 +77,25 @@ public function process(File $phpcsFile, $stackPtr)
         if ($found === false) {
             $error = 'Missing required strict_types declaration';
             $phpcsFile->addError($error, $stackPtr, 'MissingDeclaration');
+
+            return $phpcsFile->numTokens;
+        }
+
+        // Strict types declaration found, make sure strict types is enabled.
+        $skip     = Tokens::$emptyTokens;
+        $skip[]   = T_EQUAL;
+        $valuePtr = $phpcsFile->findNext($skip, ($next + 1), null, true);
+
+        if ($valuePtr !== false
+            && $tokens[$valuePtr]['code'] === T_LNUMBER
+            && $tokens[$valuePtr]['content'] === '0'
+        ) {
+            $error = 'Required strict_types declaration found, but strict types is disabled. Set the value to 1 to enable';
+            $fix   = $phpcsFile->addFixableWarning($error, $valuePtr, 'Disabled');
+
+            if ($fix === true) {
+                $phpcsFile->fixer->replaceToken($valuePtr, '1');
+            }
         }
 
         // Skip the rest of the file so we don't pick up additional

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.11.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=0);
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.11.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.12.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare(  strict_types  =   /*comment*/   0   );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.12.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare(  strict_types  =   /*comment*/   1   );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.13.inc

@@ -0,0 +1,3 @@
+<?php
+// Safeguard sniff handles parse error/live coding correctly.
+declare(strict_types=

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.14.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare( strict_types = 0, encoding='utf-8' );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.14.inc.fixed

@@ -0,0 +1,5 @@
+<?php
+
+declare( strict_types = 1, encoding='utf-8' );
+
+// some code

src/Standards/Generic/Tests/PHP/RequireStrictTypesUnitTest.15.inc

@@ -0,0 +1,5 @@
+<?php
+
+declare(encoding='utf-8', strict_types=0);
+
+// some code