eval: Make sure that copyID is reset when needed

Works by making value pushed on stack represent the exhausted list.

Fixes #5901, except for dictionaries which need similar adjustment.

src/nvim/api/private/helpers.c

@@ -387,6 +387,8 @@ static inline void typval_encode_list_start(EncodedData *const edata,
 #define TYPVAL_ENCODE_CONV_LIST_START(tv, len) \
     typval_encode_list_start(edata, (size_t)(len))
 
+#define TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START(tv, mpsv)
+
 static inline void typval_encode_between_list_items(EncodedData *const edata)
   FUNC_ATTR_ALWAYS_INLINE FUNC_ATTR_NONNULL_ALL
 {
@@ -499,6 +501,7 @@ static inline void typval_encode_dict_end(EncodedData *const edata)
 #undef TYPVAL_ENCODE_CONV_FUNC_END
 #undef TYPVAL_ENCODE_CONV_EMPTY_LIST
 #undef TYPVAL_ENCODE_CONV_LIST_START
+#undef TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START
 #undef TYPVAL_ENCODE_CONV_EMPTY_DICT
 #undef TYPVAL_ENCODE_CONV_NIL
 #undef TYPVAL_ENCODE_CONV_BOOL

src/nvim/eval.c

@@ -19147,23 +19147,25 @@ static inline void _nothing_conv_func_end(typval_T *const tv, const int copyID)
       } \
     } while (0)
 
-static inline int _nothing_conv_list_start(typval_T *const tv)
+static inline int _nothing_conv_real_list_after_start(
+    typval_T *const tv, MPConvStackVal *const mpsv)
   FUNC_ATTR_ALWAYS_INLINE FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  if (tv == NULL) {
+  assert(tv != NULL);
-    return NOTDONE;
-  }
   tv->v_lock = VAR_UNLOCKED;
   if (tv->vval.v_list->lv_refcount > 1) {
     tv->vval.v_list->lv_refcount--;
     tv->vval.v_list = NULL;
+    mpsv->data.l.li = NULL;
     return OK;
   }
   return NOTDONE;
 }
-#define TYPVAL_ENCODE_CONV_LIST_START(tv, len) \
+#define TYPVAL_ENCODE_CONV_LIST_START(tv, len)
+
+#define TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START(tv, mpsv) \
     do { \
-      if (_nothing_conv_list_start(tv) != NOTDONE) { \
+      if (_nothing_conv_real_list_after_start(tv, &mpsv) != NOTDONE) { \
         goto typval_encode_stop_converting_one_item; \
       } \
     } while (0)
@@ -19253,6 +19255,7 @@ static inline void _nothing_conv_dict_end(typval_T *const tv,
 #undef TYPVAL_ENCODE_CONV_EMPTY_LIST
 #undef TYPVAL_ENCODE_CONV_EMPTY_DICT
 #undef TYPVAL_ENCODE_CONV_LIST_START
+#undef TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START
 #undef TYPVAL_ENCODE_CONV_LIST_BETWEEN_ITEMS
 #undef TYPVAL_ENCODE_CONV_LIST_END
 #undef TYPVAL_ENCODE_CONV_DICT_START

src/nvim/eval/encode.c

@@ -369,6 +369,8 @@ int encode_read_from_list(ListReaderState *const state, char *const buf,
 #define TYPVAL_ENCODE_CONV_LIST_START(tv, len) \
     ga_append(gap, '[')
 
+#define TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START(tv, mpsv)
+
 #define TYPVAL_ENCODE_CONV_EMPTY_DICT(tv, dict) \
     ga_concat(gap, "{}")
 
@@ -789,6 +791,7 @@ bool encode_check_json_key(const typval_T *const tv)
 #undef TYPVAL_ENCODE_CONV_FUNC_END
 #undef TYPVAL_ENCODE_CONV_EMPTY_LIST
 #undef TYPVAL_ENCODE_CONV_LIST_START
+#undef TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START
 #undef TYPVAL_ENCODE_CONV_EMPTY_DICT
 #undef TYPVAL_ENCODE_CONV_NIL
 #undef TYPVAL_ENCODE_CONV_BOOL
@@ -933,6 +936,8 @@ char *encode_tv2json(typval_T *tv, size_t *len)
 #define TYPVAL_ENCODE_CONV_LIST_START(tv, len) \
     msgpack_pack_array(packer, (size_t)(len))
 
+#define TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START(tv, mpsv)
+
 #define TYPVAL_ENCODE_CONV_EMPTY_DICT(tv, dict) \
     msgpack_pack_map(packer, 0)
 
@@ -994,6 +999,7 @@ char *encode_tv2json(typval_T *tv, size_t *len)
 #undef TYPVAL_ENCODE_CONV_FUNC_END
 #undef TYPVAL_ENCODE_CONV_EMPTY_LIST
 #undef TYPVAL_ENCODE_CONV_LIST_START
+#undef TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START
 #undef TYPVAL_ENCODE_CONV_EMPTY_DICT
 #undef TYPVAL_ENCODE_CONV_NIL
 #undef TYPVAL_ENCODE_CONV_BOOL

src/nvim/eval/typval_encode.c.h

@@ -129,6 +129,16 @@
 ///             point to a special dictionary.
 /// @param  len  List length. Is an expression which evaluates to an integer.
 
+/// @def TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START
+/// @brief Macros used after pushing list onto the stack
+///
+/// Only used for real list_T* lists, not for special dictionaries or partial
+/// arguments.
+///
+/// @param  tv  Pointer to typval where value is stored. May be NULL. May
+///             point to a special dictionary.
+/// @param  mpsv  Pushed MPConvStackVal value.
+
 /// @def TYPVAL_ENCODE_CONV_LIST_BETWEEN_ITEMS
 /// @brief Macros used after finishing converting non-last list item
 ///
@@ -354,6 +364,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
           },
         },
       }));
+      TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START(tv, _mp_last(*mpstack));
       break;
     }
     case VAR_SPECIAL: {