"Variable length string identifier" is not defined anywhere, and the suggestion to use "0x00" is also deeply unclear. I assumed it meant a nul-terminated string!
Be explicit: you mean it must be a compact siz1\e unsigned int length, followed by that many identifier bytes, followed by a compact size unsigned int subtype, followed by optional keydata.
Signed-off-by: Rusty Russell rusty@rustcorp.com.au
"Variable length string identifier" is not defined anywhere, and the suggestion
to use "0x00" is also deeply unclear. I assumed it meant a nul-terminated
string!
Be explicit: you mean it must be a compact siz1\e unsigned int length, followed
by that many identifier bytes, followed by a compact size unsigned int subtype,
followed by optional keydata.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
132 | @@ -133,8 +133,8 @@ The currently defined global types are as follows: 133 | *** <tt>{32-bit uint}</tt> 134 | 135 | * Type: Proprietary Use Type <tt>PSBT_GLOBAL_PROPRIETARY = 0xFC</tt> 136 | -** Key: Variable length identifier prefix, followed by a subtype, followed by the key data itself. 137 | -*** <tt>{0xFC}|<prefix>|{subtype}|{key data}</tt> 138 | +** Key: Compact size unsigned integer, followed by identifier prefix of that length, followed by a subtype, followed by the key data itself. 139 | +*** <tt>{0xFC}|{prefixlen}|<prefix>|{subtype}|{key data}</tt>
The note on notation found earlier in the BIP indicates that <...> means "prefixed by compact size unsigned integer". So this is technically incorrect.
Thanks, I missed that!
Is this boutique notation used in other BIPs? I haven't seen it before and it was completely non-intuitive to me!
Is this boutique notation used in other BIPs? I haven't seen it before and it was completely non-intuitive to me!
I think I made up the notation as a placeholder and just never changed it to something else.
132 | @@ -133,8 +133,8 @@ The currently defined global types are as follows: 133 | *** <tt>{32-bit uint}</tt> 134 | 135 | * Type: Proprietary Use Type <tt>PSBT_GLOBAL_PROPRIETARY = 0xFC</tt> 136 | -** Key: Variable length identifier prefix, followed by a subtype, followed by the key data itself. 137 | -*** <tt>{0xFC}|<prefix>|{subtype}|{key data}</tt> 138 | +** Key: Compact size unsigned integer, followed by identifier prefix of that length, followed by a subtype, followed by the key data itself.
Because everything variable length in Bitcoin is prefixed by a compact size unsigned int, "Variable length ..." is the correct way to describe this. Further clarification of this should be in a parenthetical rather than listed as its own separate entity.
This isn't even true in this BIP.
The key data is variable length. It is not prefixed by a compact size unsigned int!
The key data is variable length. It is not prefixed by a compact size unsigned int!
Uhh... no? It definitely is prefixed by the size, it's just usually 0x01.
Not quite: the entire key is prefixed by the size. The keydata length is implied.
You also use 0 as a terminator in various places in this BIP, eschewing explicit length there.
And bitcoin uses NUL as a terminator on command names in the wire protocol (within a fixed length field, because reasons?)
Given this lack of consistency, I think we're best off being horribly explicit?
Closing in favor of more ambitious approach....