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Posted to users@subversion.apache.org by "Dr. Rolf Jansen" <rj...@obsigna.com> on 2018/11/05 22:21:20 UTC
subversion 1.11.0 on FreeBSD 11.2: ... does not support the HTTP/DAV
protocol
The default version of Subversion in the Ports of FreeBSD has been switched from 1.10.3 to 1.11.0 in the last week. After running the monthly update of my FreeBSD machines I cannot connect to HTTPS repositories anymore.
I submitted a bug report to FreeBSD, see: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=232945
The FreeBSD subversion port maintainer, verified that the same issue happens with subversion 1.11 on Linux and Windows as well, and he asked me to report the issue here.
In the meantime I deinstalled all subversion packages built from the FreeBSD ports system, and I built and installed subversion 1.11.0 from the upstream sources (thats’s yours) - see below. Needless to say that 1.10.3 does not show the issue below, and of course the GitHub server does support HTTP/DAV.
# fetch http://mirror.nbtelecom.com.br/apache/subversion/subversion-1.11.0.tar.bz2
# tar -oxjf subversion-1.11.0.tar.bz2
# cd subversion-1.11.0
# ./configure
# make install clean
# svn --version
svn, version 1.11.0 (r1845130)
compiled Nov 5 2018, 20:12:13 on x86_64-unknown-freebsd11.2
Copyright (C) 2018 The Apache Software Foundation.
This software consists of contributions made by many people;
see the NOTICE file for more information.
Subversion is open source software, see http://subversion.apache.org/
The following repository access (RA) modules are available:
* ra_svn : Module for accessing a repository using the svn network protocol.
- handles 'svn' scheme
* ra_local : Module for accessing a repository on local disk.
- handles 'file' scheme
* ra_serf : Module for accessing a repository via WebDAV protocol using serf.
- using serf 1.3.9 (compiled with 1.3.9)
- handles 'http' scheme
- handles 'https' scheme
The following authentication credential caches are available:
* Plaintext cache in /root/.subversion
* GPG-Agent
# svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by Kris Deugau <kd...@vianet.ca>.
Dr. Rolf Jansen wrote:
> The default version of Subversion in the Ports of FreeBSD has been switched from 1.10.3 to 1.11.0 in the last week. After running the monthly update of my FreeBSD machines I cannot connect to HTTPS repositories anymore.
>
> I submitted a bug report to FreeBSD, see: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=232945
>
> The FreeBSD subversion port maintainer, verified that the same issue happens with subversion 1.11 on Linux and Windows as well, and he asked me to report the issue here.
>
> In the meantime I deinstalled all subversion packages built from the FreeBSD ports system, and I built and installed subversion 1.11.0 from the upstream sources (thats’s yours) - see below. Needless to say that 1.10.3 does not show the issue below, and of course the GitHub server does support HTTP/DAV.
If you check the list archives, you'll see that the thread immediately
before yours, "Problems accessing GitHub's SVN-bridge with SVN 1.11", is
about the exact same issue.
Unless I've completely misunderstood that thread, GitHub's custom
re-implmentation of SVN's HTTP/DAV support is slightly buggy, in that it
does not actually properly implement the underlying HTTP DAV protocol.
It's only now become an issue due to Subversion getting stricter about
checking for DAV protocol elements to better report certain errors.
-kgd
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by Branko Čibej <br...@apache.org>.
On 06.11.2018 00:28, Dr. Rolf Jansen wrote:
>> Am 05.11.2018 um 20:43 schrieb Stefan Sperling <st...@elego.de>:
>>
>> On Mon, Nov 05, 2018 at 08:21:20PM -0200, Dr. Rolf Jansen wrote:
>>> and of course the GitHub server does support HTTP/DAV.
No it does not. It does not implement the most basic requirements of
that protocol, which would be to return a response header saying "DAV:
1". See https://www.ietf.org/rfc/rfc2518.txt section 15.1.
>>> # svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
>>> svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
>>> svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
>> There is a problem at Github's end with SVN 1.11.
>>
>> See the thread titled "Problems accessing GitHub's SVN-bridge with SVN 1.11"
>> on this very mailing list: https://svn.haxx.se/users/archive-2018-11/0008.shtml
> In the meantime, I saw this thread.
>
>> There is a problem at Github’s end with SVN 1.11.
>
> Reading the whole thread, my impression is that there is another issue with the Robustness Principle of software design on Subversion’s end. See: https://en.wikipedia.org/wiki/Robustness_principle.
We're extremely liberal with that we accept, but it has to at least
marginally follow the protocol specification.
