yesodweb/yesod

widgetFile does not treat the lucius file as optional, 500 error

Closed this issue · 3 comments

benjamingoldstein commented

Hey all,

I'm new to Yesod, very excited to get my project up and running.

This is a low priority issue, I'm just sharing my workaround, and hoping to join the community here.

I've read the book, and I started with a new Yesod scaffold project. The default-layout.lucius was doing some styling I didn't want, so I deleted it.

The book seems to suggest that widgetFile only takes action if the .lucius etc files exist.

From Foundation.hs:

        pc <- widgetToPageContent $ do                                                                                
            -- addStylesheet $ StaticR css_bootstrap_css                                                              
            $(widgetFile "default-layout")                                                                            
        withUrlRenderer $(hamletFile "templates/default-layout-wrapper.hamlet")

But I'm getting a 500 Internal server error when default-layout.lucius is not there.

Here is the output from stack exec -- yesod devel :

[Error#yesod-core] templates/default-layout.lucius: openFile: does not exist (No such file or directory) @(yesod-core-1.6.9-7g4SwkDmJJ261rdNBKrLzX:Yesod.Core.Class.Yesod ./Yesod/Core/Class/Yesod.hs:662:5)
[Error#yesod-core] Error handler errored out: InternalError "templates/default-layout.lucius: openFile: does not exist (No such file or directory)" @(yesod-core-1.6.9-7g4SwkDmJJ261rdNBKrLzX:Yesod.Core.Internal.Run ./Yesod/Core/Internal/Run.hs:210:21)
GET /example
  Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
  Status: 500 Internal Server Error 0.0051s

I'm running:

command -v yesod && yesod version
/Users/user/.local/bin/yesod
yesod-bin version: 1.6.0.3

Workaround:

I simply put the file back and deleted the CSS out of it, and while Firefox gives an error that it can't load that auto-generated CSS file, it doesn't 500 error any more.

I am hoping to learn something about this / hope for this to be the answer that someone is googling for in the future.

Ben

snoyberg commented

What happens if you delete the file and run stack clean?

benjamingoldstein commented

That did the trick! Sorry I didn't know this command, I'll do this when feeling superstitious before posting in future.

I'll have a hunt around for a "troubleshooting" / FAQ / "debugging tips" area on the site / wiki, and see if I can contribute back 😊

Thanks Michael!

snoyberg commented

No worries! This is a limitation/bug in Yesod, but it's one we can't work around AFAICT. It has to do with the recompilation detection in GHC, and not wanting to cause too many recompiles.

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