fix(operators): make all operators work with empty textobject/motion

Details:
- Nothing is done for built-in operators (like `y` or `d`) in case
  textobject/motion mapping does literally nothing.
  Similar is reasonable to expect from 'mini.operators' operators.

Resolve #2165

Author: echasnovski

lua/mini/operators.lua

@@ -331,6 +331,7 @@ MiniOperators.evaluate = function(mode)
 
   local evaluate_func = H.get_config().evaluate.func or MiniOperators.default_evaluate_func
   local data = H.get_region_data(mode)
+  if data == nil then return end
   data.reindent_linewise = true
   H.apply_content_func(evaluate_func, data)
 end
@@ -365,12 +366,14 @@ MiniOperators.exchange = function(mode)
   if not H.exchange_has_step_one() then
     -- Store data about first region
     H.cache.exchange.step_one = H.exchange_set_region_extmark(mode, true)
+    if H.cache.exchange.step_one == nil then return end
 
     -- Temporarily remap `<C-c>` to stop the exchange
     H.exchange_set_stop_mapping()
   else
     -- Store data about second region
     H.cache.exchange.step_two = H.exchange_set_region_extmark(mode, false)
+    if H.cache.exchange.step_two == nil then return end
 
     -- Do exchange
     H.exchange_do()
@@ -414,6 +417,7 @@ MiniOperators.multiply = function(mode)
 
   local count = mode == 'visual' and vim.v.count1 or H.cache.multiply.count
   local data = H.get_region_data(mode)
+  if data == nil then return end
   local mark_from, mark_to, submode = data.mark_from, data.mark_to, data.submode
 
   H.with_temp_context({ registers = { 'x', '"' } }, function()
@@ -475,6 +479,7 @@ MiniOperators.replace = function(mode)
   local count = mode == 'visual' and vim.v.count1 or H.cache.replace.count
   local register = mode == 'visual' and vim.v.register or H.cache.replace.register
   local data = H.get_region_data(mode)
+  if data == nil then return '' end
   data.count = count
   data.register = register
   data.reindent_linewise = H.get_config().replace.reindent_linewise
@@ -854,6 +859,7 @@ H.exchange_set_region_extmark = function(mode, add_highlight)
 
   -- Compute regular marks for target region
   local region_data = H.get_region_data(mode)
+  if region_data == nil then return end
   local submode = region_data.submode
   local markcoords_from, markcoords_to = H.get_mark(region_data.mark_from), H.get_mark(region_data.mark_to)
 
@@ -1111,6 +1117,7 @@ end
 
 -- General --------------------------------------------------------------------
 H.apply_content_func = function(content_func, data)
+  if data == nil then return end
   local mark_from, mark_to, submode = data.mark_from, data.mark_to, data.submode
   local reindent_linewise = data.reindent_linewise
 
@@ -1186,6 +1193,11 @@ H.get_region_data = function(mode)
   local mark_from = selection_is_visual and '<' or '['
   local mark_to = selection_is_visual and '>' or ']'
 
+  -- Detect empty region. NOTE: This doesn't work when cursor is on first line
+  -- and first column, but there doesn't seem to be a better way to do that.
+  local pos_from, pos_to = H.get_mark(mark_from), H.get_mark(mark_to)
+  if pos_to[1] < pos_from[1] or (pos_to[1] == pos_from[1] and pos_to[2] < pos_from[2]) then return end
+
   return { mode = mode, submode = submode, mark_from = mark_from, mark_to = mark_to }
 end
 

tests/test_operators.lua

@@ -467,6 +467,15 @@ T['Evaluate']['works in Normal mode for line'] = function()
   validate_edit({ '1 + 1', '1 + 2' }, { 1, 0 }, { 'g==', 'j', '.' }, { '2', '3' }, { 2, 0 })
 end
 
