shada: Set the unnamed register to the previous unnamed register on startup

runtime/autoload/shada.vim

@@ -45,7 +45,7 @@ call map(copy(s:SHADA_ENTRY_NAMES),
 let s:SHADA_MAP_ENTRIES = {
   \'search_pattern': ['sp', 'sh', 'ss', 'sb', 'sm', 'sc', 'sl', 'se', 'so',
   \                   'su'],
-  \'register': ['n', 'rc', 'rw', 'rt'],
+  \'register': ['n', 'rc', 'rw', 'rt', 'ru'],
   \'global_mark': ['n', 'f', 'l', 'c'],
   \'local_mark': ['f', 'n', 'l', 'c'],
   \'jump': ['f', 'l', 'c'],
@@ -139,6 +139,7 @@ let s:SHADA_STANDARD_KEYS = {
   \'rt': ['type', 'regtype', s:SHADA_ENUMS.regtype.CHARACTERWISE],
   \'rw': ['block width', 'uint', 0],
   \'rc': ['contents', 'binarray', s:SHADA_REQUIRED],
+  \'ru': ['is_unnamed', 'boolean', g:msgpack#false],
   \'n':  ['name', 'intchar', char2nr('"')],
   \'l':  ['line number', 'uint', 1],
   \'c':  ['column', 'uint', 0],

runtime/doc/starting.txt

@@ -1296,6 +1296,9 @@ exactly four MessagePack objects:
                                                    line should be represented
                                                    as NL according to
                                                    |NL-used-for-Nul|.
+                       ru   Boolean          false Unnamed register. Whether
+                                                   the unnamed register had
+                                                   pointed to this register.
                        n    UInteger         N/A   Register name: character
                                                    code in range [1, 255].
                                                    Example: |quote0| register

src/nvim/ops.c

@@ -5780,7 +5780,7 @@ static inline bool reg_empty(const yankreg_T *const reg)
 /// @return Pointer that needs to be passed to next `op_register_iter` call or
 ///         NULL if iteration is over.
 const void *op_register_iter(const void *const iter, char *const name,
-                             yankreg_T *const reg)
+                             yankreg_T *const reg, bool *is_unnamed)
   FUNC_ATTR_NONNULL_ARG(2, 3) FUNC_ATTR_WARN_UNUSED_RESULT
 {
   *name = NUL;
@@ -5796,6 +5796,7 @@ const void *op_register_iter(const void *const iter, char *const name,
   int iter_off = (int)(iter_reg - &(y_regs[0]));
   *name = (char)get_register_name(iter_off);
   *reg = *iter_reg;
+  *is_unnamed = (iter_reg == y_previous);
   while (++iter_reg - &(y_regs[0]) < NUM_SAVED_REGISTERS) {
     if (!reg_empty(iter_reg)) {
       return (void *) iter_reg;
@@ -5821,9 +5822,10 @@ size_t op_register_amount(void)
 ///
 /// @param[in]  name        Register name.
 /// @param[in]  reg         Register value.
+/// @param[in]  is_unnamed  Whether to set the unnamed regiseter to reg
 ///
 /// @return true on success, false on failure.
-bool op_register_set(const char name, const yankreg_T reg)
+bool op_register_set(const char name, const yankreg_T reg, bool is_unnamed)
 {
   int i = op_reg_index(name);
   if (i == -1) {
@@ -5831,6 +5833,10 @@ bool op_register_set(const char name, const yankreg_T reg)
   }
   free_register(&y_regs[i]);
   y_regs[i] = reg;
+
+  if (is_unnamed) {
+    y_previous = &y_regs[i];
+  }
   return true;
 }
 

src/nvim/shada.c

@@ -98,6 +98,7 @@ KHASH_SET_INIT_STR(strset)
 #define REG_KEY_TYPE "rt"
 #define REG_KEY_WIDTH "rw"
 #define REG_KEY_CONTENTS "rc"
+#define REG_KEY_UNNAMED "ru"
 
 #define KEY_LNUM "l"
 #define KEY_COL "c"
@@ -286,6 +287,7 @@ typedef struct {
       char **contents;
       size_t contents_size;
       size_t width;
+      bool is_unnamed;
       dict_T *additional_data;
     } reg;
     struct global_var {
@@ -1335,7 +1337,7 @@ static void shada_read(ShaDaReadDef *const sd_reader, const int flags)
           .y_width = (colnr_T) cur_entry.data.reg.width,
           .timestamp = cur_entry.timestamp,
           .additional_data = cur_entry.data.reg.additional_data,
-        })) {
+        }, cur_entry.data.reg.is_unnamed)) {
           shada_free_shada_entry(&cur_entry);
         }
         // Do not free shada entry: its allocated memory was saved above.
@@ -1780,6 +1782,7 @@ static ShaDaWriteResult shada_pack_entry(msgpack_packer *const packer,
           2  // Register contents and name
           + ONE_IF_NOT_DEFAULT(entry, reg.type)
           + ONE_IF_NOT_DEFAULT(entry, reg.width)
+          + ONE_IF_NOT_DEFAULT(entry, reg.is_unnamed)
           // Additional entries, if any:
           + (size_t) (entry.data.reg.additional_data == NULL
                       ? 0
@@ -1800,6 +1803,14 @@ static ShaDaWriteResult shada_pack_entry(msgpack_packer *const packer,
         PACK_STATIC_STR(REG_KEY_WIDTH);
         msgpack_pack_uint64(spacker, (uint64_t) entry.data.reg.width);
       }
+      if (!CHECK_DEFAULT(entry, reg.is_unnamed)) {
+        PACK_STATIC_STR(REG_KEY_UNNAMED);
+        if (entry.data.reg.is_unnamed) {
+          msgpack_pack_true(spacker);
+        } else {
+          msgpack_pack_false(spacker);
+        }
+      }
       DUMP_ADDITIONAL_DATA(entry.data.reg.additional_data, "register item");
       break;
     }
@@ -2591,7 +2602,8 @@ static ShaDaWriteResult shada_write(ShaDaWriteDef *const sd_writer,
     do {
       yankreg_T reg;
       char name = NUL;
-      reg_iter = op_register_iter(reg_iter, &name, &reg);
+      bool is_unnamed = false;
+      reg_iter = op_register_iter(reg_iter, &name, &reg, &is_unnamed);
       if (name == NUL) {
         break;
       }
@@ -2611,6 +2623,7 @@ static ShaDaWriteResult shada_write(ShaDaWriteDef *const sd_writer,
               .width = (size_t) (reg.y_type == kMTBlockWise ? reg.y_width : 0),
               .additional_data = reg.additional_data,
               .name = name,
+              .is_unnamed = is_unnamed,
             }
           }
         }
@@ -3594,6 +3607,7 @@ shada_read_next_item_start:
             entry->data.reg.contents[i] = BIN_CONVERTED(arr.ptr[i].via.bin);
           }
         }
+        BOOLEAN_KEY("register", REG_KEY_UNNAMED, entry->data.reg.is_unnamed)
         TYPED_KEY("register", REG_KEY_TYPE, "an unsigned integer",
                   entry->data.reg.type, POSITIVE_INTEGER, u64, TOU8)
         TYPED_KEY("register", KEY_NAME_CHAR, "an unsigned integer",