> I won’t hold on my breath, until the Subversion Developers and the GitHub engineers sorted out their animosities. I put the patch shown below to /usr/ports/devel/subversion/files/patch-zz-DAV-robustness.local on my FreeBSD system, and then I reinstalled the port - problem solved. Happy discussions!
Good for you. If you ever get an error saying "Malformed XML in
response," please don't ask us to fix it.
-- Brane
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by "Dr. Rolf Jansen" <rj...@obsigna.com>.
> Am 05.11.2018 um 21:55 schrieb Nico Kadel-Garcia <nk...@gmail.com>:
>
> On Mon, Nov 5, 2018 at 6:28 PM Dr. Rolf Jansen <rj...@obsigna.com> wrote:
>>
>>> Am 05.11.2018 um 20:43 schrieb Stefan Sperling <st...@elego.de>:
>>>
>>> On Mon, Nov 05, 2018 at 08:21:20PM -0200, Dr. Rolf Jansen wrote:
>>>> and of course the GitHub server does support HTTP/DAV.
>>>
>>>> # svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
>>>> svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
>>>> svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
>>>
>>> There is a problem at Github's end with SVN 1.11.
>>>
>>> See the thread titled "Problems accessing GitHub's SVN-bridge with SVN 1.11"
>>> on this very mailing list: https://svn.haxx.se/users/archive-2018-11/0008.shtml
>>
>> In the meantime, I saw this thread.
>>
>>> There is a problem at Github’s end with SVN 1.11.
>>
>>
>> Reading the whole thread, my impression is that there is another issue with the Robustness Principle of software design on Subversion’s end. See: https://en.wikipedia.org/wiki/Robustness_principle.
>>
>> I won’t hold on my breath, until the Subversion Developers and the GitHub engineers sorted out their animosities. I put the patch shown below to /usr/ports/devel/subversion/files/patch-zz-DAV-robustness.local on my FreeBSD system, and then I reinstalled the port - problem solved. Happy discussions!
>>
>> Best regards
>>
>> Rolf
>
> May I suggest never simply expanding a comment to take out a chunk of
> live code ,such as you've done in your patch? If you have to take out
> a chunk of live code, add a *separate* coment about why you're doing
> it, and add a distinct set of comment marks around it. This will make
> merges *much* cleaner for the future.
>
>> --- subversion/libsvn_ra_serf/options.c.orig 2018-02-25 10:22:55.000000000 -0300
>> +++ subversion/libsvn_ra_serf/options.c 2018-11-05 20:50:29.431635000 -0200
>> @@ -403,7 +403,7 @@ options_response_handler(serf_request_t
>>
>> /* Bail out early if we're not talking to a DAV server.
>> Note that this check is only valid if we've received a success
>> - response; redirects and errors don't count. */
>> + response; redirects and errors don't count.
>> if (opt_ctx->handler->sline.code >= 200
>> && opt_ctx->handler->sline.code < 300
>> && !opt_ctx->received_dav_header)
>> @@ -413,7 +413,7 @@ options_response_handler(serf_request_t
>> _("The server at '%s' does not support the HTTP/DAV protocol"),
>> session->session_url_str);
>> }
>> -
>> + */
>> /* Assume mergeinfo capability unsupported, if didn't receive information
>> about server or repository mergeinfo capability. */
>> if (!svn_hash_gets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO))
In general, you’re right, in the special case, the patch is meant to be used as a hot fix on FreeBSD production systems, and it is in no way meant to make it into the upstream code base.
Best regards
Rolf
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by Nico Kadel-Garcia <nk...@gmail.com>.
On Mon, Nov 5, 2018 at 6:28 PM Dr. Rolf Jansen <rj...@obsigna.com> wrote:
>
> > Am 05.11.2018 um 20:43 schrieb Stefan Sperling <st...@elego.de>:
> >
> > On Mon, Nov 05, 2018 at 08:21:20PM -0200, Dr. Rolf Jansen wrote:
> >> and of course the GitHub server does support HTTP/DAV.
> >
> >> # svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
> >> svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
> >> svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
> >
> > There is a problem at Github's end with SVN 1.11.
> >
> > See the thread titled "Problems accessing GitHub's SVN-bridge with SVN 1.11"
> > on this very mailing list: https://svn.haxx.se/users/archive-2018-11/0008.shtml
>
> In the meantime, I saw this thread.
>
> > There is a problem at Github’s end with SVN 1.11.
>
>
> Reading the whole thread, my impression is that there is another issue with the Robustness Principle of software design on Subversion’s end. See: https://en.wikipedia.org/wiki/Robustness_principle.
