Need some help migrating luasnip config from nvim-cmp to blink.cmp

[jannes-io]

Hi everyone, so far I'm really liking the visual and performance benefits of blink.cmp vs nvim-cmp. There's just one really annoying thing that prevents me from enjoying it fully. Which is tab behavior for luasnip that keeps on jumping back even though I've already "broken" the snippet's flow.

Behavior:

Details

Given a lua snippet with placeholders:

s('pubf', {
    t('public '),
    t('function '),
    i(1),
    t('('),
    i(2),
    t(')'),
    i(3),
    t({ '', '{', '' }),
    t('    '),
    i(4),
    t({ '', '}' }),
})

If I use this snippet, it generates:

public function |()
{

}

(where | is cursor in input mode).

If I then type a name, and break out of the snippet cycle,

public function hello()
{
    |
}

(where | is cursor in input mode).

And I press tab again, it jumps back up to the next placeholder

public function hello(|)
{
    
}

While I expect (and my nvim-cmp config did this as well):

public function hello()
{
        |
}

In nvim-cmp I had the following configuration for luasnip:

      cmp.setup {
        snippet = {
          expand = function(args)
            luasnip.lsp_expand(args.body)
          end,
        },
        completion = { completeopt = 'menu,menuone,noinsert' },
        mapping = cmp.mapping.preset.insert {
          ['<Tab>'] = cmp.mapping.confirm { select = true },
          ['<C-Space>'] = cmp.mapping.complete {},
          ['<C-l>'] = cmp.mapping(function()
            if luasnip.expand_or_locally_jumpable() then
              luasnip.expand_or_jump()
            end
          end, { 'i', 's' }),
          ['<C-h>'] = cmp.mapping(function()
            if luasnip.locally_jumpable(-1) then
              luasnip.jump(-1)
            end
          end, { 'i', 's' }),
        },
        sources = {
          {
            name = 'lazydev',
            group_index = 0,
          },
          { name = 'nvim_lsp' },
          { name = 'nvim_lsp_signature_help' },
          { name = 'luasnip' },
          { name = 'path' },
        },
      }
    end,
  },

Can anyone help me with migrating this behavior to blink.cmp? My current setup there is:

{ -- Autocompletion
    'saghen/blink.cmp',
    event = 'VimEnter',
    version = '1.*',
    dependencies = {
      'L3MON4D3/LuaSnip',
      'folke/lazydev.nvim',
    },
    opts = {
      keymap = {
        preset = 'super-tab',
      },

      appearance = {
        nerd_font_variant = 'mono',
      },

      completion = {
        documentation = { auto_show = false, auto_show_delay_ms = 250 },
      },

      sources = {
        default = { 'lsp', 'path', 'snippets', 'lazydev' },
        providers = {
          lazydev = { module = 'lazydev.integrations.blink', score_offset = 100 },
        },
      },

      snippets = { preset = 'luasnip' },
      fuzzy = { implementation = 'prefer_rust_with_warning' },
      signature = { enabled = true },
    },
  }

I think it is the keybindings I had in nvim-cmp's config that allowed me to insert tab without it doing funky things.

[soifou]

How do you "break" the cycle?

blink.cmp does not handle Luasnip session (created when you expand a snippet). AFAIK, this session is destroyed only when you jump one by one and reach the last position (see exit_roots in their doc). If you need to break the cycle, like switching to normal mode, you have to manually kill the session with luasnip.unlink_current().

You can read #1805, and Luasnip issue #872 as well for some pointers. Still, I'm kinda surprised this "just works" in nvim-cmp, you're the second person mentioning that, but I can't reproduce it or find anything in their source code 😅

Anyway, if you find a workaround or any insights about how nvim-cmp handles it, please share!

[soifou]

Why not then jump through tabstops using your keymap <C-l> until you get to the wanted position? That's the usual way to work with snippets.

[jannes-io]

I have rather large snippets that have placeholders in all places, and 9/10, I don't need all to be filled. I would like to have the exact same behavior as I had before.

I guess my question really is, how can I unbind tab, and bind <C-h> and <C-l>, like I had in my old config, but in blink.cmp?

[jannes-io]

To further elaborate, that's exactly how PHPStorm (or any intellij IDE) works as well, if you have a snippet with placeholders, and at any point you leave the space by manually moving your cursor in whatever mode, it cancels the "snippet session". I've been working like that for 10+ years now, so I don't want to retrain a decade of muscle memory 😆

[soifou]

how can I unbind tab, and bind and , like I had in my old config, but in blink.cmp?

Ah got it! This is because <Tab> in the super-tab preset you're using fall backs to snippet_forward action when no completion item can be accepted. You need to override the <Tab> keybind:

opts = {
  keymap = {
    preset = 'super-tab',
    ['<Tab>'] = {
      function(cmp)
        if cmp.snippet_active() then
          return cmp.accept()
        else
          return cmp.select_and_accept()
        end
      end,
      -- 'snippet_forward',
      'fallback',
    },
  },
  -- ...
},

[jannes-io]

Perfect 🙂