Syntax/indentation problems with Vue mode in Emacs 27 nightly

Question

I'm using vue-mode, based on mmm-mode with Emacs 27 nightly from 10/10/2019. Since that Emacs update, I don't get any indentation support in the script section of a Vue file. Try this file with emacs -q after (use-package vue):

<template>
</template>

<script lang="ts">
import * as d3 from 'd3'
  function foo() {

  }
</script>

<style>
</style>

Go into function foo at the blank line and type TAB. No indent. :-(

And indeed if you eval (syntax-ppss (point-at-bol)) at that point, it returns (0 nil 2381 nil nil nil 0 nil nil nil nil) which means it thinks the indent should be 0, not 2.

Anyone have any idea what changed recently that could cause this? Or any ideas for how I can debug it?

Answer 1

The problem has been reported as #99 and already fixed in master of mmm-mode, but since there is no new release, you have to install the newest mmm-mode manually, or add the missing setting to mmm-save-local-variables -- for example with use-package:

(use-package vue-mode
  :mode "\\.vue$"
  :config
  (add-to-list 'mmm-save-local-variables '(syntax-ppss-table buffer))
  )