Option for undefined vars (#56)

* Add option to ignore variable seen as undefined

Rather than declaring `global $post` on every single WordPress theme part, I find this option useful, especially when reviewing third-party themes that would otherwise have many warnings.

* Add tests

* update readme

Author: brandonkal

Diff for: README.md

@@ -66,6 +66,7 @@ The available options are as follows:
 - `allowUnusedCaughtExceptions` (bool, default `false`): if set to true, caught Exception variables will never be marked as unused.
 - `validUnusedVariableNames` (string, default `null`): a space-separated list of names of placeholder variables that you want to ignore from unused variable warnings. For example, to ignore the variables `$junk` and `$unused`, this could be set to `'junk unused'`.
 - `ignoreUnusedRegexp` (string, default `null`): a PHP regexp string (note that this requires explicit delimiters) for variables that you want to ignore from unused variable warnings. For example, to ignore the variables `$_junk` and `$_unused`, this could be set to `'/^_/'`.
+- `validUndefinedVariableNames` (string, default `null`): a space-separated list of names of placeholder variables that you want to ignore from undefined variable warnings. For example, to ignore the variables `$post` and `$undefined`, this could be set to `'post undefined'`.
 
 To set these these options, you must use XML in your ruleset. For details, see the [phpcs customizable sniff properties page](https://github.com/squizlabs/PHP_CodeSniffer/wiki/Customisable-Sniff-Properties). Here is an example that ignores all variables that start with an underscore:
 

Diff for: VariableAnalysis/Lib/VariableInfo.php

@@ -17,6 +17,7 @@ class VariableInfo {
   public $firstInitialized;
   public $firstRead;
   public $ignoreUnused = false;
+  public $ignoreUndefined = false;
 
   public static $scopeTypeDescriptions = array(
     'local'  => 'variable',

Diff for: VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php

@@ -54,6 +54,13 @@ class VariableAnalysisSniff implements Sniff {
    */
   public $ignoreUnusedRegexp = null;
 
+  /**
+   *  A space-separated list of names of placeholder variables that you want to
+   *  ignore from undefined variable warnings. For example, to ignore the variables
+   *  `$post` and `$undefined`, this could be set to `'post undefined'`.
+   */
+  public $validUdefinedVariableNames = null;
+
   public function register() {
     return [
       T_VARIABLE,
@@ -130,12 +137,18 @@ protected function getOrCreateVariableInfo($varName, $currScope) {
       $validUnusedVariableNames = (empty($this->validUnusedVariableNames))
         ? []
         : preg_split('/\s+/', trim($this->validUnusedVariableNames));
+      $validUndefinedVariableNames = (empty($this->validUndefinedVariableNames))
+        ? []
+        : preg_split('/\s+/', trim($this->validUndefinedVariableNames));
       if (in_array($varName, $validUnusedVariableNames)) {
         $scopeInfo->variables[$varName]->ignoreUnused = true;
       }
       if (isset($this->ignoreUnusedRegexp) && preg_match($this->ignoreUnusedRegexp, $varName) === 1) {
         $scopeInfo->variables[$varName]->ignoreUnused = true;
       }
+      if (in_array($varName, $validUndefinedVariableNames)) {
+        $scopeInfo->variables[$varName]->ignoreUndefined = true;
+      }
     }
     return $scopeInfo->variables[$varName];
   }
@@ -206,6 +219,9 @@ protected function isVariableInitialized($varName, $stackPtr, $currScope) {
 
   protected function isVariableUndefined($varName, $stackPtr, $currScope) {
     $varInfo = $this->getVariableInfo($varName, $currScope);
+    if ($varInfo->ignoreUndefined) {
+      return false;
+    }
     if (isset($varInfo->firstDeclared) && $varInfo->firstDeclared <= $stackPtr) {
       // TODO: do we want to check scopeType here?
       return false;

Diff for: VariableAnalysis/Tests/CodeAnalysis/VariableAnalysisTest.php

@@ -84,7 +84,10 @@ public function testFunctionWithGlobalVarWarnings() {
     $expectedWarnings = [
       4,
       7,
-      22,
+      8,
+      23,
+      28,
+      29
     ];
     $this->assertEquals($expectedWarnings, $lines);
   }
@@ -355,8 +358,12 @@ public function testClassReferenceWarnings() {
     $expectedWarnings = [
       10,
       11,
-      20,
-      21,
+      12,
+      13,
+      22,
+      23,
+      24,
+      25
     ];
     $this->assertEquals($expectedWarnings, $lines);
   }
@@ -553,4 +560,43 @@ public function testAllowDestructuringAssignment() {
     ];
     $this->assertEquals($expectedWarnings, $lines);
   }
+
+  public function testValidUndefinedVariableNamesIgnoresVarsInGlobalScope() {
+    $fixtureFile = $this->getFixture('FunctionWithGlobalVarFixture.php');
+    $phpcsFile = $this->prepareLocalFileForSniffs($this->getSniffFiles(), $fixtureFile);
+    $phpcsFile->ruleset->setSniffProperty(
+      'VariableAnalysis\Sniffs\CodeAnalysis\VariableAnalysisSniff',
+      'validUndefinedVariableNames',
+      'ice_cream'
+    );
+    $phpcsFile->process();
+    $lines = $this->getWarningLineNumbersFromFile($phpcsFile);
+    $expectedWarnings = [
+      4,
+      7,
+      23,
+    ];
+    $this->assertEquals($expectedWarnings, $lines);
+  }
+
+  public function testValidUndefinedVariableNamesIgnoresUndefinedProperties() {
+    $fixtureFile = $this->getFixture('ClassReferenceFixture.php');
+    $phpcsFile = $this->prepareLocalFileForSniffs($this->getSniffFiles(), $fixtureFile);
+    $phpcsFile->ruleset->setSniffProperty(
+      'VariableAnalysis\Sniffs\CodeAnalysis\VariableAnalysisSniff',
+      'validUndefinedVariableNames',
+      'ignored_property'
+    );
+    $phpcsFile->process();
+    $lines = $this->getWarningLineNumbersFromFile($phpcsFile);
+    $expectedWarnings = [
+      10,
+      11,
+      22,
+      23,
+      24,
+      25
+    ];
+    $this->assertEquals($expectedWarnings, $lines);
+  }
 }

Diff for: VariableAnalysis/Tests/CodeAnalysis/fixtures/ClassReferenceFixture.php

@@ -9,6 +9,8 @@ function method_with_symbolic_ref_property() {
             $this -> $property = 'some value';
             $this->$undefined_property = 'some value';
             $this -> $undefined_property = 'some value';
+            $this->$ignored_property = 'some value';
+            $this -> $ignored_property = 'some value';
         }
     }
 
@@ -19,6 +21,8 @@ function method_with_symbolic_ref_method() {
             $this -> $method();
             $this->$undefined_method();
             $this -> $undefined_method();
+            $this->$ignored_method();
+            $this -> $ignored_method();
         }
     }
 }

Diff for: VariableAnalysis/Tests/CodeAnalysis/fixtures/FunctionWithGlobalVarFixture.php

@@ -5,6 +5,7 @@ function function_with_global_var() {
 
     echo $var;
     echo $var3;
+    echo $ice_cream;
     return $var2;
 }
 
@@ -21,3 +22,10 @@ function function_with_superglobals() {
     echo "{$GLOBALS['whatever']}";
     echo "{$GLOBALS['whatever']} $var";
 }
+
+// Variables within the global scope
+$cherry = 'topping';
+$sunday = $ice_cream . 'and a ' . $cherry;
+if ( $ice_cream ) {
+    echo 'Two scoops please!';
+}