vim-patch:8.1.1061: when substitute string throws error, substitute happens anyway

Problem:    When substitute string throws error, substitute happens anyway.
Solution:   Skip substitution when aborting. (closes vim/vim#4161)
0e97b94875

src/nvim/ex_cmds.c

@@ -3831,6 +3831,12 @@ static buf_T *do_sub(exarg_T *eap, proftime_T timeout,
           sublen = vim_regsub_multi(&regmatch,
                                     sub_firstlnum - regmatch.startpos[0].lnum,
                                     sub, sub_firstline, false, p_magic, true);
+          // If getting the substitute string caused an error, don't do
+          // the replacement.
+          if (aborting()) {
+            goto skip;
+          }
+
           // Don't keep flags set by a recursive call
           subflags = subflags_save;
           if (subflags.do_count) {