fix(nvim): keep grep match bg on preview target line

lua/fff/location_utils.lua

@@ -1,5 +1,7 @@
 local M = {}
 
+local set_cursor_line_mark
+
 --- Jump to a location in the current buffer
 --- @param location table|nil Location data from search results
 function M.jump_to_location(location)
@@ -51,11 +53,12 @@ function M.highlight_location(bufnr, location, namespace)
       local line_content = vim.api.nvim_buf_get_lines(bufnr, target_line - 1, target_line, false)[1] or ''
       local end_col = math.min(target_col + 1, #line_content)
 
+      local line_ok, line_mark_id = set_cursor_line_mark(bufnr, namespace, target_line - 1)
+      if line_ok then table.insert(extmarks, { id = line_mark_id, line = target_line - 1 }) end
+
       local ok, mark_id = pcall(vim.api.nvim_buf_set_extmark, bufnr, namespace, target_line - 1, target_col, {
         end_col = end_col,
         hl_group = 'IncSearch', -- inc search are better visible for a single chars
-        line_hl_group = 'CursorLine',
-        number_hl_group = 'CursorLineNr',
         priority = 1000,
       })
 
@@ -82,11 +85,12 @@ function M.highlight_location(bufnr, location, namespace)
         local line_content = vim.api.nvim_buf_get_lines(bufnr, start_line - 1, start_line, false)[1] or ''
         end_col = math.min(end_col, #line_content)
 
+        local line_ok, line_mark_id = set_cursor_line_mark(bufnr, namespace, start_line - 1)
+        if line_ok then table.insert(extmarks, { id = line_mark_id, line = start_line - 1 }) end
+
         local ok, mark_id = pcall(vim.api.nvim_buf_set_extmark, bufnr, namespace, start_line - 1, start_col, {
           end_col = end_col,
           hl_group = 'IncSearch',
-          line_hl_group = 'CursorLine',
-          number_hl_group = 'CursorLineNr',
           priority = 1000,
         })
 
@@ -162,11 +166,7 @@ function M.highlight_grep_matches(bufnr, location, namespace)
   -- line stays styled until it scrolls out of view.
   if location.line then
     local target_line = math.max(1, math.min(location.line, line_count))
-    local ok, mark_id = pcall(vim.api.nvim_buf_set_extmark, bufnr, namespace, target_line - 1, 0, {
-      line_hl_group = 'CursorLine',
-      number_hl_group = 'CursorLineNr',
-      priority = 999,
-    })
+    local ok, mark_id = set_cursor_line_mark(bufnr, namespace, target_line - 1)
     if ok then table.insert(extmarks, { id = mark_id, line = target_line - 1 }) end
   end
 
@@ -305,4 +305,21 @@ function M.format_location(location)
   return ''
 end
 
+--- Pin a row with a full-width CursorLine range, above syntax but below matches
+--- (`line_hl_group` bg would override every `hl_group` bg regardless of priority)
+--- @param bufnr number Buffer number
+--- @param namespace number Namespace for extmarks
+--- @param row number 0-based row to highlight
+--- @return boolean ok, number|string mark_id_or_err pcall result of nvim_buf_set_extmark
+set_cursor_line_mark = function(bufnr, namespace, row)
+  return pcall(vim.api.nvim_buf_set_extmark, bufnr, namespace, row, 0, {
+    end_row = row + 1,
+    end_col = 0,
+    hl_eol = true,
+    hl_group = 'CursorLine',
+    number_hl_group = 'CursorLineNr',
+    priority = 999,
+  })
+end
+
 return M

tests/location_utils_spec.lua

@@ -0,0 +1,76 @@
+---@diagnostic disable: undefined-field, need-check-nil
+local location_utils = require('fff.location_utils')
+
+--- Collect extmarks grouped by hl_group, asserting none use line_hl_group
+--- @param buf number Buffer number
+--- @param ns number Namespace to read extmarks from
+--- @return table<string, table[]> marks Marks keyed by hl_group with row, col and details
+local function marks_by_group(buf, ns)
+  local by_group = {}
+  for _, mark in ipairs(vim.api.nvim_buf_get_extmarks(buf, ns, 0, -1, { details = true })) do
+    local details = mark[4]
+    assert.is_nil(details.line_hl_group)
+    if details.hl_group then
+      by_group[details.hl_group] = by_group[details.hl_group] or {}
+      table.insert(by_group[details.hl_group], { row = mark[2], col = mark[3], details = details })
+    end
+  end
+  return by_group
+end
+
+--- Assert a single full-width CursorLine mark on row, with lower priority than every match
+--- @param marks table<string, table[]> Result of marks_by_group
+--- @param match_group string Highlight group of the match marks
+--- @param row number 0-based row expected to carry the CursorLine mark
+local function assert_cursor_line_below(marks, match_group, row)
+  local cursor_line = marks.CursorLine[1]
+  assert.are.equal(1, #marks.CursorLine)
+  assert.are.equal(row, cursor_line.row)
+  assert.are.equal(0, cursor_line.col)
+  assert.are.equal(row + 1, cursor_line.details.end_row)
+  assert.is_true(cursor_line.details.hl_eol)
+  assert.are.equal('CursorLineNr', cursor_line.details.number_hl_group)
+
+  for _, match in ipairs(marks[match_group]) do
+    assert.is_true(match.details.priority > cursor_line.details.priority)
+  end
+end
+
+describe('location_utils highlight', function()
+  local buf, ns
+
+  before_each(function()
+    buf = vim.api.nvim_create_buf(false, true)
+    ns = vim.api.nvim_create_namespace('fff_location_utils_spec')
+    vim.api.nvim_buf_set_lines(buf, 0, -1, false, { 'hello world', 'abc hello x' })
+  end)
+
+  after_each(function() vim.api.nvim_buf_delete(buf, { force = true }) end)
+
+  it('keeps fuzzy grep matches above the pinned cursor line', function()
+    location_utils.highlight_location(buf, { grep_query = 'hlo', line = 2, fuzzy_match_ranges = { { 4, 9 } } }, ns)
+    local marks = marks_by_group(buf, ns)
+    local grep_hl = require('fff.conf').get().hl.grep_match or 'IncSearch'
+
+    assert.are.equal(1, #marks[grep_hl])
+    assert.are.equal(4, marks[grep_hl][1].col)
+    assert_cursor_line_below(marks, grep_hl, 1)
+  end)
+
+  it('keeps line:col highlight above the cursor line', function()
+    location_utils.highlight_location(buf, { line = 2, col = 5 }, ns)
+    local marks = marks_by_group(buf, ns)
+
+    assert.are.equal(4, marks.IncSearch[1].col)
+    assert_cursor_line_below(marks, 'IncSearch', 1)
+  end)
+
+  it('keeps single line range highlight above the cursor line', function()
+    location_utils.highlight_location(buf, { start = { line = 1, col = 1 }, ['end'] = { line = 1, col = 6 } }, ns)
+    local marks = marks_by_group(buf, ns)
+
+    assert.are.equal(0, marks.IncSearch[1].col)
+    assert.are.equal(5, marks.IncSearch[1].details.end_col)
+    assert_cursor_line_below(marks, 'IncSearch', 0)
+  end)
+end)