[WW-5087] AliasInterceptor doesn't properly handle Parameter.Empty

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.22
• Fix Version/s: 2.5.25, 6.0.0
• Component/s: Core Interceptors
• Assignee: Yasser Zamani
• Reporter: Brian Lenz
• Created: 28/Aug/20 15:56
• Updated: 02/Nov/21 06:06
• Resolved: 17/Sep/20 11:19

Description

As I reported on the mailing list, there is a bug with AliasInterceptor not handling the Parameter.Empty that is returned from HttpParameters.get(). Since HttpParameters.get() always returns a non-null value, the Evaluated object is treated as always being defined, which results in the empty value being set incorrectly on the stack.

The bug was originally introduced here:

https://github.com/apache/struts/commit/787f2f96eb9f1bb3c8012ab42aa222ae6286a91a#diff-b7b7c87c1012088e79dcc5a7bd9e8127R168

The fix is easy; this code:

// workaround
HttpParameters contextParameters = ActionContext.getContext().getParameters();
if (null != contextParameters) {
    value = new Evaluated(contextParameters.get(name));
}

needs to be updated to:

// workaround
HttpParameters contextParameters = ActionContext.getContext().getParameters();
if (null != contextParameters) {
    Parameter param = contextParameters.get(name);
    value = new Evaluated(param.isDefined() ? param : null);
} 

This way, it ensures the Evaluated value is only defined when appropriate.

 

Issue Links

• links to: GitHub Pull Request #438
• links to: GitHub Pull Request #439