+T['Evaluate']['works with empty textobject/motion'] = function()
+  child.api.nvim_set_keymap('o', 'w', '<Cmd><CR>', {})
+  child.lua('_G.x = 1')
+  set_lines({ 'xxx' })
+  set_cursor(1, 1)
+  type_keys('g=', 'w')
+  eq(get_lines(), { 'xxx' })
+end
+
 T['Evaluate']['works in Visual mode'] = function()
   -- Charwise
   validate_edit({ '1 + 1 = (1 + 1)' }, { 1, 8 }, { 'va)', 'g=' }, { '1 + 1 = 2' }, { 1, 8 })
@@ -805,6 +814,31 @@ T['Exchange']['works with `[count]` in Normal mode for line'] = function()
   )
 end
 
+T['Exchange']['works with empty textobject/motion'] = function()
+  child.api.nvim_set_keymap('o', 'w', '<Cmd><CR>', {})
+
+  -- On step one
+  set_lines({ 'xxx', 'yyy' })
+  set_cursor(1, 1)
+  type_keys('gx', 'w')
+  eq(child.fn.maparg('<C-c>'), '')
+  -- - Should ignore previous time and treat this as step one
+  type_keys('j', 'gx', '$')
+  eq(get_lines(), { 'xxx', 'yyy' })
+  type_keys('k', 'gx', '$')
+  eq(get_lines(), { 'xyy', 'yxx' })
+
+  -- On step two
+  set_lines({ 'xxx', 'yyy' })
+  set_cursor(1, 1)
+  type_keys('gx', 'iw')
+  -- - Should ignore this one while still allowing proper step two
+  type_keys('jl', 'gx', 'w')
+  eq(get_lines(), { 'xxx', 'yyy' })
+  type_keys('gx', '$')
+  eq(get_lines(), { 'yy', 'yxxx' })
+end
+
 T['Exchange']['works in Visual mode'] = function()
   -- Charwise from - Charwise to
   validate_edit1d('aa bb', 0, { 'viwgx', 'w', 'viwgx' }, 'bb aa', 3)
@@ -1366,6 +1400,14 @@ T['Multiply']['works with `cmdheight=0`'] = function()
   child.expect_screenshot({ redraw = false })
 end
 
+T['Multiply']['works with empty textobject/motion'] = function()
+  child.api.nvim_set_keymap('o', 'w', '<Cmd><CR>', {})
+  set_lines({ 'xxx' })
+  set_cursor(1, 1)
+  type_keys('gm', 'w')
+  eq(get_lines(), { 'xxx' })
+end
+
 T['Multiply']['works in Visual mode'] = function()
   validate_edit1d('aa bb', 0, { 'viw', 'gm' }, 'aaaa bb', 2)
 
@@ -1786,6 +1828,15 @@ T['Replace']['works with `[count]` in Normal mode for line'] = function()
   )
 end
 
+T['Replace']['works with empty textobject/motion'] = function()
+  child.api.nvim_set_keymap('o', 'w', '<Cmd><CR>', {})
+  set_lines({ 'xxx', 'yyy' })
+  set_cursor(1, 1)
+  type_keys('yiw', 'jl')
+  type_keys('gr', 'w')
+  eq(get_lines(), { 'xxx', 'yyy' })
+end
+
 T['Replace']['works in Visual mode'] = function()
   -- Charwise selection
   validate_edit({ 'aa bb' }, { 1, 0 }, { 'yiw', 'w', 'viw', 'gr' }, { 'aa aa' }, { 1, 3 })
@@ -2184,6 +2235,14 @@ T['Sort']['works in Normal mode for line'] = function()
   validate_edit({ 't, r, s', 'c, a, b' }, { 1, 0 }, { 'gss', 'j', '.' }, { 'r, s, t', 'a, b, c' }, { 2, 0 })
 end
 
+T['Sort']['works with empty textobject/motion'] = function()
+  child.api.nvim_set_keymap('o', 'w', '<Cmd><CR>', {})
+  set_lines({ 'fedcba' })
+  set_cursor(1, 1)
+  type_keys('gs', 'w')
+  eq(get_lines(), { 'fedcba' })
+end
+
 T['Sort']['works in Visual mode'] = function()
   -- Charwise region
   validate_edit1d('c, a, b', 0, { 'v$', 'gs' }, 'a, b, c', 0)