feat(compile): use nvim_create_user_command to make lazy-load commands

[wbthomason]

This is a slight performance improvement over the old style of command creation, and moves packer toward the modern Neovim APIs

Not immediately merging because I need to track down the Neovim version when nvim_create_user_command was released - if it's v0.8.0, I'll want to hold off on this change since the release was quite recent.

I could add logic to test for the function's existence and fall back to the old method if it's not present, and might. But for now, I'd prefer to avoid adding that complexity.

[lewis6991]

I think it was added in v0.6: https://github.com/neovim/neovim/pull/16752

[folke]

@wbthomason you can get completion to work for lazy loaded commands as well. Check https://github.com/folke/lazy.nvim/blob/6affae64545da6efd2940589bff8253c08bc7252/lua/lazy/core/handler.lua#L169

[wbthomason]

@folke Thanks, that's a neat trick!

[wbthomason]

I think it was added in v0.6: neovim/neovim#16752

Yeah, I think you're right. Thanks for tracking down the relevant PR; I was too lazy to try before sleeping yesterday.

[wbthomason]

Going to merge this because it hasn't seemed to cause problems on my setup with a few days of use. Please @ me if you start experiencing bugs due to this change, and I'll revert it.

[kevinhwang91]

Error in packer_compiled: ...vim/site/pack/packer/opt/packer.nvim/lua/packer/load.lua:84: Vim:E477: No ! allowed Please check your config for correctness

[wbthomason]

@kevinhwang91 Did this happen on Neovim start, or when using a particular command?

[wbthomason]

Pushed a temporary reversion in 1d8babf

[kevinhwang91]

using a particular command?

Not sure, but Flog in vim-flog with ! throw this error.

[wbthomason]

Did it happen when you just started neovim, though, or when you tried to use Flog? Or tab-complete Flog, maybe?

[kevinhwang91]

        use {
            'rbong/vim-flog', branch = 'v2',
            cmd = {'Flog', 'Flogsplit'},
            requires = 'tpope/vim-fugitive',
            config = conf('plugs.flog')
        }

Type :Flog in the command will reproduce it.

[kevinhwang91]

I found that it only throws E477 without calling PackerCompile after this PR. After calling PackerCompile, no errors anymore.

[wbthomason]

Oh, I think I know what the problem is then (because I also cannot reproduce with a recompile). I'll add a patch to load.lua, test that I can't reproduce after that, and re-merge. Thanks!

[wbthomason]

@kevinhwang91 Note also that :Flog does not support bang, so :Flog! should throw an error (per https://github.com/rbong/vim-flog/blob/master/plugin/flog.vim#L299)

This was a legitimate bug though, since :Flog alone also throws the error and should not.

[kevinhwang91]

Yes, look like the issue is caused by the synchronization between packer_compiled.lua and load.lua

[wbthomason]

Ok, feature re-merged with my fix (that I tested to remove the issue @kevinhwang91 noted - thanks for the easy reproducer)

[kevinhwang91]

It's a bit off-topic, looks like it's a core's bug.....

vim.api.nvim_create_user_command('SayHello', 'echo "Hello world!"', {bang = true})
vim.cmd('verb com SayHello')
print(vim.inspect(vim.api.nvim_parse_cmd('SayHello', {})))

I guess the bang in core is false, that's why PackerCompile can ignore E477.

[wbthomason]

No, I believe that what happened was this:

• This PR changed the logic in load from providing a format string parameter as cause.bang to cause.bang and '!' or '' because cause.bang changed type from string to boolean with the switch to the new API
• If you had updated to this PR but not recompiled, load would still get passed the string version of cause.bang - this is the key to the bug
• Lua coerces the empty string '' to true in the expression '' and '!', so '!' was always returned
• This appended the ! to commands that do not support it, like Flog, causing the E477 to be raised when those commands were used

That's why my patch fixes the issue by explicitly checking and handling the type of cause.bang.

[kevinhwang91]

I know your explanation.

The compiled file after this PR:

pcall(vim.api.nvim_create_user_command, 'Flog', function(cmdargs)
    -- print(vim.inspect(cmdargs)) -- uncomment me

          require('packer.load')({'vim-flog'}, { cmd = 'Flog', l1 = cmdargs.line1, l2 = cmdargs.line2, bang = cmdargs.bang, args = cmdargs.args, mods = cmdargs.mods }, _G.packer_plugins)
        end,
        {nargs = '*', range = true, bang = true, complete = function()
          require('packer.load')({'vim-flog'}, { cmd = 'Flog' }, _G.packer_plugins)
          vim.api.nvim_input('<space><bs><tab>')
      end})

bang = true is passed to nvim_create_user_command, but you can uncomment print(vim.inspect(cmdargs)) to inspect the result.