Implement isVisble for Less_Tree_Anonymous

We have made the nodeVisible property to be slightly different than that of less.js.

Less.js defaults to null but we can't default to null because we don't have a full implementation of the visibility feature.

So for now we would just assume that all nodes defaults to true and implement the full visibility feature in a later task.

Bug: T393383
Change-Id: I5b203b24fd208781a25b3551be535263464eeb57

Author: anny21

lib/Less/Tree.php

@@ -11,6 +11,14 @@ class Less_Tree {
 	public $extendOnEveryPath;
 	/** @var Less_Tree_Extend[] */
 	public $allExtends;
+	/**
+	 * This is set to true to ensure visibility
+	 * for all except Less_Tree_Anonymous where we decide
+	 * if the the node should be visible or not
+	 *
+	 * @var bool
+	 */
+	public $nodeVisible = true;
 
 	/**
 	 * @var Less_Parser
@@ -201,4 +209,11 @@ public static function __set_state( $args ) {
 		return $obj;
 	}
 
+	/**
+	 * @see less-3.13.1.js#Node.prototype.isVisible
+	 */
+	public function isVisible() {
+		return $this->nodeVisible;
+	}
+
 }

lib/Less/Tree/Anonymous.php

@@ -59,9 +59,8 @@ public function isRulesetLike() {
 	 * @see less-3.13.1.js#Anonymous.prototype.genCSS
 	 */
 	public function genCSS( $output ) {
-		// TODO: When we implement $visibilityInfo, store this result in-class
-		$nodeVisible = $this->value !== "" && $this->value !== 0;
-		if ( $nodeVisible ) {
+		$this->nodeVisible = $this->value !== "" && $this->value !== 0;
+		if ( $this->nodeVisible ) {
 			$output->add( $this->value, $this->currentFileInfo, $this->index, $this->mapLines );
 		}
 	}

lib/Less/Tree/Ruleset.php

@@ -582,7 +582,7 @@ public function genCSS( $output ) {
 
 			Less_Environment::$lastRule = $currentLastRule;
 
-			if ( !Less_Environment::$lastRule ) {
+			if ( !Less_Environment::$lastRule && $rule->isVisible() ) {
 				$output->add( $tabRuleStr );
 			} else {
 				Less_Environment::$lastRule = false;