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<p>It's been several more months, but now I need to ask what
distributions you are 'supporting' here, Maxim and nginx team.<br>
</p>
<p>PCRE2 is in Debian, Ubuntu, CentOS, Fedora, and others. That
covers a large portion of the major distributions at play.</p>
<p>This has once again popped on my radar in Ubuntu as we are trying
to move pcre3 out of Main, and rely on pcre2. NGINX is one of the
few packages that hasn't had any changes to it to make it
PCRE2-supportable.</p>
<p>I also agree that Exim should not be the basis of support.</p>
<p><br>
</p>
<p>Is it possible to revisit this decision, and determine whether it
is possible to support PCRE2 as it is now 2019 and many things
seem to be switching to pcre2? Otherwise, we have to either</p>
<p>(1) Strip out PCRE support entirely in NGINX in Ubuntu, which
would break most if not all regex functionality.</p>
<p>(2) No longer consider nginx supported officially and drop it to
community-only support (which means I will be once again doing all
the work in Ubuntu to patch it, though this isn't new for me).</p>
<p><br>
</p>
<p>I would like to ask that this be re-discussed and revisited since
PCRE2 is far from 'new' and many things're switching to it, as
well as it being present in multiple major distributions now.</p>
<p><br>
</p>
<p>Thomas</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 9/19/18 3:19 AM, Mark Mielke wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CALm7yL2Qy49zUy2W7vB91YUfB4tH0jq3xonRFhznqXZYNri1GQ@mail.gmail.com">
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<div class="gmail_quote">
<div dir="ltr">On Tue, Sep 18, 2018 at 11:55 AM Maxim Dounin
<<a href="mailto:mdounin@mdounin.ru"
moz-do-not-send="true">mdounin@mdounin.ru</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">On Tue, Sep 18, 2018 at
08:12:20AM -0400, Thomas Ward wrote:<br>
> Downstream in Ubuntu, it has been proposed to demote
pcre3 and <br>
> use pcre2 instead as it is newer.<br>
> <a href="https://trac.nginx.org/nginx/ticket/720"
rel="noreferrer" target="_blank" moz-do-not-send="true">https://trac.nginx.org/nginx/ticket/720</a>
shows it was marked 4 <br>
> years ago that NGINX does not support pcre2. Are
there any <br>
> plans to use pcre2 instead of pcre3?<br>
There are no immediate plans.<br>
When we last checked, there were no problems with PCRE,
but PCRE2 <br>
wasn't available in most distributions we support, making
the <br>
switch mostly meaningless.<br>
</blockquote>
<div><br>
</div>
<div>I think there have been changes since then. PCRE2 was
new in 2015, but isn't new in 2018.</div>
<div><br>
</div>
<div>RHEL 7 (and clones) include libpcre2. I think this is a
pretty wide set of machines right here. I believe Ubuntu
16.04 LTS has libpcre2 which is another wide set. Fedora
has had it for a while now. I think that unless you go to
older releases, all major distributions should have PCRE2
by now.</div>
<div><br>
</div>
<div>I build haproxy with PCRE2 support.</div>
<div><br>
</div>
<div>One that was interesting to me, is that Git recently
(April, 2018?) switched to building with PCRE2 by default
when "USE_LIBPCRE=Yes" was specified:</div>
<div><br>
</div>
<div><a
href="https://github.com/git/git/commit/cac5351363c5713248b8494e1e58e282c0a5bde7"
moz-do-not-send="true">https://github.com/git/git/commit/cac5351363c5713248b8494e1e58e282c0a5bde7</a><br>
</div>
<div><br>
</div>
<div>I'm not sure about meaningless from a functionality
perspective. All new features are going into PCRE2. PCRE
is a stable branched with only bug fixes and security
problems fixed. The newest features, including performance
improvements, are all in PCRE2. I believe the reason it is
"PCRE2-10" instead of "PCRE-10", is because of API
changes, and the opportunity to improve or fix previous
API decisions. This then becomes the basis for all future
development free of the PCRE API shackles.</div>
<div><br>
</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<br>
Also, it looks like PCRE2 is still not supported even by
Exim, <br>
which is the parent project of PCRE and PCRE2:<br>
<br>
<a href="https://bugs.exim.org/show_bug.cgi?id=1878"
rel="noreferrer" target="_blank" moz-do-not-send="true">https://bugs.exim.org/show_bug.cgi?id=1878</a></blockquote>
<div><br>
</div>
<div>I don't think Exim should be the measure:</div>
<div><br>
</div>
<div>"<span style="color:rgb(0,0,0);font-family:"Times
New Roman";font-size:medium">PCRE was originally
written for the </span><a href="https://www.exim.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Exim
MTA</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, but is now used by many
high-profile open source projects, including </span><a
href="https://httpd.apache.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Apache</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.php.net/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">PHP</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="https://www.kde.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">KDE</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.postfix.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Postfix</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, and </span><a
href="https://nmap.org/" style="font-family:"Times
New Roman";font-size:medium" moz-do-not-send="true">Nmap</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">. PCRE has also found its
way into some well known commercial products, like </span><a
href="https://www.apple.com/safari/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Apple
Safari</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">. Some other interesting
projects using PCRE include </span><a
href="http://www.call-with-current-continuation.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Chicken</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.ferite.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Ferite</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.canonware.com/onyx/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Onyx</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.hypermail-project.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Hypermail</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://leafnode.sourceforge.net/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Leafnode</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.askemos.org/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Askemos</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, </span><a
href="http://www.wenlin.com/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">Wenlin</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">, and </span><a
href="http://8th-dev.com/"
style="font-family:"Times New
Roman";font-size:medium" moz-do-not-send="true">8th</a><span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium">."</span></div>
<div><br>
</div>
<div>This list is also far from complete. PCRE and PCRE2 are
widely used, and PCRE2 is where all current improvement is
occurring. Anybody waiting for Exim, will probably be
among the very last to switch.</div>
<div><br>
</div>
<div><br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
As such, adding PCRE2 support to nginx looks premature.<br>
</blockquote>
</div>
<div dir="ltr"><br>
</div>
<div dir="ltr"><br>
</div>
<div>Before writing the above, I was debating with myself
about when the right time to add support for a new component
release is. For some projects and some components, it will
be more important than others. For example, OpenSSL 1.1.1
with TLSv1.3 support might be considered premature for some
projects to support, and yet Nginx supports this newly
released version long before OpenSSL 1.1.1 is readily
available in a majority of distributions that you support. I
think in this case, OpenSSL 1.1.1 is of strategic importance
to Nginx, and this ensured it was on the roadmap. (However,
it still seems to be missing an ability to configure the
cipher suite... :-) )</div>
<div><br>
</div>
<div>I don't know if PCRE2 belongs on this roadmap. I think
there have been significant improvements with the JIT
compilation that could prove useful for higher performance
evaluation of regular expressions with Nginx, but I
personally don't have this requirement, so if after
considering all of the above - you still felt it was
premature, I wouldn't raise any concern personally. I just
want to make sure this is an informed position. :-)</div>
<div><br>
</div>
-- <br>
<div dir="ltr" class="gmail_signature">Mark Mielke <<a
href="mailto:mark.mielke@gmail.com" target="_blank"
moz-do-not-send="true">mark.mielke@gmail.com</a>><br>
<br>
</div>
</div>
</div>
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