refactor(typval)!: remove distinction of binary and nonbinary strings

This is a breaking change which will make refactor of typval and shada
code a lot easier. In particular, code that would use or check for
v:msgpack_types.binary in the wild would be broken. This appears to be
rarely used in existing plugins.

Also some cases where v:msgpack_type.string would be used to represent a
binary string of "string" type, we use a BLOB instead, which is
vimscripts native type for binary blobs, and already was used for BIN
formats when necessary.

msgpackdump(msgpackparse(data)) no longer preserves the distinction
of BIN and STR strings. This is very common behavior for
language-specific msgpack bindings. Nvim uses msgpack as a tool to
serialize its data. Nvim is not a tool to bit-perfectly manipulate
arbitrary msgpack data out in the wild.

The changed tests should indicate how behavior changes in various edge
cases.

1 files changed, 16 insertions, 48 deletions

diff --git a/src/nvim/eval/decode.c b/src/nvim/eval/decode.c
index d7df7bb150..13cd3274dd 100644
--- a/src/nvim/eval/decode.c
+++ b/src/nvim/eval/decode.c
@@ -247,45 +247,29 @@ list_T *decode_create_map_special_dict(typval_T *const ret_tv, const ptrdiff_t l
 ///
 /// @param[in]  s  String to decode.
 /// @param[in]  len  String length.
-/// @param[in]  hasnul  Whether string has NUL byte, not or it was not yet
-///                     determined.
-/// @param[in]  binary  Determines decode type if string has NUL bytes.
-///                     If true convert string to VAR_BLOB, otherwise to the
-///                     kMPString special type.
+/// @param[in]  force_blob  whether string always should be decoded as a blob,
+///                         or only when embedded NUL bytes were present
 /// @param[in]  s_allocated  If true, then `s` was allocated and can be saved in
 ///                          a returned structure. If it is not saved there, it
 ///                          will be freed.
 ///
 /// @return Decoded string.
-typval_T decode_string(const char *const s, const size_t len, const TriState hasnul,
-                       const bool binary, const bool s_allocated)
+typval_T decode_string(const char *const s, const size_t len, bool force_blob,
+                       const bool s_allocated)
   FUNC_ATTR_WARN_UNUSED_RESULT
 {
   assert(s != NULL || len == 0);
-  const bool really_hasnul = (hasnul == kNone
-                              ? ((s != NULL) && (memchr(s, NUL, len) != NULL))
-                              : (bool)hasnul);
-  if (really_hasnul) {
+  const bool use_blob = force_blob || ((s != NULL) && (memchr(s, NUL, len) != NULL));
+  if (use_blob) {
     typval_T tv;
     tv.v_lock = VAR_UNLOCKED;
-    if (binary) {
-      tv_blob_alloc_ret(&tv);
-      ga_concat_len(&tv.vval.v_blob->bv_ga, s, len);
+    blob_T *b = tv_blob_alloc_ret(&tv);
+    if (s_allocated) {
+      b->bv_ga.ga_data = (void *)s;
+      b->bv_ga.ga_len = (int)len;
+      b->bv_ga.ga_maxlen = (int)len;
     } else {
-      list_T *const list = tv_list_alloc(kListLenMayKnow);
-      tv_list_ref(list);
-      create_special_dict(&tv, kMPString,
-                          (typval_T){ .v_type = VAR_LIST,
-                                      .v_lock = VAR_UNLOCKED,
-                                      .vval = { .v_list = list } });
-      const int elw_ret = encode_list_write((void *)list, s, len);
-      if (s_allocated) {
-        xfree((void *)s);
-      }
-      if (elw_ret == -1) {
-        tv_clear(&tv);
-        return (typval_T) { .v_type = VAR_UNKNOWN, .v_lock = VAR_UNLOCKED };
-      }
+      ga_concat_len(&b->bv_ga, s, len);
     }
     return tv;
   }
@@ -405,7 +389,6 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
   char *str = xmalloc(len + 1);
   int fst_in_pair = 0;
   char *str_end = str;
-  bool hasnul = false;
 #define PUT_FST_IN_PAIR(fst_in_pair, str_end) \
   do { \
     if ((fst_in_pair) != 0) { \
@@ -426,9 +409,6 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
         uvarnumber_T ch;
         vim_str2nr(ubuf, NULL, NULL,
                    STR2NR_HEX | STR2NR_FORCE, NULL, &ch, 4, true, NULL);
-        if (ch == 0) {
-          hasnul = true;
-        }
         if (SURROGATE_HI_START <= ch && ch <= SURROGATE_HI_END) {
           PUT_FST_IN_PAIR(fst_in_pair, str_end);
           fst_in_pair = (int)ch;
@@ -476,10 +456,7 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
   PUT_FST_IN_PAIR(fst_in_pair, str_end);
 #undef PUT_FST_IN_PAIR
   *str_end = NUL;
-  typval_T obj = decode_string(str, (size_t)(str_end - str), hasnul ? kTrue : kFalse, false, true);
-  if (obj.v_type == VAR_UNKNOWN) {
-    goto parse_json_string_fail;
-  }
+  typval_T obj = decode_string(str, (size_t)(str_end - str), false, true);
   POP(obj, obj.v_type != VAR_STRING);
   goto parse_json_string_ret;
 parse_json_string_fail:
@@ -982,18 +959,8 @@ int msgpack_to_vim(const msgpack_object mobj, typval_T *const rettv)
     };
     break;
   case MSGPACK_OBJECT_STR:
-    *rettv = decode_string(mobj.via.bin.ptr, mobj.via.bin.size, kTrue, false,
-                           false);
-    if (rettv->v_type == VAR_UNKNOWN) {
-      return FAIL;
-    }
-    break;
   case MSGPACK_OBJECT_BIN:
-    *rettv = decode_string(mobj.via.bin.ptr, mobj.via.bin.size, kNone, true,
-                           false);
-    if (rettv->v_type == VAR_UNKNOWN) {
-      return FAIL;
-    }
+    *rettv = decode_string(mobj.via.bin.ptr, mobj.via.bin.size, false, false);
     break;
   case MSGPACK_OBJECT_ARRAY: {
     list_T *const list = tv_list_alloc((ptrdiff_t)mobj.via.array.size);
@@ -1016,7 +983,8 @@ int msgpack_to_vim(const msgpack_object mobj, typval_T *const rettv)
   }
   case MSGPACK_OBJECT_MAP: {
     for (size_t i = 0; i < mobj.via.map.size; i++) {
-      if (mobj.via.map.ptr[i].key.type != MSGPACK_OBJECT_STR
+      if ((mobj.via.map.ptr[i].key.type != MSGPACK_OBJECT_STR
+           && mobj.via.map.ptr[i].key.type != MSGPACK_OBJECT_BIN)
           || mobj.via.map.ptr[i].key.via.str.size == 0
           || memchr(mobj.via.map.ptr[i].key.via.str.ptr, NUL,
                     mobj.via.map.ptr[i].key.via.str.size) != NULL) {