fix(extmarks): issues with revalidating marks #28961

Problem:  Invalid marks appear to be revalidated multiple times, and
          decor is added at the old position for unpaired marks.
Solution: Avoid revalidating already valid marks, and don't use old
          position to add to decor for unpaired marks.

1 files changed, 9 insertions, 2 deletions

diff --git a/src/nvim/extmark.c b/src/nvim/extmark.c
index 3236590010..4e47fa76fe 100644
--- a/src/nvim/extmark.c
+++ b/src/nvim/extmark.c
@@ -117,9 +117,16 @@ static void extmark_setraw(buf_T *buf, uint64_t mark, int row, colnr_T col, bool
   MarkTreeIter itr[1] = { 0 };
   MTKey key = marktree_lookup(buf->b_marktree, mark, itr);
   if (key.pos.row < 0 || (key.pos.row == row && key.pos.col == col)) {
+    // Does this hold? If it doesn't, we should still revalidate.
+    assert(!invalid || !mt_invalid(key));
     return;
   }
 
+  // Key already revalidated(how?) Avoid adding to decor again.
+  if (invalid && !mt_invalid(key)) {
+    invalid = false;
+  }
+
   // Only the position before undo needs to be redrawn here,
   // as the position after undo should be marked as changed.
   if (!invalid && mt_decor_any(key) && key.pos.row != row) {
@@ -140,8 +147,8 @@ static void extmark_setraw(buf_T *buf, uint64_t mark, int row, colnr_T col, bool
   marktree_move(buf->b_marktree, itr, row, col);
 
   if (invalid) {
-    MTPos end = marktree_get_altpos(buf->b_marktree, key, NULL);
-    buf_put_decor(buf, mt_decor(key), row, end.row);
+    row2 = mt_paired(key) ? marktree_get_altpos(buf->b_marktree, key, NULL).row : row;
+    buf_put_decor(buf, mt_decor(key), row, row2);
   } else if (key.flags & MT_FLAG_DECOR_SIGNTEXT && buf->b_signcols.autom) {
     buf_signcols_count_range(buf, row1, row2, 0, kNone);
   }