>
> I won’t hold on my breath, until the Subversion Developers and the GitHub engineers sorted out their animosities. I put the patch shown below to /usr/ports/devel/subversion/files/patch-zz-DAV-robustness.local on my FreeBSD system, and then I reinstalled the port - problem solved. Happy discussions!
>
> Best regards
>
> Rolf
May I suggest never simply expanding a comment to take out a chunk of
live code ,such as you've done in your patch? If you have to take out
a chunk of live code, add a *separate* coment about why you're doing
it, and add a distinct set of comment marks around it. This will make
merges *much* cleaner for the future.
> --- subversion/libsvn_ra_serf/options.c.orig 2018-02-25 10:22:55.000000000 -0300
> +++ subversion/libsvn_ra_serf/options.c 2018-11-05 20:50:29.431635000 -0200
> @@ -403,7 +403,7 @@ options_response_handler(serf_request_t
>
> /* Bail out early if we're not talking to a DAV server.
> Note that this check is only valid if we've received a success
> - response; redirects and errors don't count. */
> + response; redirects and errors don't count.
> if (opt_ctx->handler->sline.code >= 200
> && opt_ctx->handler->sline.code < 300
> && !opt_ctx->received_dav_header)
> @@ -413,7 +413,7 @@ options_response_handler(serf_request_t
> _("The server at '%s' does not support the HTTP/DAV protocol"),
> session->session_url_str);
> }
> -
> + */
> /* Assume mergeinfo capability unsupported, if didn't receive information
> about server or repository mergeinfo capability. */
> if (!svn_hash_gets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO))
>
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by Stefan Sperling <st...@elego.de>.
On Tue, Nov 06, 2018 at 11:09:53AM +0100, Branko Čibej wrote:
> On 06.11.2018 10:20, Dr. Rolf Jansen wrote:
> > Said all this, I would have simply amended this error message by a hint. „... check the URL is pointing to a SVN repository!“.
>
> ... and this hint implies that only the URL could be wrong, so it's
> misleading.
I agree with Rolf that users will appreciate a hint about the URL
potentially being wrong. If it is phrased in a way that does not suggest
the URL as the only possible root cause for the user's problem, then I
don't see a downside.
This is similar to the message we print when the working copy has a newer
revision than the repository. In that case we add a hint to the error
message that the repository might be hosted on a write-through proxy
that could be out of date, an assumption which might not be true at all.
I don't agree with Rolf about creating drama around this issue.
The likely outcome is that github will adapt their implementation soon.
Until that happens we can stay friends and go about our lives, rather
than accusing each other of violating sacred principles of software
engineering.
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by Branko Čibej <br...@apache.org>.
On 06.11.2018 10:20, Dr. Rolf Jansen wrote:
> For a DAV noob, this error message is IMHO indeed not very helpful. You need to know that DAV is heavily based on XML. However, I have my doubts, that the other message „does not support the HTTP/DAV protocol“ is much more helpful to a SVN noob, because you need to know that in the given respect SVN is utilizing the DAV protocol. So far to the term non-solution.
That's not quite the case. Certainly the error message could be
better/different, but point is to have one specific enough that it's
easy to find the cause; it took less than 5 minutes in the reported
case. Ease of maintenance and issue triage are important.
> Complex, because this was not achieved by simply rephrasing the misleading error message,
It's not easily rephrased because it's a valid error. The server could
be attempting to respond correctly to a DAV request but for some reason
messing up the XML in the response, or it could not be sending a DAV
response at all. In order to tell the difference, one must first know if
we're parsing a DAV response. There are two ways to do this: the simple
one is to look for the mandatory DAV: header; the complex and
error-prone one is to see if the response looks vaguely like the XML one
might expect.
> but by adding another obstacle into the connection protocol and throwing a new message if somebody stumbles across.
I'm a bit amused by this talk of obstacles ... we're talking about a
well-defined protocol here, and yet you complain to the volunteers on
this project for implementing it, rather than to the paid staff at
GitHub for not implementing it. Oh the irony.
> Now in regards to the term non-problem. Misspelling of URL’s may happen to everybody, not only to noobs, and yes, I saw this „Malformed XML in response,“ in the past, I corrected the URL, pronto.
Again, good for you. Many of our users did not assume that the URL is
wrong but that there's something wrong with either the client or the
server ...
> Said all this, I would have simply amended this error message by a hint. „... check the URL is pointing to a SVN repository!“.
... and this hint implies that only the URL could be wrong, so it's
misleading.
