1 files changed, 19 insertions, 10 deletions
diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index ac3cf959c8..d964da371a 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -22,7 +22,6 @@
 #include "nvim/memory.h"
 #include "nvim/message.h"
 #include "nvim/misc1.h"
-#include "nvim/misc2.h"
 #include "nvim/garray.h"
 #include "nvim/move.h"
 #include "nvim/option.h"
@@ -166,7 +165,7 @@ bool hasFoldingWin(
   int use_level = FALSE;
   int maybe_small = FALSE;
   garray_T    *gap;
-  int low_level = 0;;
+  int low_level = 0;
 
   checkupdate(win);
   /*
@@ -762,16 +761,12 @@ void clearFolding(win_T *win)
  */
 void foldUpdate(win_T *wp, linenr_T top, linenr_T bot)
 {
-  if (compl_busy) {
-    return;
-  }
-
-  fold_T      *fp;
-  if (wp->w_buffer->terminal) {
+  if (compl_busy || State & INSERT) {
     return;
   }
 
   // Mark all folds from top to bot as maybe-small.
+  fold_T *fp;
   (void)foldFind(&wp->w_folds, top, &fp);
   while (fp < (fold_T *)wp->w_folds.ga_data + wp->w_folds.ga_len
          && fp->fd_top < bot) {
@@ -793,6 +788,19 @@ void foldUpdate(win_T *wp, linenr_T top, linenr_T bot)
   }
 }
 
+/// Updates folds when leaving insert-mode.
+void foldUpdateAfterInsert(void)
+{
+  if (foldmethodIsManual(curwin)  // foldmethod=manual: No need to update.
+      // These foldmethods are too slow, do not auto-update on insert-leave.
+      || foldmethodIsSyntax(curwin) || foldmethodIsExpr(curwin)) {
+    return;
+  }
+
+  foldUpdateAll(curwin);
+  foldOpenCursor();
+}
+
 /* foldUpdateAll() {{{2 */
 /*
  * Update all lines in a window for folding.
@@ -1600,7 +1608,7 @@ static void foldAddMarker(linenr_T lnum, char_u *marker, size_t markerlen)
       STRLCPY(newline + line_len, marker, markerlen + 1);
     else {
       STRCPY(newline + line_len, cms);
-      STRNCPY(newline + line_len + (p - cms), marker, markerlen);
+      memcpy(newline + line_len + (p - cms), marker, markerlen);
       STRCPY(newline + line_len + (p - cms) + markerlen, p + 2);
     }
 
@@ -1665,7 +1673,8 @@ static void foldDelMarker(linenr_T lnum, char_u *marker, size_t markerlen)
     if (u_save(lnum - 1, lnum + 1) == OK) {
       /* Make new line: text-before-marker + text-after-marker */
       newline = xmalloc(STRLEN(line) - len + 1);
-      STRNCPY(newline, line, p - line);
+      assert(p >= line);
+      memcpy(newline, line, (size_t)(p - line));
       STRCPY(newline + (p - line), p + len);
       ml_replace(lnum, newline, FALSE);
     }