- added exclude for */Fixtures/* files;

- added `ForeachArrayMergeSniff` documentation with `HowTo Fix` example;
- major version bump.

Author: lenaorobei

Magento2/Sniffs/Performance/ForeachArrayMergeSniff.md

@@ -0,0 +1,26 @@
+# Rule: array_merge(...) is used in a loop and is a resources greedy construction
+
+## Reason
+Merging arrays in a loop is slow and causes high CPU usage.
+
+## How to Fix
+Typical example when `array_merge` is being used in the loop:
+``` php
+    $options = [];
+    foreach ($configurationSources as $source) {
+        // code here
+        $options = array_merge($options, $source->getOptions());
+    }
+```
+
+In order to reduce execution time `array_merge` can be called only once:
+``` php
+    $options = [[]];
+    foreach ($configurationSources as $source) {
+        // code here
+        $options[] = $source->getOptions();
+    }
+
+    // PHP 5.6+
+    $options = array_merge(...$options);
+```

Magento2/ruleset.xml

@@ -31,7 +31,10 @@
     <rule ref="Magento2.Classes.DiscouragedDependencies">
         <severity>10</severity>
         <type>error</type>
+        <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
+        <exclude-pattern>*Test.php</exclude-pattern>
     </rule>
     <rule ref="Magento2.Legacy.MageEntity">
         <severity>10</severity>
@@ -57,6 +60,7 @@
         <severity>10</severity>
         <type>error</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
     </rule>
@@ -68,6 +72,7 @@
         <severity>10</severity>
         <type>error</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/lib/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
@@ -103,6 +108,7 @@
         <severity>9</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/lib/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
@@ -116,6 +122,7 @@
         <severity>9</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/lib/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
@@ -134,6 +141,7 @@
         <severity>8</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
     </rule>
@@ -145,6 +153,7 @@
         <severity>8</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/lib/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
@@ -153,6 +162,7 @@
         <severity>8</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/lib/*</exclude-pattern>
         <exclude-pattern>*/Setup/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
@@ -224,6 +234,7 @@
         <severity>7</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
     </rule>
@@ -251,6 +262,7 @@
         <severity>7</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
     </rule>
@@ -266,6 +278,7 @@
         <severity>7</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
     </rule>
@@ -329,6 +342,7 @@
         <severity>6</severity>
         <type>warning</type>
         <exclude-pattern>*/_files/*</exclude-pattern>
+        <exclude-pattern>*/Fixtures/*</exclude-pattern>
         <exclude-pattern>*/Test/*</exclude-pattern>
         <exclude-pattern>*Test.php</exclude-pattern>
     </rule>

composer.json

@@ -6,7 +6,7 @@
         "AFL-3.0"
     ],
     "type": "phpcodesniffer-standard",
-    "version": "1.0.2",
+    "version": "2.0.0",
     "require": {
         "php": ">=5.6.0",
         "squizlabs/php_codesniffer": "~3.3.0"