Ruleset: hard deprecate support for sniffs not following the naming conventions

The new [About Standards for PHP_CodeSniffer](https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/About-Standards-for-PHP_CodeSniffer) wiki page outlines exactly what the naming conventions are.

This PR adds a new Ruleset deprecation notice for when sniffs are encountered which do not follow these conventions.

Support for sniffs not following the naming conventions will be removed in PHPCS 4.0.

Includes tests.

Includes removing two invalid sniffs from the `ExpandSniffDirectoryTest`. These type of sniffs, which don't comply with the PHPCS naming conventions, are now covered via the new tests.

Related to 689

Author: jrfnl

src/Ruleset.php

@@ -1416,6 +1416,19 @@ public function populateTokenListeners()
             $this->sniffs[$sniffClass] = new $sniffClass();
 
             $sniffCode = Common::getSniffCode($sniffClass);
+
+            if (substr($sniffCode, 0, 1) === '.'
+                || substr($sniffCode, -1) === '.'
+                || strpos($sniffCode, '..') !== false
+                || preg_match('`(^|\.)Sniffs\.`', $sniffCode) === 1
+                || preg_match('`[^\s\.-]+\\\\Sniffs\\\\[^\s\.-]+\\\\[^\s\.-]+Sniff`', $sniffClass) !== 1
+            ) {
+                $message  = "The sniff $sniffClass does not comply with the PHP_CodeSniffer naming conventions.";
+                $message .= ' This will no longer be supported in PHPCS 4.0.'.PHP_EOL;
+                $message .= 'Contact the sniff author to fix the sniff.';
+                $this->msgCache->add($message, MessageCollector::DEPRECATED);
+            }
+
             $this->sniffCodes[$sniffCode] = $sniffClass;
 
             if ($this->sniffs[$sniffClass] instanceof DeprecatedSniff) {

tests/Core/Ruleset/ExpandSniffDirectoryTest.php

@@ -49,20 +49,9 @@ public function testExpandSniffDirectory()
         $this->assertNotFalse($expectedPathToRuleset, 'Ruleset file could not be found');
         $this->assertContains($expectedPathToRuleset, $ruleset->paths, 'Ruleset file not included in the "seen ruleset paths"');
 
-        /*
-         * Take note: the expectation includes some "undesirables" related to the convoluted directory structure
-         * in the "standard" used as a test fixture.
-         *
-         * That is okay as (for now) non-standard directory layouts are supported.
-         *
-         * This test is not about the standard directory layout.
-         */
-
         $expectedSniffCodes = [
-            '.Sniffs.IncorrectLevelShouldStillBeFound'       => 'MyStandard\\Sniffs\\IncorrectLevelShouldStillBeFoundSniff',
-            'MyStandard.CategoryA.FindMe'                    => 'MyStandard\\Sniffs\\CategoryA\\FindMeSniff',
-            'MyStandard.CategoryB.FindMe'                    => 'MyStandard\\Sniffs\\CategoryB\\FindMeSniff',
-            'Sniffs.SubDir.IncorrectLevelShouldStillBeFound' => 'MyStandard\\Sniffs\\CategoryA\\SubDir\\IncorrectLevelShouldStillBeFoundSniff',
+            'MyStandard.CategoryA.FindMe' => 'MyStandard\\Sniffs\\CategoryA\\FindMeSniff',
+            'MyStandard.CategoryB.FindMe' => 'MyStandard\\Sniffs\\CategoryB\\FindMeSniff',
         ];
 
         // Sort the value to make the tests stable as different OSes will read directories

tests/Core/Ruleset/Fixtures/BrokenNamingConventions/Sniffs/Category/Sniff.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Test fixture.
+ *
+ * @see \PHP_CodeSniffer\Tests\Core\RulesetPopulateTokenListenersNamingConventionsTest
+ */
+
+namespace BrokenNamingConventions\Sniffs\Category;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff as PHPCS_Sniff;
+
+final class Sniff implements PHPCS_Sniff
+{
+    public function register()
+    {
+        return [T_OPEN_TAG];
+    }
+
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        // Do something.
+    }
+}

tests/Core/Ruleset/Fixtures/BrokenNamingConventions/Sniffs/Category/SubDir/TooDeeplyNestedSniff.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Test fixture.
+ *
+ * @see \PHP_CodeSniffer\Tests\Core\RulesetPopulateTokenListenersNamingConventionsTest
+ */
+
+namespace BrokenNamingConventions\Sniffs\Category\SubDir;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+final class TooDeeplyNestedSniff implements Sniff
+{
+    public function register()
+    {
+        return [T_OPEN_TAG];
+    }
+
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        // Do something.
+    }
+}

tests/Core/Ruleset/Fixtures/BrokenNamingConventions/Sniffs/MissingCategoryDirSniff.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Test fixture.
+ *
+ * @see \PHP_CodeSniffer\Tests\Core\RulesetPopulateTokenListenersNamingConventionsTest
+ */
+
+namespace BrokenNamingConventions\Sniffs;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+final class MissingCategoryDirSniff implements Sniff
+{
+    public function register()
+    {
+        return [T_OPEN_TAG];
+    }
+
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        // Do something.
+    }
+}

tests/Core/Ruleset/Fixtures/BrokenNamingConventions/Sniffs/NoNamespaceSniff.php

@@ -0,0 +1,22 @@
+<?php
+/**
+ * Test fixture.
+ *
+ * @see \PHP_CodeSniffer\Tests\Core\Ruleset\PopulateTokenListenersNamingConventionsTest
+ */
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+final class NoNamespaceSniff implements Sniff
+{
+    public function register()
+    {
+        return [T_OPEN_TAG];
+    }
+
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        // Do something.
+    }
+}

tests/Core/Ruleset/Fixtures/BrokenNamingConventions/Sniffs/PartialNamespaceSniff.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Test fixture.
+ *
+ * @see \PHP_CodeSniffer\Tests\Core\Ruleset\PopulateTokenListenersNamingConventionsTest
+ */
+
+namespace Sniffs;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+final class PartialNamespaceSniff implements Sniff
+{
+    public function register()
+    {
+        return [T_OPEN_TAG];
+    }
+
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        // Do something.
+    }
+}

tests/Core/Ruleset/Fixtures/BrokenNamingConventions/Sniffs/Sniffs/CategoryCalledSniffsSniff.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * Test fixture.
+ *
+ * @see \PHP_CodeSniffer\Tests\Core\RulesetPopulateTokenListenersNamingConventionsTest
+ */
+
+namespace BrokenNamingConventions\Sniffs\Sniffs;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+final class CategoryCalledSniffsSniff implements Sniff
+{
+    public function register()
+    {
+        return [T_OPEN_TAG];
+    }
+
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        // Do something.
+    }
+}