Breakpoint symbol is not using sign column background color by default

[shmerl]

Steps to Reproduce

My color scheme defines one color for Normal and a different color for SignColumn.

When simply placing a breakpoint, it uses background color of the editor pane (Normal) rather than sign column (SignColumn) color.

See example below (note background around symbol B):

Expected Result

It would make sense for the breakpoint and other nvim-dap signs to use the background of SignColumn by default.

Actual Result

Color used for breakpoint signs matches Normal color of the scheme.

I can work around it by setting the matching color for SignColumn through configuration for DapBreakpoint, DapStopped and etc. but it's not ideal and would break every time the color schema is changed.

[shmerl]

I can try fixing it, but would appreciate if you can please give any pointers where in the code the color is being set (or not set).

Thanks!

[shmerl]

If anyone needs also, for the current code, here is a workaround that reads current color for SignColumn and reuses it. This has to be applied before color scheme is loaded for the first time (or you can reload the color scheme if plugin is lazy loaded for example and this snippet is only executed at some later point):

vim.api.nvim_create_autocmd("ColorScheme", {
  pattern = "*",
  desc = "Prevent colorscheme clearing self-defined DAP marker colors",
  callback = function()
      -- Reuse current SignColumn background (except for DapStoppedLine)
      local sign_column_hl = vim.api.nvim_get_hl(0, { name = 'SignColumn' })
      -- if bg or ctermbg aren't found, use bg = 'bg' (which means current Normal) and ctermbg = 'Black'
      -- convert to 6 digit hex value starting with #
      local sign_column_bg = (sign_column_hl.bg ~= nil) and ('#%06x'):format(sign_column_hl.bg) or 'bg'
      local sign_column_ctermbg = (sign_column_hl.ctermbg ~= nil) and sign_column_hl.ctermbg or 'Black'

      vim.api.nvim_set_hl(0, 'DapStopped', { fg = '#00ff00', bg = sign_column_bg, ctermbg = sign_column_ctermbg })
      vim.api.nvim_set_hl(0, 'DapStoppedLine', { bg = '#2e4d3d', ctermbg = 'Green' })
      vim.api.nvim_set_hl(0, 'DapBreakpoint', { fg = '#c23127', bg = sign_column_bg, ctermbg = sign_column_ctermbg })
      vim.api.nvim_set_hl(0, 'DapBreakpointRejected', { fg = '#888ca6', bg = sign_column_bg, ctermbg = sign_column_ctermbg })
      vim.api.nvim_set_hl(0, 'DapLogPoint', { fg = '#61afef', bg = sign_column_bg, ctermbg = sign_column_ctermbg })
  end
})

-- reload current color scheme to pick up colors override if it was set up in a lazy plugin definition fashion
vim.cmd.colorscheme(vim.g.colors_name)

[mfussenegger]

nvim-dap doesn't define the background at all for the signs.

It is just:

DapBreakpoint = { text = "B", texthl = "", linehl = "", numhl = "" },

[shmerl]

Well, somehow with my theme it turned to Normal instead of staying what was already defined, so there is some disconnect there. I assume numhl being set to "" turns it to default (Normal) may be? Using the above workaround ensures that theme defined value is used.

[shmerl]

OK, this fixes the bug in your code itself (i.e. setting texthl = "SignColumn" for your signs except for DapStoppedLine):

local signs = {
  DapBreakpoint = { text = "B", texthl = "SignColumn", linehl = "", numhl = "" },
  DapBreakpointCondition = { text = "C", texthl = "SignColumn", linehl = "", numhl = "" },
  DapBreakpointRejected = { text = 'R', texthl = 'SignColumn', linehl = '', numhl = '' },
  DapLogPoint = { text = 'L', texthl = 'SignColumn', linehl = '', numhl = '' },
  DapStopped = { text = '→', texthl = 'SignColumn', linehl = 'debugPC', numhl = '' },
}

Somehow setting texthl to empty doesn't use current value but simply falls back to Normal which is not correct.

It doesn't hurt for your code to do that since you are intending not to change the coloring of the sign column by default, right? Though may be it's working around a bug in neovim itself.

[shmerl]

Thanks for fixing it on your side.