fix(messages): better formatting for ext_messages #31839

Problem:  Message grid newline formatting based on `msg_col` is not
          utilized with ext_messages.
Solution: Increment `msg_col` with the cell width of the chunk. Allowing
          message code that uses `msg_col` to determine when to place a
          newline to do so. E.g. when the message goes beyond `Columns`;
          this is not necessarily where the ext_messages implementation
          would want to place a newline, but it is a best guess. Message
          parsing and manipulation is still possible.

1 files changed, 16 insertions, 1 deletions

diff --git a/test/functional/ui/messages_spec.lua b/test/functional/ui/messages_spec.lua
index 1e51652c4f..77ffc475b0 100644
--- a/test/functional/ui/messages_spec.lua
+++ b/test/functional/ui/messages_spec.lua
@@ -1121,7 +1121,7 @@ stack traceback:
     ]],
       messages = {
         {
-          content = { { 'wildmenu  wildmode' } },
+          content = { { 'wildmenu  wildmode\n' } },
           history = false,
           kind = 'wildlist',
         },
@@ -1335,6 +1335,21 @@ stack traceback:
     feed('i')
     n.assert_alive()
   end)
+
+  it(':digraph contains newlines', function()
+    command('digraph')
+    screen:expect({
+      condition = function()
+        local nl = 0
+        eq('list_cmd', screen.messages[1].kind)
+        for _, chunk in ipairs(screen.messages[1].content) do
+          nl = nl + (chunk[2]:find('\n') and 1 or 0)
+        end
+        eq(682, nl)
+        screen.messages = {}
+      end,
+    })
+  end)
 end)
 
 describe('ui/builtin messages', function()