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https://issues.apache.org/jira/browse/EL-8?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12521491
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Jamie Taylor commented on EL-8:
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I had always intended the patch and unit test for inclusion. I thought
slapping the Apache license at the top of each file would be sufficient. In
any case, yes, it's intended to be licensed to the ASF.
I don't have to code for the patch from function-binding.txt on this machine
(at work right now), but I might be able to give you an idea of what it's
doing. Since function invocations can live arbitrarily deep in the syntax
tree, the only way to find them all is to recurse through the tree. This is
what your patch did not do, so it failed on an example where the function call
was nested inside another function call. Rather than try to recurse through
the tree externally, my patch adds a method to the nodes in the syntax tree.
The result is another syntax tree, with the function invocation nodes replaced
by "bound" function invocation nodes.
It's a lot of code, spread out over several files... but it should be easy to
follow. I suggest starting at Expression.bindFunctions. It looks like the
patch also has some stuff in there that wasn't strictly necessary - like having
run the eclipse "organize imports" on everything.
> [el] Implementation of parseExpression does not implement spec
> --------------------------------------------------------------
>
> Key: EL-8
> URL: https://issues.apache.org/jira/browse/EL-8
> Project: Commons EL
> Issue Type: Bug
> Affects Versions: 1.0
> Environment: Operating System: All
> Platform: All
> Reporter: Jamie Taylor
> Fix For: 1.1
>
> Attachments: EL-8.patch, function-binding.txt,
> TestFunctionBinding.java, TestFunctionBinding.java
>
>
> The implementation of parseExpression in the EL expression evaluator does not
> conform to the JSP 2.0 specification. The javadoc for the fMapper argument
> states that
> "The ExpressionEvaluatormustnotholdontotheFunctionMapperreferenceafter
> returning fromparseExpression(). TheExpression object returned must invoke
> the same functions regardless of whether the mappings in the
> providedFunctionMapper instance change between calling
> ExpressionEvaluator.parseExpression() andExpression.evaluate()."
> The test case which I will attach clearly shows that this is not the case.
> Why hasn't anybody noticed this before, you may ask? I suspect that the
> current implementation of Tomcat never updates the bindings in its function
> mapper once one is constructed, since the functions are defined at web-app
> load time and can't be updated after that.
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