Josh Tynjala created FLEX-35329:
-----------------------------------
Summary: Initializing member variable/constant that is
[Deprecated] incorrectly throws extra warning
Key: FLEX-35329
URL: https://issues.apache.org/jira/browse/FLEX-35329
Project: Apache Flex
Issue Type: Bug
Components: .Unspecified - Compiler
Affects Versions: Apache Flex 4.16.0
Reporter: Josh Tynjala
Assignee: Josh Tynjala
Priority: Minor
Consider the following class:
{code:title=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";
}
}
}
{code}
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:
{code}
/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";
^
{code}
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 ).
{code}
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);
}
{code}
The declaration of a member/static variable is a QualifiedIdentifierNode
(qualified meaning that it has 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.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
