setpos() updates the wrong logical Visual mark - #21023

Thanks, but that visual marks are clamped is not correct I think. Take the following test:

diff --git a/src/testdir/test_visual.vim b/src/testdir/test_visual.vim
index beea4c431..f2e7a1489 100644
--- a/src/testdir/test_visual.vim
+++ b/src/testdir/test_visual.vim
@@ -3065,4 +3065,14 @@ func Test_visual_ended_in_unloaded_buffer()
   %bw!
 endfunc

+func Test_visual_clamp()
+  new
+  call setline(1, ['one', 'two', 'three'])
+  normal! 2GVjy
+  call setpos("'>", [0, 1, 1, 0])
+  '<,'>d
+  call assert_equal(['three'], getline(1,'$'))
+  bw!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

clamping here means after setting the '> mark both visual marks point to line 1 and we suddenly lost the original visual selection, which means we are deleting an unexpected range. That is too much surprising and I think we should not do this.

Is there a reason we need to do the clamping on setting the mark? I believe we don't need to do it and leave it to getmark() to return the marks in the correct order.

You're right. Your example exposed a bug in the clamping logic: moving '> before '< discarded the previous endpoint. I removed the clamping. setpos() now resolves the requested logical mark and updates only that endpoint, while getmark() handles the ordering.

I added your linewise case and the inverse crossing case; both now preserve the full range.

I found an existing compatibility constraint while testing the revised approach. Consider a reversed stored selection with endpoints 7,1:

• setpos("\x27<", 2) followed by setpos("\x27>", 8) would ideally produce logical range 2..8.
• Existing custom text objects also replace both endpoints consecutively. Moving the same selection wholly right (setpos("\x27<", 8), then setpos("\x27>", 10)) must produce 8..10.

After the first call, both cases are reversed stored endpoints followed by setting \x27> beyond the high endpoint. Without tracking call history, choosing the logical endpoint preserves the first case but breaks the existing pair-replacement behavior; choosing the stored endpoint does the reverse.

Which behavior should take precedence when a call crosses the old range? I can keep this fix limited to non-crossing updates (the original report), or make logical endpoint naming take precedence across crossings.