-- Brane
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by "Dr. Rolf Jansen" <rj...@obsigna.com>.
> Am 06.11.2018 um 01:57 schrieb Daniel Shahaf <d....@daniel.shahaf.name>:
>
> Dr. Rolf Jansen wrote on Tue, 06 Nov 2018 00:27 -0200:
>> FYI, RFC 2518 has been obsoleted since 11 years by RFC 4918, and the
>> relevant chapter moved to 10.1:
>> https://tools.ietf.org/html/rfc4918#section-10.1, and yes there is still
>> written "the DAV server MUST return the DAV header". However, the RFC
>> does not require the DAV client to bail out if the server fails to do
>> so, this was your choice.
>
> There are two schools of thought: one, "be strict in what you send and
> lenient in what you accept"; two, "be strict in what you send and strict
> in what you accept". This list is not a good place to have
> a discussion about which one is better in general.
Of course, this is the choice of the subversion team as well. However, if you want to be taken serious on the second option then it would be better not to refer to a RFC which is outdated for 11 years, even if particularly not much changed. Read „having an issue with the Robustness principle“ means that you generally don’t adhere with it, it does not imply that it would be good to adhere to - as said already, your choice. I wrote a closed source Web/DAV server in C and I do like the principle.
> Instead, let's focus on
> the specific problem at hand. If you have an idea for how we might continue
> operating with GitHub without regressing the failure mode that that error
> message was added to fix, we’re all ears.
I came in here only because the FreeBSD port maintainer of Subversion told me to report my problem here. I came in late, others saw the same problem already. What I learned from that other thread is that somebody complained about the „misleading“ error message „Malformed XML in response,“ when pointing SVN to a plain web server, one which does not serve a SVN repository.
For a DAV noob, this error message is IMHO indeed not very helpful. You need to know that DAV is heavily based on XML. However, I have my doubts, that the other message „does not support the HTTP/DAV protocol“ is much more helpful to a SVN noob, because you need to know that in the given respect SVN is utilizing the DAV protocol. So far to the term non-solution.
Complex, because this was not achieved by simply rephrasing the misleading error message, but by adding another obstacle into the connection protocol and throwing a new message if somebody stumbles across.
Now in regards to the term non-problem. Misspelling of URL’s may happen to everybody, not only to noobs, and yes, I saw this „Malformed XML in response,“ in the past, I corrected the URL, pronto.
Said all this, I would have simply amended this error message by a hint. „... check the URL is pointing to a SVN repository!“.
> The obvious idea is to wait a few days for GitHub to make the one-line
> change to their server code which will fix the issue.
Well, I am able to wait. I placed temporary patches into the subversion port directories of my FreeBSD systems, and when a new Subversion comes out these will be removed automatically.
Best regards
Rolf
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the HTTP/DAV
protocol
Posted by Daniel Shahaf <d....@daniel.shahaf.name>.
Dr. Rolf Jansen wrote on Tue, 06 Nov 2018 00:27 -0200:
> FYI, RFC 2518 has been obsoleted since 11 years by RFC 4918, and the
> relevant chapter moved to 10.1:
> https://tools.ietf.org/html/rfc4918#section-10.1, and yes there is still
> written "the DAV server MUST return the DAV header". However, the RFC
> does not require the DAV client to bail out if the server fails to do
> so, this was your choice.
There are two schools of thought: one, "be strict in what you send and
lenient in what you accept"; two, "be strict in what you send and strict
in what you accept". This list is not a good place to have
a discussion about which one is better in general. Instead, let's focus on
the specific problem at hand. If you have an idea for how we might continue
operating with GitHub without regressing the failure mode that that error
message was added to fix, we're all ears.
The obvious idea is to wait a few days for GitHub to make the one-line
change to their server code which will fix the issue.
Cheers,
Daniel
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by "Dr. Rolf Jansen" <rj...@obsigna.com>.
> Am 05.11.2018 um 21:57 schrieb Branko Čibej:
>
>>> Am 05.11.2018 um 20:43 schrieb Stefan Sperling:
>>>
>>> On Mon, Nov 05, 2018 at 08:21:20PM -0200, Dr. Rolf Jansen wrote:
>>>> and of course the GitHub server does support HTTP/DAV.
>
> No it does not. It does not implement the most basic requirements of
> that protocol, which would be to return a response header saying "DAV:
> 1". See https://www.ietf.org/rfc/rfc2518.txt section 15.1.
