[jira] [Commented] (FREEMARKER-48) When custom fremarker method throws exception, it is impossible to find line/row where called

["Daniel Dekany (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FREEMARKER-48?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15941645#comment-15941645 ] 

Daniel Dekany commented on FREEMARKER-48:
-----------------------------------------

As far as I see, the idea was that `TemplateMethodModelEx.exec` shouldn't throw anything but `TemplateModelException`. If other exception is thrown inside the implementation of `exec`, you are supposed to catch it and rethrow it wrapped into a `TemplateModelException`. Then it will automatically carry the FreeMarker-specific location information, because `TemplateException`-s can do that (plain exceptions can't).

Of course, while the Java forces you to do the above for checked exceptions, it's easy to forget about the unchecked ones. So certainly it would have been better if FreeMarker catches exceptions that you haven't wrapped into `TemplateModelException`, and wraps them into `TemplateModelException` itself. Heck, maybe `exec` should have been allowed to throw any kind of checked `Exception`, and then we catch and wrap them. But now doing so is not backward compatible. Maybe we can add a configuration option to catch the unchecked exceptions though. (BTW, we have the same problem with `foo[bar]`.) We will see in 2.3.27.

> When custom fremarker method throws exception, it is impossible to find line/row where called
> ---------------------------------------------------------------------------------------------
>
>                 Key: FREEMARKER-48
>                 URL: https://issues.apache.org/jira/browse/FREEMARKER-48
>             Project: Apache Freemarker
>          Issue Type: Bug
>          Components: engine
>    Affects Versions: 2.3.25-incubating
>         Environment: Any
>            Reporter: Vojtech Knyttl
>
> Consider this stacktrace:
> https://gist.github.com/knyttl/dba8f94b9736eb2751074c34dce7b467
> On line `DispatcherServlet.renderView(DispatcherServlet.java:308)` I have started freemarker to render a template. During that process it uses custom method (`HrefMethod.exec(HrefMethod.java:28)`), but this method threw an exception. However Freemarker does not report a line/row of the template where this method was called making it very hard for debug.
> I would be happy if `freemarker.core.MethodCall._eval(MethodCall.java:65)` had some try-catch blcok, that in case of an exception would add lines/rows/details of the element that caused the exception.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)