From dadaa7fcade459ebd1fef2ee4eada1a389ea036d Mon Sep 17 00:00:00 2001
From: Sean Dewar <6256228+seandewar@users.noreply.github.com>
Date: Sat, 22 Aug 2026 15:19:16 +0100
Subject: [PATCH] fix(ui2): offset extmarks copied to pager by srow #41425

Problem: wrong end_row when copying extmarks to the pager buffer when expanding
a message. Results in incorrect highlights or errors such as "invalid `end_col`
out of range".

Solution: don't forget to offset end_row by srow, as is already done for the
copied lines and extmark rows.
---
 runtime/lua/vim/_core/ui2/messages.lua |  3 +-
 test/functional/ui/messages2_spec.lua  | 40 ++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/runtime/lua/vim/_core/ui2/messages.lua b/runtime/lua/vim/_core/ui2/messages.lua
index 9178b7857f..2421647a81 100644
--- a/runtime/lua/vim/_core/ui2/messages.lua
+++ b/runtime/lua/vim/_core/ui2/messages.lua
@@ -239,7 +239,8 @@ function M.expand_msg(src, tgt, focus)
 
     api.nvim_buf_set_lines(ui.bufs[tgt], srow, -1, false, lines)
     for _, m in ipairs(marks) do
-      hlopts.hl_group, hlopts.end_col, hlopts.end_row = m[4].hl_group, m[4].end_col, m[4].end_row
+      hlopts.hl_group, hlopts.end_col, hlopts.end_row =
+        m[4].hl_group, m[4].end_col, srow + m[4].end_row
       api.nvim_buf_set_extmark(ui.bufs[tgt], ui.ns, srow + m[2], m[3], hlopts)
     end
   else
diff --git a/test/functional/ui/messages2_spec.lua b/test/functional/ui/messages2_spec.lua
index bb867306b9..306cdc324e 100644
--- a/test/functional/ui/messages2_spec.lua
+++ b/test/functional/ui/messages2_spec.lua
@@ -1346,4 +1346,44 @@ describe('messages2', function()
     end)
     screen:expect_unchanged()
   end)
+
+  it('correct end_row for highlights copied to pager #41419', function()
+    command('echo "a" | echo "b"') -- Two lines; end_row should be offset by 2
+    screen:expect([[
+      ^                                                     |
+      {1:~                                                    }|*10
+      {3:                                                     }|
+      a                                                    |
+      b                                                    |
+    ]])
+    feed('g<lt>')
+    screen:expect([[
+                                                           |
+      {1:~                                                    }|*9
+      {3:                                                     }|
+      ^a                                                    |
+      b                                                    |
+                                                           |
+    ]])
+    command('echohl WarningMsg | echo "c" | echohl ErrorMsg | echo "de"')
+    screen:expect([[
+                                                           |
+      {1:~                                                    }|*7
+      {3:                                                     }|
+      ^a                                                    |
+      b                                                    |
+      {19:c}                                                    |
+      {9:de}                                                   |
+                                                           |
+    ]])
+    feed('g<lt>')
+    screen:expect([[
+                                                           |
+      {1:~                                                    }|*9
+      {3:                                                     }|
+      {19:^c}                                                    |
+      {9:de}                                                   |
+                                                           |
+    ]])
+  end)
 end)