From: Sjors Provoost <sjors@sprovoost.nl>
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Date: Thu, 7 Mar 2019 14:59:47 +0100
References: <CAK51vgDO2Tg38XbW0pqAnO3ETJ_qf8owRsUYsTXmrf7H2yGZtw@mail.gmail.com>
	<q5otmg$4vh7$1@blaine.gmane.org>
To: Andreas Schildbach <andreas@schildbach.de>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
In-Reply-To: <q5otmg$4vh7$1@blaine.gmane.org>
Message-Id: <78CAF294-56E2-477C-B46F-C65A56357820@sprovoost.nl>
Subject: Re: [bitcoin-dev] Removal of reject network messages from Bitcoin
 Core (BIP61)
Precedence: list

Can you elaborate a bit on what kind of reject messages your users are =
getting? I assume the users wallet connects directly to the Bitcoin p2p =
network?

What does the wallet do when a transaction is rejected? Does it forget =
about it (that seems unsafe) or compose another one (with overlapping =
inputs)?

Sjors

> Op 6 mrt. 2019, om 17:49 heeft Andreas Schildbach via bitcoin-dev =
<bitcoin-dev@lists.linuxfoundation.org> het volgende geschreven:
>=20
> Reject messages cannot be replaced for debugging user problems. At =
least
> unless you plan to make RPC or bitcoind logfiles available via the P2P
> protocol (both probably not a good idea).
>=20
> The typical case is, I get mailed a wallet logfile with reject =
messages
> and that's all I have. I cannot access the bitcoind logfile(s) of the
> node(s) that generated the reject message in the first place. Nor can =
I
> access their RPC interface.
>=20
> I strongly suggest re-enabling reject messages by default before 0.18.
>=20
>=20
> On 06/03/2019 01.53, Marco Falke via bitcoin-dev wrote:
>> Bitcoin Core may send "reject" messages as response to "tx", "block" =
or
>> "version" messages from a network peer when the message could not be =
accepted.
>>=20
>> This feature is toggled by the `-enablebip61` command line option and =
has been
>> disabled by default since Bitcoin Core version 0.18.0 (not yet =
released as of
>> time of writing). Nodes on the network can not generally be trusted =
to send
>> valid ("reject") messages, so this should only ever be used when =
connected to a
>> trusted node. At this time, I am not aware of any software that =
requires this
>> feature, and I would like to remove if from Bitcoin Core to make the =
codebase
>> slimmer, easier to understand and maintain. Let us know if your =
application
>> relies on this feature and you can not use any of the recommended =
alternatives:
>>=20
>> * Testing or debugging of implementations of the Bitcoin P2P network =
protocol
>>  should be done by inspecting the log messages that are produced by a =
recent
>>  version of Bitcoin Core. Bitcoin Core logs debug messages
>>  (`-debug=3D<category>`) to a stream (`-printtoconsole`) or to a file
>>  (`-debuglogfile=3D<debug.log>`).
>>=20
>> * Testing the validity of a block can be achieved by specific RPCs:
>>  - `submitblock`
>>  - `getblocktemplate` with `'mode'` set to `'proposal'` for blocks =
with
>>    potentially invalid POW
>>=20
>> * Testing the validity of a transaction can be achieved by specific =
RPCs:
>>  - `sendrawtransaction`
>>  - `testmempoolaccept`
>>=20
>> * Wallets should not use the absence of "reject" messages to indicate =
a
>>  transaction has propagated the network, nor should wallets use =
"reject"
>>  messages to set transaction fees. Wallets should rather use fee =
estimation
>>  to determine transaction fees and set replace-by-fee if desired. =
Thus, they
>>  could wait until the transaction has confirmed (taking into account =
the fee
>>  target they set (compare the RPC `estimatesmartfee`)) or listen for =
the
>>  transaction announcement by other network peers to check for =
propagation.
>>=20
>> I propose to remove "reject" messages from Bitcoin Core 0.19.0 unless =
there are
>> valid concerns about its removal.
>>=20
>> Marco
>>=20
>=20
>=20
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