vim-patch:8.2.0920: writing viminfo fails with a circular reference

Problem:    Writing viminfo fails with a circular reference.
Solution:   Use copyID to detect the cycle. (closes vim/vim#6217)
https://github.com/vim/vim/commit/5b157fe2edfdce5f77080aeac2b4a03f39eb1c1a

1 files changed, 23 insertions, 0 deletions

diff --git a/src/nvim/shada.c b/src/nvim/shada.c
index 3b08c8a184..95257fe945 100644
--- a/src/nvim/shada.c
+++ b/src/nvim/shada.c
@@ -2679,7 +2679,30 @@ static ShaDaWriteResult shada_write(ShaDaWriteDef *const sd_writer,
       switch (vartv.v_type) {
         case VAR_FUNC:
         case VAR_PARTIAL:
+          tv_clear(&vartv);
           continue;
+        case VAR_DICT:
+          {
+            dict_T *di = vartv.vval.v_dict;
+            int copyID = get_copyID();
+            if (!set_ref_in_ht(&di->dv_hashtab, copyID, NULL)
+                && copyID == di->dv_copyID) {
+              tv_clear(&vartv);
+              continue;
+            }
+            break;
+          }
+        case VAR_LIST:
+          {
+            list_T *l = vartv.vval.v_list;
+            int copyID = get_copyID();
+            if (!set_ref_in_list(l, copyID, NULL)
+                && copyID == l->lv_copyID) {
+              tv_clear(&vartv);
+              continue;
+            }
+            break;
+          }
         default:
           break;
       }