Add option to use diagnostic signs

[hermitmaster]

Can this functionality be implemented utilising API?
nvim-tree exposes extensive API (see :h nvim-tree-api). Can it be used to achieve your goal? Is there a missing API that would make it possible?
Given stable status of nvim-tree it's preferred to add new API than new functionality.

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like

  use({
    'nvim-tree/nvim-tree.lua',
    requires = 'nvim-tree/nvim-web-devicons',
    config = function()
      require('nvim-tree').setup({
        diagnostics = {
          enable = true,
          -- This is the additional option I'm proposing
          use_diagnostic_signs = true,
          on_dirs = true,
        },
      })
    end,
  })

Describe alternatives you've considered

  use({
    'nvim-tree/nvim-tree.lua',
    requires = 'nvim-tree/nvim-web-devicons',
    config = function()
      require('nvim-tree').setup({
        diagnostics = {
          enable = true,
          icons = {
            error = vim.fn.sign_getdefined('DiagnosticSignError')[1].text,
            hint = vim.fn.sign_getdefined('DiagnosticSignHint')[1].text,
            info = vim.fn.sign_getdefined('DiagnosticSignInfo')[1].text,
            warning = vim.fn.sign_getdefined('DiagnosticSignWarn')[1].text,
          },
        },
      })
    end,
  })

Additional context
I think this is probably the common scenario. Most folks want to share the diagnostic signs across plugins related to LSP. I'd be happy to open a PR for this if it is determined to be valuable.

[alex-courtis]

To confirm your proposal: this is a change to the diagnostics icons/glyphs, not diagnostics itself.

This is a good idea. We should use the string|table pattern, something like:

    *nvim-tree.diagnostics.icons*
    Icons for diagnostic severity.
    Set to `"DiagnosticSign"` to use signs defined as per |diagnostic-signs|,
    falling back to defaults when sign is not defined.
      Type: `table` | `string`, Default: `{ hint = "", info = "", warning = "", error = "" }`

Fallback shouldn't be a drama.

[hermitmaster]

That is what I was proposing. 👍

[alex-courtis]

FIELD_OVERRIDE_TYPECHECK has reached a point where disambiguation is a problem.

Please update the keys to contain full paths in the user's options.

I would be most grateful if you could apply the same to FIELD_SKIP_VALIDATE.

[alex-courtis]

See nvim-lualine/lualine.nvim#1091

[gegoune]

I would even argue so that should become default value. Users set up diagnostics and expect them to propagate throughout editor. I certainly set nvim-tree's diagnostic to the same characters.

[alex-courtis]

I would even argue so that should become default value. Users set up diagnostics and expect them to propagate throughout editor. I certainly set nvim-tree's diagnostic to the same characters.

Defaults, yes please.

I've already applied the standard groups for diagnostic highlighting: https://github.com/nvim-tree/nvim-tree.lua/pull/2455/files#diff-16d5e714e01617fa3906fbcf68963baeb235dde81bc9fd2e7a5ba95526765e18R112

[alex-courtis]

DiagnosticSign* aren't nvim standard or built in signs.

Highlight groups are defined in plugins like https://github.com/echasnovski/mini.base16/tree/main and used by lualine etc. if they are present.

The lualine PR above hasn't been merged; it's still using the same mechanism as nvim-tree.

This is possible following #2415 - we can simply use any pre-defined signs:

nvim-tree.lua/lua/nvim-tree/renderer/decorator/init.lua

Line 96 in 8857c79

function Decorator:define_sign(icon)