FYI, RFC 2518 has been obsoleted since 11 years by RFC 4918, and the relevant chapter moved to 10.1: https://tools.ietf.org/html/rfc4918#section-10.1, and yes there is still written "the DAV server MUST return the DAV header". However, the RFC does not require the DAV client to bail out if the server fails to do so, this was your choice.
>>>> # svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
>>>> svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
>>>> svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
>>>
>>> There is a problem at Github's end with SVN 1.11.
>>>
>>> See the thread titled "Problems accessing GitHub's SVN-bridge with SVN 1.11"
>>> on this very mailing list: https://svn.haxx.se/users/archive-2018-11/0008.shtml
>>
>> In the meantime, I saw this thread.
>>
>>> There is a problem at Github’s end with SVN 1.11.
>>
>>
>> Reading the whole thread, my impression is that there is another issue with the Robustness Principle of software design on Subversion’s end. See: https://en.wikipedia.org/wiki/Robustness_principle.
>
> We're extremely liberal with that we accept, but it has to at least
> marginally follow the protocol specification.
>
>> I won’t hold on my breath, until the Subversion Developers and the GitHub engineers sorted out their animosities. I put the patch shown below to /usr/ports/devel/subversion/files/patch-zz-DAV-robustness.local on my FreeBSD system, and then I reinstalled the port - problem solved. Happy discussions!
>
> Good for you. If you ever get an error saying "Malformed XML in
> response,“ please don't ask us to fix it.
You’ll never find me asking for complex non-solutions to simple non-problems.
Best regards
Rolf
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by "Dr. Rolf Jansen" <rj...@obsigna.com>.
> Am 05.11.2018 um 20:43 schrieb Stefan Sperling <st...@elego.de>:
>
> On Mon, Nov 05, 2018 at 08:21:20PM -0200, Dr. Rolf Jansen wrote:
>> and of course the GitHub server does support HTTP/DAV.
>
>> # svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
>> svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
>> svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
>
> There is a problem at Github's end with SVN 1.11.
>
> See the thread titled "Problems accessing GitHub's SVN-bridge with SVN 1.11"
> on this very mailing list: https://svn.haxx.se/users/archive-2018-11/0008.shtml
In the meantime, I saw this thread.
> There is a problem at Github’s end with SVN 1.11.
Reading the whole thread, my impression is that there is another issue with the Robustness Principle of software design on Subversion’s end. See: https://en.wikipedia.org/wiki/Robustness_principle.
I won’t hold on my breath, until the Subversion Developers and the GitHub engineers sorted out their animosities. I put the patch shown below to /usr/ports/devel/subversion/files/patch-zz-DAV-robustness.local on my FreeBSD system, and then I reinstalled the port - problem solved. Happy discussions!
Best regards
Rolf
--- subversion/libsvn_ra_serf/options.c.orig 2018-02-25 10:22:55.000000000 -0300
+++ subversion/libsvn_ra_serf/options.c 2018-11-05 20:50:29.431635000 -0200
@@ -403,7 +403,7 @@ options_response_handler(serf_request_t
/* Bail out early if we're not talking to a DAV server.
Note that this check is only valid if we've received a success
- response; redirects and errors don't count. */
+ response; redirects and errors don't count.
if (opt_ctx->handler->sline.code >= 200
&& opt_ctx->handler->sline.code < 300
&& !opt_ctx->received_dav_header)
@@ -413,7 +413,7 @@ options_response_handler(serf_request_t
_("The server at '%s' does not support the HTTP/DAV protocol"),
session->session_url_str);
}
-
+ */
/* Assume mergeinfo capability unsupported, if didn't receive information
about server or repository mergeinfo capability. */
if (!svn_hash_gets(session->capabilities, SVN_RA_CAPABILITY_MERGEINFO))
Re: subversion 1.11.0 on FreeBSD 11.2: ... does not support the
HTTP/DAV protocol
Posted by Stefan Sperling <st...@elego.de>.
On Mon, Nov 05, 2018 at 08:21:20PM -0200, Dr. Rolf Jansen wrote:
> and of course the GitHub server does support HTTP/DAV.
> # svn co https://github.com/cyclaero/ContentCGI.git/trunk ContentCGI
> svn: E170013: Unable to connect to a repository at URL 'https://github.com/cyclaero/ContentCGI.git/trunk'
> svn: E175003: The server at 'https://github.com/cyclaero/ContentCGI.git/trunk' does not support the HTTP/DAV protocol
There is a problem at Github's end with SVN 1.11.
See the thread titled "Problems accessing GitHub's SVN-bridge with SVN 1.11"
on this very mailing list: https://svn.haxx.se/users/archive-2018-11/0008.shtml