feat(decode_string): decode binary string with NULs to Blob

Strings that previously decoded into a msgpack special for representing
BINs with NULs now convert to Blobs. It shouldn't be possible to decode
into this special anymore after this change?

Notably, Lua strings with NULs now convert to Blobs when passed to VimL.

1 files changed, 25 insertions, 17 deletions

diff --git a/src/nvim/eval/decode.c b/src/nvim/eval/decode.c
index 89e1f04bfd..5c03f55621 100644
--- a/src/nvim/eval/decode.c
+++ b/src/nvim/eval/decode.c
@@ -246,14 +246,15 @@ list_T *decode_create_map_special_dict(typval_T *const ret_tv,
 /// Convert char* string to typval_T
 ///
 /// Depending on whether string has (no) NUL bytes, it may use a special
-/// dictionary or decode string to VAR_STRING.
+/// dictionary, VAR_BLOB, or decode string to VAR_STRING.
 ///
 /// @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  If true, save special string type as kMPBinary,
-///                     otherwise kMPString.
+/// @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]  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.
@@ -269,21 +270,28 @@ typval_T decode_string(const char *const s, const size_t len,
                               ? ((s != NULL) && (memchr(s, NUL, len) != NULL))
                               : (bool)hasnul);
   if (really_hasnul) {
-    list_T *const list = tv_list_alloc(kListLenMayKnow);
-    tv_list_ref(list);
     typval_T tv;
-    create_special_dict(&tv, binary ? kMPBinary : 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 };
+    tv.v_lock = VAR_UNLOCKED;
+    if (binary) {
+      tv_blob_alloc_ret(&tv);
+      ga_concat_len(&tv.vval.v_blob->bv_ga, s, 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 };
+      }
     }
     return tv;
   } else {