Details
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Bug
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Status: Open
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Major
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Resolution: Unresolved
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2.3.14
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None
Description
I am using velocity to render results page. During performance optimizations I noticed significant memory usage from com.opensymphony.xwork2.ognl.OgnlUtil#compile. There is caching implemented in OgnlUtil, but if expression compilation fails, it is not cached.
I am not really sure if this problem is in struts or velocity engine. But situation is following:
- In velocity template trying to render string <p>$!foo</p>
- If value is null, velocity calls org.apache.velocity.runtime.parser.node.ASTReference#getNullString
- Internally there is call to context.get(".literal." + nullString)
- And this ".literal." expression always reaches OgnlUtil#compile and compilation fails.
Below is stacktrace for more details:
at com.opensymphony.xwork2.ognl.OgnlUtil.compile(OgnlUtil.java:248) at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:236) at com.opensymphony.xwork2.ognl.OgnlValueStack.getValueUsingOgnl(OgnlValueStack.java:291) at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValue(OgnlValueStack.java:274) at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValueWhenExpressionIsNotNull(OgnlValueStack.java:256) at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:236) at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:298) at org.apache.struts2.dispatcher.StrutsRequestWrapper.getAttribute(StrutsRequestWrapper.java:82) at org.apache.velocity.tools.view.context.ChainedContext.getAttribute(Unknown Source:-1) at org.apache.velocity.tools.view.context.ChainedContext.internalGet(Unknown Source:-1) at org.apache.velocity.context.AbstractContext.get(AbstractContext.java:193) at org.apache.velocity.context.InternalContextAdapterImpl.get(InternalContextAdapterImpl.java:267) at org.apache.velocity.runtime.parser.node.ASTReference.getNullString(ASTReference.java:510) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:465) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.apache.velocity.runtime.parser.node.ASTStringLiteral.value(ASTStringLiteral.java:330) at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:71) at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:142) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.apache.velocity.runtime.directive.Parse.render(Parse.java:260) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.apache.velocity.Template.merge(Template.java:356) at org.apache.velocity.Template.merge(Template.java:260) at org.apache.struts2.dispatcher.VelocityResult.doExecute(VelocityResult.java:156) at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
