Copy strictMath flag in temporary env for mixin definitions

Fixes an unreleased regression from fe66a9a (If4a0a7ce05),
which broke the elliptical corner feature of CSS border-radius,
which includes a literal slash (not meant as math).

https://developer.mozilla.org/en-US/docs/Web/CSS/border-radius

The upstream handles creating new environment by calling
context.Eval() which calls copyFromOriginal() function.
This function preserves set of properties, including
`strictMath` param.

Whe we initialize the temporary env, we should preserve
at least the `strictMath`, the best approach is to
utilize the copyEvalEnv() method from Environment that
would create a copy of Environemnt with preserved
`strictMath` param.

The upstream tests run with `{strictMath: true}`, therefore
we should run tests in the same way. This allows us to remove
some overrides.

Bug: T362343
Change-Id: I1b2ec0ae206a49bf4fdf01f2acd47534343f3ba1

lib/Less/Environment.php

@@ -97,6 +97,7 @@ public function isFileParsed( $file ) {
 	public function copyEvalEnv( $frames = [] ) {
 		$new_env = new self();
 		$new_env->frames = $frames;
+		$new_env->strictMath = $this->strictMath;
 		return $new_env;
 	}
 

lib/Less/Tree/Mixin/Definition.php

@@ -44,6 +44,7 @@ public function toCSS() {
 	}
 
 	/**
+	 * @param Less_Environment $env
 	 * @see less-2.5.3.js#Definition.prototype.evalParams
 	 */
 	public function compileParams( $env, $mixinFrames, $args = [], &$evaldArguments = [] ) {
@@ -104,8 +105,7 @@ public function compileParams( $env, $mixinFrames, $args = [], &$evaldArguments
 					} elseif ( isset( $param['value'] ) ) {
 
 						if ( !$mixinEnv ) {
-							$mixinEnv = new Less_Environment();
-							$mixinEnv->frames = array_merge( [ $frame ], $mixinFrames );
+							$mixinEnv = $env->copyEvalEnv( array_merge( [ $frame ], $mixinFrames ) );
 						}
 
 						$val = $param['value']->compile( $mixinEnv );
@@ -140,6 +140,12 @@ public function compile( $env ) {
 		return new self( $this->name, $this->params, $this->rules, $this->condition, $this->variadic, $env->frames );
 	}
 
+	/**
+	 * @param Less_Environment $env
+	 * @param array|null $args
+	 * @param bool|null $important
+	 * @return Less_Tree_Ruleset
+	 */
 	public function evalCall( $env, $args = null, $important = null ) {
 		Less_Environment::$mixin_stack++;
 
@@ -159,8 +165,7 @@ public function evalCall( $env, $args = null, $important = null ) {
 		$ruleset = new Less_Tree_Ruleset( null, $this->rules );
 		$ruleset->originalRuleset = $this->ruleset_id;
 
-		$ruleSetEnv = new Less_Environment();
-		$ruleSetEnv->frames = array_merge( [ $this, $frame ], $mixinFrames );
+		$ruleSetEnv = $env->copyEvalEnv( array_merge( [ $this, $frame ], $mixinFrames ) );
 		$ruleset = $ruleset->compile( $ruleSetEnv );
 
 		if ( $important ) {
@@ -172,7 +177,11 @@ public function evalCall( $env, $args = null, $important = null ) {
 		return $ruleset;
 	}
 
-	/** @return bool */
+	/**
+	 * @param array $args
+	 * @param Less_Environment $env
+	 * @return bool
+	 */
 	public function matchCondition( $args, $env ) {
 		if ( !$this->condition ) {
 			return true;
@@ -185,13 +194,13 @@ public function matchCondition( $args, $env ) {
 
 		$frame = $this->compileParams( $env, array_merge( $this->frames, $env->frames ), $args );
 
-		$compile_env = new Less_Environment();
-		$compile_env->frames = array_merge(
+		$compile_env = $env->copyEvalEnv(
+			array_merge(
 				[ $frame ], // the parameter variables
-				 $this->frames, // the parent namespace/mixin frames
-				 $env->frames		// the current environment frames
-			);
-
+				$this->frames, // the parent namespace/mixin frames
+				$env->frames // the current environment frames
+			)
+		);
 		$compile_env->functions = $env->functions;
 
 		return (bool)$this->condition->compile( $compile_env );

test/fixtures.php

@@ -38,6 +38,9 @@
 			'javascript',
 			'plugin',
 		],
+		'options' => [
+			'strictMath' => true
+		]
 	],
 	'lessjs-2.5.3/compression' => [
 		'lessDir' => "$fixtureDir/lessjs-2.5.3/less/compression",

test/phpunit/FixturesTest.php

@@ -23,7 +23,6 @@ class phpunit_FixturesTest extends phpunit_bootstrap {
 			'parens' => true,
 
 			// Temporary disabled
-			'css' => true, // T352911 & T352866
 			'mixins-guards' => true, // T352867
 			'urls' => true, // T353147
 			'variables' => true, // T352830, T352866