Delivery-date: Sun, 16 Feb 2025 03:59:04 -0800
Sender: bitcoindev@googlegroups.com
Date: Sat, 15 Feb 2025 13:13:24 -0800 (PST)
From: Antoine Riard <antoine.riard@gmail.com>
To: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Message-Id: <97c36a7a-fe4d-4e24-8bbb-a55b7284fe71n@googlegroups.com>
In-Reply-To: <Z6-AD12xTqxCxjqf@petertodd.org>
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Subject: Re: [bitcoindev] Update on the Great Consensus Cleanup Revival
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Hi Peter,

I'm talking about this check in VerifyScript as of commit 43e71f74 in=20
bitcoin core.

```
    if ((flags & SCRIPT_VERIFY_SIGPUSHONLY) !=3D 0 &&=20
!scriptSig.IsPushOnly()) {
        return set_error(serror, SCRIPT_ERR_SIG_PUSHONLY);
    }
```

In my understanding, we never set SCRIPT_VERIFY_SIGPUSHONLY, neither in=20
MANDATORY_SCRIPT_VERIFY_FLAGS,
nor in STANDARD_SCRIPT_VERIFY_FLAGS, and this sounds okay as it's a script=
=20
check pertaining to BIP62
rule 2, and BIP62 was never activated. As far as I can tell, that's more a=
=20
stale check just right=20
there in the interpreter code paths.

We still return SCRIPT_ERR_SIG_PUSHONLY for P2SH spends, verifying the=20
scriptSig is push-only.

All the unit tests (i.e `script_tests.cpp`) are manually setting the=20
SCRIPT_VERIFY_SIGPUSHONLY flag
to verify the logic correctness, even it appears as never being set for=20
block validation.

The original PR is there: https://github.com/bitcoin/bitcoin/pull/5065

Feel free to point me out if I'm missing something obvious here.

Best,
Antoine
OTS hash: 42e2e614fea49ec876539e28b323718df3ef734b3a4b247fcc649f0704ea1b61
Le vendredi 14 f=C3=A9vrier 2025 =C3=A0 17:45:54 UTC, Peter Todd a =C3=A9cr=
it :

> On Fri, Feb 07, 2025 at 05:02:46AM -0800, Antoine Riard wrote:
> > This might be a stylistic note, though I could point in bitcoin core=20
> code=20
> > today implemented
> > check in the script interpreter right in the crux of consensus code=20
> paths=20
> > that is just stale
> > due to a never-activated BIP (-- yes I'm starring at you SIGPUSHONLY).
>
> What specifically do you mean by this? You mean the
> SCRIPT_ERR_SIG_PUSHONLY error condition?
>
> --=20
> https://petertodd.org 'peter'[:-1]@petertodd.org
>

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Hi Peter,<br /><br />I'm talking about this check in VerifyScript as of com=
mit 43e71f74 in bitcoin core.<br /><br />```<br />=C2=A0 =C2=A0 if ((flags =
&amp; SCRIPT_VERIFY_SIGPUSHONLY) !=3D 0 &amp;&amp; !scriptSig.IsPushOnly())=
 {<br />=C2=A0 =C2=A0 =C2=A0 =C2=A0 return set_error(serror, SCRIPT_ERR_SIG=
_PUSHONLY);<br />=C2=A0 =C2=A0 }<br />```<br /><br />In my understanding, w=
e never set SCRIPT_VERIFY_SIGPUSHONLY, neither in MANDATORY_SCRIPT_VERIFY_F=
LAGS,<br />nor in STANDARD_SCRIPT_VERIFY_FLAGS, and this sounds okay as it'=
s a script check pertaining to BIP62<br />rule 2, and BIP62 was never activ=
ated. As far as I can tell, that's more a stale check just right <br />ther=
e in the interpreter code paths.<br /><br />We still return SCRIPT_ERR_SIG_=
PUSHONLY for P2SH spends, verifying the scriptSig is push-only.<br /><br />=
All the unit tests (i.e `script_tests.cpp`) are manually setting the SCRIPT=
_VERIFY_SIGPUSHONLY flag<br />to verify the logic correctness, even it appe=
ars as never being set for block validation.<br /><br />The original PR is =
there: https://github.com/bitcoin/bitcoin/pull/5065<br /><br />Feel free to=
 point me out if I'm missing something obvious here.<br /><br />Best,<br />=
Antoine<br />OTS hash: 42e2e614fea49ec876539e28b323718df3ef734b3a4b247fcc64=
9f0704ea1b61<br /><div class=3D"gmail_quote"><div dir=3D"auto" class=3D"gma=
il_attr">Le vendredi 14 f=C3=A9vrier 2025 =C3=A0 17:45:54 UTC, Peter Todd a=
 =C3=A9crit=C2=A0:<br/></div><blockquote class=3D"gmail_quote" style=3D"mar=
gin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: =
1ex;">On Fri, Feb 07, 2025 at 05:02:46AM -0800, Antoine Riard wrote:
<br>&gt; This might be a stylistic note, though I could point in bitcoin co=
re code=20
<br>&gt; today implemented
<br>&gt; check in the script interpreter right in the crux of consensus cod=
e paths=20
<br>&gt; that is just stale
<br>&gt; due to a never-activated BIP (-- yes I&#39;m starring at you SIGPU=
SHONLY).
<br>
<br>What specifically do you mean by this? You mean the
<br>SCRIPT_ERR_SIG_PUSHONLY error condition?
<br>
<br>--=20
<br><a href=3D"https://petertodd.org" target=3D"_blank" rel=3D"nofollow" da=
ta-saferedirecturl=3D"https://www.google.com/url?hl=3Dfr&amp;q=3Dhttps://pe=
tertodd.org&amp;source=3Dgmail&amp;ust=3D1739740336967000&amp;usg=3DAOvVaw2=
R5OF6_OMmQmcP5By1hwUJ">https://petertodd.org</a> &#39;peter&#39;[:-1]@<a hr=
ef=3D"http://petertodd.org" target=3D"_blank" rel=3D"nofollow" data-safered=
irecturl=3D"https://www.google.com/url?hl=3Dfr&amp;q=3Dhttp://petertodd.org=
&amp;source=3Dgmail&amp;ust=3D1739740336967000&amp;usg=3DAOvVaw3gQoNAsh87fH=
YcS42yF758">petertodd.org</a>
<br></blockquote></div>

<p></p>

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