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  1. Apache Flex
  2. FLEX-35329

Initializing member variable/constant that is [Deprecated] incorrectly throws extra warning

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      Description

      Consider the following class:

      Deprecated.as
      package
      {
      	import flash.display.Sprite;
      
      	public class Deprecated extends Sprite
      	{
      		[Deprecated]
      		public static var STATIC_DEPRECATED:String = "static";
      
      		[Deprecated]
      		public static var STATIC_DEPRECATED2:String;
      
      		[Deprecated]
      		public var memberDeprecated:String = "member";
      
      		[Deprecated]
      		public var memberDeprecated2:String;
      
      		public function Deprecated()
      		{
      			STATIC_DEPRECATED = "new value";
      			Deprecated.STATIC_DEPRECATED = "new value";
      			memberDeprecated = "new value";
      			this.memberDeprecated = "new value";
      			STATIC_DEPRECATED2 = "new value";
      			Deprecated.STATIC_DEPRECATED2 = "new value";
      			memberDeprecated2 = "new value";
      			this.memberDeprecated2 = "new value";
      		}
      	}	
      }
      

      The compiler should give eight warnings for each of the lines in the constructor. However, it actually gives 10 warnings. Here are the two extra warnings:

      /Users/joshtynjala/Desktop/Deprecated/src/Deprecated.as(8): col: 21 Warning: 'STATIC_DEPRECATED' has been deprecated.
      
      		public static var STATIC_DEPRECATED:String = "static";
      		                  ^
      
      /Users/joshtynjala/Desktop/Deprecated/src/Deprecated.as(14): col: 14 Warning: 'memberDeprecated' has been deprecated.
      
      		public var memberDeprecated:String = "member";
      		           ^
      

      Notice that there are no warnings for STATIC_DEPRECATED2 and memberDeprecated2 because they are not initialized. It's only when a member or static variable is initialized that the warnings are shown. It appears that when the compiler checks for usage of deprecated variables is a little too aggressive.

      The Falcon compiler and Adobe's ASC 2.0 compiler do not give these same extra warnings. They only give a warning on actual usage.

      These warnings make it difficult to deprecate a constant or another variable in an open source library. It makes compile-time noisy with a lot of warnings that need to be ignored.

      Note: When compiling with a library in SWC form, the compiler does not show these warnings. I suspect that this is why this was never really encountered with the Flex framework, since the SWCs are pre-compiled. However, for many open source libraries, developers often simply use the source code with the -source-path compiler option instead of a pre-compiled SWC. That's when these warnings can be seen. As a long-time library developer, I never used [Deprecated] metadata because of this bug.

      Solution, which I will implement:

      In LintEvaluator, modify evaluate( Context cx, SetExpressionNode node ).

      if (slot != null && !(node.expr instanceof QualifiedIdentifierNode))
      {
      	//if it's a qualified identifier node, then it's a member/static
      	//variable on a class that is being initialized, like this:
      	//public var memberVar:String = "hi";
      	//this case should not have a warning!
      	checkDeprecatedSlot(cx, node.expr, node.ref, slot);
      }
      

      The declaration of a member/static variable is a QualifiedIdentifierNode (qualified meaning that it may have modifiers like public/private, static, etc.), but actual usage will be an IdentifierNode instead. So, if it's a QualifiedIdentifierNode, we know that we don't need to check if the variable is deprecated or not.

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            • Assignee:
              joshtynjala Josh Tynjala
              Reporter:
              joshtynjala Josh Tynjala
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              • Created:
                Updated:
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