feat(hipatterns)!: make default highlighting be more visible

Make them reverse and bold of diagnostic groups instead of directly
linking to them.

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 - FEATURE: implement `yank_path` mapping to yank full path under cursor.
 
+## mini.hipatterns
+
+- BREAKING FEATURE: make `MiniHipatterns{Fixme,Hack,Todo,Note}` highlight groups by default be inverse and bold variant of `Diagnostic{Error,Warn,Info,Hint}` group instead of directly link to it. This ensures better visibility for color schemes which don't have explicit support for 'mini.hipatterns'.
+
 ## mini.hues
 
 - FEATURE: add `'lowmedium'` and `'mediumhigh'` saturation levels.

lua/mini/hipatterns.lua

@@ -704,12 +704,20 @@ H.create_autocommands = function()
   au('ColorScheme', '*', H.on_colorscheme, 'Reload all enabled pattern highlighters')
 end
 
---stylua: ignore
 H.create_default_hl = function()
-  vim.api.nvim_set_hl(0, 'MiniHipatternsFixme', { default = true, link = 'DiagnosticError' })
-  vim.api.nvim_set_hl(0, 'MiniHipatternsHack',  { default = true, link = 'DiagnosticWarn' })
-  vim.api.nvim_set_hl(0, 'MiniHipatternsTodo',  { default = true, link = 'DiagnosticInfo' })
-  vim.api.nvim_set_hl(0, 'MiniHipatternsNote',  { default = true, link = 'DiagnosticHint' })
+  local get_hl_data = vim.fn.has('nvim-0.9') == 1
+      and function(x) return vim.api.nvim_get_hl(0, { name = x, link = false }) end
+    or function(x) return vim.api.nvim_get_hl_by_name(x, true) end
+  local hi_link_bold_reverse = function(to, from)
+    local data = get_hl_data(from)
+    data.default, data.bold, data.reverse = true, true, true
+    data.cterm = { bold = true, reverse = true }
+    vim.api.nvim_set_hl(0, to, data)
+  end
+  hi_link_bold_reverse('MiniHipatternsFixme', 'DiagnosticError')
+  hi_link_bold_reverse('MiniHipatternsHack', 'DiagnosticWarn')
+  hi_link_bold_reverse('MiniHipatternsTodo', 'DiagnosticInfo')
+  hi_link_bold_reverse('MiniHipatternsNote', 'DiagnosticHint')
 end
 
 H.is_disabled = function(buf_id)

tests/test_hipatterns.lua

@@ -89,11 +89,18 @@ T['setup()']['creates side effects'] = function()
 
   -- Highlight groups
   child.cmd('hi clear')
+  child.cmd('hi DiagnosticError guifg=#ff0000 ctermfg=9')
+  child.cmd('hi DiagnosticWarn  guifg=#ffff00 ctermfg=11')
+  child.cmd('hi DiagnosticInfo  guifg=#0000ff ctermfg=14')
+  child.cmd('hi DiagnosticHint  guifg=#00ffff ctermfg=12')
   load_module()
-  expect.match(child.cmd_capture('hi MiniHipatternsFixme'), 'links to DiagnosticError')
-  expect.match(child.cmd_capture('hi MiniHipatternsHack'), 'links to DiagnosticWarn')
-  expect.match(child.cmd_capture('hi MiniHipatternsTodo'), 'links to DiagnosticInfo')
-  expect.match(child.cmd_capture('hi MiniHipatternsNote'), 'links to DiagnosticHint')
+  local has_highlight = function(group, value) expect.match(child.cmd_capture('hi ' .. group), value) end
+  if child.fn.has('nvim-0.9') == 0 then MiniTest.skip('Neovim<0.9 does not preserve `ctermfg`, which is fine.') end
+
+  has_highlight('MiniHipatternsFixme', 'cterm=bold,reverse ctermfg=9 gui=bold,reverse guifg=#ff0000')
+  has_highlight('MiniHipatternsHack', 'cterm=bold,reverse ctermfg=11 gui=bold,reverse guifg=#ffff00')
+  has_highlight('MiniHipatternsTodo', 'cterm=bold,reverse ctermfg=14 gui=bold,reverse guifg=#0000ff')
+  has_highlight('MiniHipatternsNote', 'cterm=bold,reverse ctermfg=12 gui=bold,reverse guifg=#00ffff')
 end
 
 T['setup()']['creates `config` field'] = function()
@@ -129,7 +136,7 @@ end
 T['setup()']['ensures colors'] = function()
   load_module()
   child.cmd('colorscheme default')
-  expect.match(child.cmd_capture('hi MiniHipatternsFixme'), 'links to DiagnosticError')
+  expect.match(child.cmd_capture('hi MiniHipatternsFixme'), 'gui=bold,reverse')
 end
 
 T['Auto enable'] = new_set()