Bug in Freemark/Spring Support

[egervari]

I have come across a little bug (well, more of an annoyance really) where Spring does not report the true cause of the failure when a freemarker template is not parsed properly. This is a repeatable bug that I've come across at least 6 or 7 times in the last day and it can make working with Freemarker and Spring into a much frustrating endevour.

Here is a simple template that will make it fail.

<#include "/lib/rns.ftl" />

<@html title="$&#123;pageTitle&#125;>

	<@rnsTransactionListing title="$&#123;tableTitle&#125;" transactions=rnsTransactions />

</@html>

Note, you don't need this exact page to make it fail. Notice that the title attribute is missing the ending quote: "${pageTitle}

This is an easy mistake to make however, this gives the following exception:

org.springframework.context.ApplicationContextException: Cannot load FreeMarker
template for URL [core\release.transactions.page.ftl]: Did you specify
the correct template loader path?
	at org.springframework.web.servlet.view.freemarker.FreeMarkerView.initApplicationContext(FreeMarkerView.java:136)
	at org.springframework.context.support.ApplicationObjectSupport.setApplicationContext(ApplicationObjectSupport.java:79)
	at org.springframework.web.servlet.view.AbstractCachingViewResolver.loadAndConfigureView(AbstractCachingViewResolver.java:123)
	at org.springframework.web.servlet.view.AbstractCachingViewResolver.resolveViewName(AbstractCachingViewResolver.java:78)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:629)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:535)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:321)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:103)
	at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:113)
	at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:129)
	at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:61)
	at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:84)
	at com.caucho.server.cache.CacheFilterChain.doFilter(CacheFilterChain.java:211)
	at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:177)
	at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:221)
	at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:263)
	at com.caucho.server.port.TcpConnection.run(TcpConnection.java:323)
	at com.caucho.util.ThreadPool.runTasks(ThreadPool.java:430)
	at com.caucho.util.ThreadPool.run(ThreadPool.java:377)
	at java.lang.Thread.run(Thread.java:534)

I assure you, the loader path is not a problem. If one fixes the problem in the template, it will work fine. However, if I re-create the problem, this is what happens:

freemarker.core.ParseException: Encountered "{" at line 5, column 41.
Was expecting:
    "=" ...
    
	at freemarker.core.FMParser.generateParseException(FMParser.java:4411)
	at freemarker.core.FMParser.jj_consume_token(FMParser.java:4286)
	at freemarker.core.FMParser.NamedArgs(FMParser.java:1886)
	at freemarker.core.FMParser.UnifiedMacroTransform(FMParser.java:1771)
	at freemarker.core.FMParser.FreemarkerDirective(FMParser.java:2216)
	at freemarker.core.FMParser.Content(FMParser.java:2433)
	at freemarker.core.FMParser.OptionalBlock(FMParser.java:2601)
	at freemarker.core.FMParser.Root(FMParser.java:2773)
	at freemarker.template.Template.<init>&#40;Template.java&#58;144&#41;
	at freemarker.cache.TemplateCache.loadTemplate&#40;TemplateCache.java&#58;376&#41;
	at freemarker.cache.TemplateCache.getTemplate&#40;TemplateCache.java&#58;347&#41;
	at freemarker.cache.TemplateCache.getTemplate&#40;TemplateCache.java&#58;229&#41;
	at freemarker.template.Configuration.getTemplate&#40;Configuration.java&#58;426&#41;
	at freemarker.template.Configuration.getTemplate&#40;Configuration.java&#58;398&#41;
	at org.springframework.web.servlet.view.freemarker.FreeMarkerView.getTemplate&#40;FreeMarkerView.java&#58;168&#41;
	at org.springframework.web.servlet.view.freemarker.FreeMarkerView.renderMergedTemplateModel&#40;FreeMarkerView.java&#58;151&#41;
	at org.springframework.web.servlet.view.AbstractTemplateView.renderMergedOutputModel&#40;AbstractTemplateView.java&#58;160&#41;
	at org.springframework.web.servlet.view.AbstractView.render&#40;AbstractView.java&#58;238&#41;
	at org.springframework.web.servlet.DispatcherServlet.render&#40;DispatcherServlet.java&#58;644&#41;
	at org.springframework.web.servlet.DispatcherServlet.doService&#40;DispatcherServlet.java&#58;535&#41;
	at org.springframework.web.servlet.FrameworkServlet.service&#40;FrameworkServlet.java&#58;321&#41;
	at javax.servlet.http.HttpServlet.service&#40;HttpServlet.java&#58;103&#41;

As you can see, the correct exception is finally thrown. However, if I restart my server with the template problem intact, it's possible to repeat this resource-loader exception bug.

Motivation for fix? While the exceptions are working just fine if a template is already loaded, it makes debugging *new* pages while the server is running, or even old pages after a restart, very problematic. This template is trivial, however, if it were a library template with 600 lines of code, finding the bug would not be trivial. Even further, I noticed that this happens when a pages includes other templates with errors, even if the main template is syntactically correct.

Anyway, I would really appreciate it if you guys could implement a fix since I have quite a few more templates to make :P

Thanks,
Ken Egervari

[davison]

Thanks Ken. For future reference, better to log these in JIRA so they don't get lost in the forums. I've done this one..

http://opensource.atlassian.com/proj...browse/SPR-279

[davison]

Note, you don't need this exact page to make it fail. Notice that the title attribute is missing the ending quote: "${pageTitle}

This is an easy mistake to make however, this gives the following exception:

side note: there are some good FTL plugins that will show such errors up in your editor/IDE. I've used the eclipse one to good effect. http://www.freemarker.org/editors.html

[egervari]

Unfortunately I'm using IDEA and it's not supported. I still think using Freemarker without syntax highlighting is more productive and produces cleaner code than velocity, so I'll stick with it either way. Glad I could help and I'll be sure to use JIRA from now on.

Regards,
Ken