Add test for template partial rendering with a local variable.

[ajcollins]

Hi Mark,

After reading the documentation on partial rendering (https://gobuffalo.io/en/docs/partials#local-context) I expected local and global variables to be merged. This doesn't seem to happen at present. That may be the desired behaviour?

This adds a failing test case. It could be combined with the existing test case, depending on your preferred approach.

I've created a candidate fix in plush/compiler.go for which I'll submit an MR for review.

Best wishes,

Alex

[markbates]

I think the correct fix is here in the buffalo repo, instead of the plush repo, since the partial helper is defined in buffalo. https://github.com/gobuffalo/buffalo/blob/master/render/template.go#L43

[ajcollins]

That was what I'd originally hoped, but I couldn't see an elegant way for the partial helper to access the required data: since plush is responsible for binding the arguments to the function call, and already attempts to supply missing args for global context.

How do you feel if the exec call storing a local of the old data and a copy of the current data in the templateRenderer. Calls to partial would then merge supplied data before calling exec? each exec would then restore the old data before returning.

[markbates]

I think you need to start here https://github.com/gobuffalo/buffalo/blob/master/render/template.go#L29 capture the original Data and hold onto it in the struct. Then in partial you would want to create a new map that merges the renderer Data and the partial's data.

[ajcollins]

Snap! I'll do that then - thanks.

[ajcollins]

Note that whilst this passes the test as written, I'm seeing "missing parameters" errors when using the path helpers in a buffalo app. I'll need to investigate this further.