fix(range): handle inclusive/exclusive positions on multibyte characters

runtime/lua/vim/range.lua

@@ -150,11 +150,12 @@ end
 ---@param buf integer
 ---@return integer, integer
 local function to_inclusive_pos(buf, row, col)
+  local line = get_line(buf, row)
   if col > 0 then
-    col = col - 1
+    col = col + vim.str_utf_start(line, col) - 1
   elseif col == 0 and row > 0 then
     row = row - 1
-    col = #get_line(buf, row)
+    col = #line > 0 and #line + vim.str_utf_start(line, #line) - 1 or 0
   end
 
   return row, col
@@ -165,11 +166,12 @@ end
 ---@param buf integer
 ---@return integer, integer
 local function to_exclusive_pos(buf, row, col)
-  if col >= #get_line(buf, row) then
+  local line = get_line(buf, row)
+  if col >= #line then
     row = row + 1
     col = 0
   else
-    col = col + 1
+    col = col + vim.str_utf_end(line, col + 1) + 1
   end
 
   return row, col
@@ -179,7 +181,7 @@ end
 ---@param r1 vim.Range
 ---@param r2 vim.Range
 function M.__lt(r1, r2)
-  if r1:is_empty() then
+  if r1:is_empty() or r2:is_empty() then
     return cmp_pos(r1[3], r1[4], r2[1], r2[2]) ~= 1
   end
 
@@ -191,7 +193,7 @@ end
 ---@param r1 vim.Range
 ---@param r2 vim.Range
 function M.__le(r1, r2)
-  if r1:is_empty() then
+  if r1:is_empty() or r2:is_empty() then
     return cmp_pos(r1[3], r1[4], r2[1], r2[2]) ~= 1
   end
 

test/functional/lua/range_spec.lua

@@ -80,6 +80,18 @@ describe('vim.range', function()
     }, range)
   end)
 
+  it('converts between inclusive mark ranges ending on multibyte characters', function()
+    insert('🙂')
+
+    local range, mark_range = exec_lua(function()
+      vim.o.selection = 'inclusive'
+      local range = vim.range.mark(0, 1, 0, 1, 0)
+      return { range[1], range[2], range[3], range[4] }, { range:to_mark() }
+    end)
+    eq({ 0, 0, 0, 4 }, range)
+    eq({ 1, 0, 1, 0 }, mark_range)
+  end)
+
   it('checks whether a range contains a position', function()
     eq(
       true,