Handle syntax without syntax or indent files

A syntax in the config without a syntax file, like postcss, showed
E484 on opening a file. Skip loading it, with a warning in debug.

A syntax without an indent file used cindent, which broke indent of
languages like pug, stylus without their plugins, or toml. Keep the
indent instead. Lines outside blocks still use cindent.

autoload/vue.vim

@@ -263,6 +263,10 @@ endfunction
 " Load all syntax files in 'runtimepath'
 " Useful if there is no default syntax file provided by vim
 function! vue#LoadFullSyntax(group, syntax)
+  if empty(globpath(&runtimepath, 'syntax/'.a:syntax.'.vim'))
+    call vue#Warn(a:syntax.': syntax not found in runtimepath')
+    return
+  endif
   call vue#Log(a:syntax.': load full')
   call s:SetCurrentSyntax(a:syntax)
   execute 'syntax include '.a:group.' syntax/'.a:syntax.'.vim'

indent/vue.vim

@@ -75,6 +75,11 @@ function! s:GetBlockIndent(syntax)
   let indentexpr = get(s:indent, syntax) 
   if !empty(indentexpr)
     let ind = eval(indentexpr)
+  elseif has_key(s:indent, syntax)
+    " No indent file for syntax in config, keep indent as cindent may break
+    " languages like pug or toml
+    call vue#LogWithLnum('indentexpr not found for '.syntax.', keep indent')
+    let ind = -1
   else
     call vue#LogWithLnum('indentexpr not found for '.syntax.', use cindent')
     let ind = cindent(v:lnum)

test/cases/no-syntax-indent-file.vim

@@ -0,0 +1,15 @@
+" postcss has no syntax or indent file, toml has no indent file. They have
+" their blocks and keep indent
+let g:vim_vue_plugin_config = {
+      \'syntax': {
+      \   'template': ['html'],
+      \   'style': ['css', 'postcss'],
+      \   'i18n': ['toml'],
+      \},
+      \}
+
+function! Check()
+  call ExpectBlock('color: blue', 'style', 'postcss', 'postcssStyleBlock')
+  call ExpectBlock('hello', 'i18n', 'toml', 'tomlI18nBlock')
+  call ExpectIndentEachLine()
+endfunction

test/cases/no-syntax-indent-file.vue

@@ -0,0 +1,15 @@
+<template>
+  <div>x</div>
+</template>
+
+<style lang="postcss">
+p
+  color: red
+  a
+    color: blue
+</style>
+
+<i18n lang="toml">
+[en]
+  hello = "hi"
+</i18n>

test/run.vim

@@ -92,7 +92,8 @@ function! ExpectTag(lnum, tag)
 endfunction
 
 " Call GetVueIndent() for each non-blank line from line 2 as when typing it,
-" which shows errors hidden by 'indentexpr', and check the indent
+" which shows errors hidden by 'indentexpr', and check the indent. -1 keeps
+" the indent
 function! ExpectIndentEachLine()
   for lnum in range(2, line('$'))
     if getline(lnum) =~ '^\s*$'
@@ -101,7 +102,8 @@ function! ExpectIndentEachLine()
     call cursor(lnum, 1)
     let v:lnum = lnum
     try
-      call ExpectEqual(GetVueIndent(), indent(lnum),
+      let ind = GetVueIndent()
+      call ExpectEqual(ind == -1 ? indent(lnum) : ind, indent(lnum),
             \ printf('GetVueIndent() at line %d', lnum))
     catch
       call Fail(printf('GetVueIndent() at line %d: %s', lnum, v:exception))