Dottydoc crashes when upgrading liqp to 0.7.2

[smarter]

Dottydoc currently uses liqp 0.6.7, when upgrading to 0.7.2 (see branch https://github.com/dotty-staging/dotty/commits/upgrade/liqp-0.7.2) and running genDocs we get:

java.lang.ArrayIndexOutOfBoundsException: 1
        at scala.collection.mutable.WrappedArray$ofRef.apply(WrappedArray.scala:130)
        at dotty.tools.dottydoc.staticsite.tags$RenderTitle.render(tags.scala:189)
        at dotty.tools.dottydoc.staticsite.tags$RenderTitle.render(tags.scala:166)
        at liqp.nodes.TagNode.render(TagNode.java:32)
        at liqp.tags.For.renderArray(For.java:112)
        at liqp.tags.For.render(For.java:56)
        at liqp.nodes.TagNode.render(TagNode.java:32)
        at liqp.nodes.BlockNode.render(BlockNode.java:38)
        at liqp.Template$1.call(Template.java:266)
        ... 5 more

The crash happens here: https://github.com/lampepfl/dotty/blob/517ba8cbd7c4c0cd5058a4dd1bdfce2c0fe441cf/doc-tool/src/dotty/tools/dottydoc/staticsite/tags.scala#L189 maybe @felixmulder can give some context on what this does? :)

[felixmulder]

Looks like functionality to implement a custom tag like:

{ renderTitle | "someArg" }

[felixmulder]

Yes, the syntax in my previous response was wrong - but the sentiment the same. It's using liqp to add some custom tags to the markup language.

It tries to get the arguments from "nodes" but I guess there has been some changes to liqp

[felixmulder]

I'd say most likely someone is calling the tag with the wrong number of args - or liqp changed in some unexpected way

[smarter]

Apparently all params are parsed as one string now: bkiers/Liqp#46, I'll try to make a PR.

[felixmulder]

Interesting, I wonder what prompted that changerge.

[smarter]

Apparently it's to conform with the spec of Liquid.

[smarter]

Alright, I give up for now, in 0.7.2 when we want to handle {% renderRef member.alias %}, we get just the string "member.alias" and there's no way to automatically parse that, so you have to split on ".", lookup "member" in the context, then "alias" in the resulting map, that's super annoying to do and probably not even correct if the grammar of the language allows more complicated things. We should open an issue against liqp I think. (EDIT: bkiers/Liqp#70)

[bkiers]

Interesting, I wonder what prompted that changerge.
...
Apparently it's to conform with the spec of Liquid.

True: it's the specs of Liquid that say all parameters to tags are to be treated as a single string. Me implementing them as expressions was wrong.

... and there's no way to automatically parse that

No need to parse it; evaluating is all that's needed. I posted a possible workaround how to evaluate the string/expression member.alias: bkiers/Liqp#70

[nicolasstucki]

@abgruszecki is this issue still relevant?

[smarter]

The new scaladoc still uses liqp and it's still an old version so I'd say yes: https://github.com/lampepfl/dotty/blob/3d85473ee9706b00882f2a1419575b8f0d88487e/project/Build.scala#L1486 /cc @romanowski