[PATCH] remote-curl: Include curl_errorstr on SSL setup failures

[PATCH] remote-curl: Include curl_errorstr on SSL setup failures

[Shawn Pearce]

For curl error 35 (CURLE_SSL_CONNECT_ERROR) users need the
additional text stored in CURLOPT_ERRORBUFFER to debug why
the connection did not start. This is curl_errorstr inside
of http.c, so include that in the message if it is non-empty.

Sometimes HTTP response codes aren't yet available, such as
when the SSL setup fails. Don't include HTTP 0 in the message.

Signed-off-by: Shawn Pearce <spearce@spearce.org>
---
 remote-curl.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/remote-curl.c b/remote-curl.c
index c704857..f611432 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -439,8 +439,20 @@ static int run_slot(struct active_request_slot *slot,
 	err = run_one_slot(slot, results);
 
 	if (err != HTTP_OK && err != HTTP_REAUTH) {
-		error("RPC failed; result=%d, HTTP code = %ld",
-		      results->curl_result, results->http_code);
+		struct strbuf msg = STRBUF_INIT;
+		if (results->http_code && results->http_code != 200)
+			strbuf_addf(&msg, "HTTP %ld", results->http_code);
+		if (results->curl_result != CURLE_OK) {
+			if (msg.len)
+				strbuf_addch(&msg, ' ');
+			strbuf_addf(&msg, "curl %d", results->curl_result);
+			if (curl_errorstr[0]) {
+				strbuf_addch(&msg, ' ');
+				strbuf_addstr(&msg, curl_errorstr);
+			}
+		}
+		error("RPC failed; %s", msg.buf);
+		strbuf_release(&msg);
 	}
 
 	return err;
-- 
2.7.0

Re: [PATCH] remote-curl: Include curl_errorstr on SSL setup failures

[Jeff King]

On Sat, Feb 13, 2016 at 05:39:34PM -0800, Shawn Pearce wrote:

> For curl error 35 (CURLE_SSL_CONNECT_ERROR) users need the
> additional text stored in CURLOPT_ERRORBUFFER to debug why
> the connection did not start. This is curl_errorstr inside
> of http.c, so include that in the message if it is non-empty.

I think this is an all-around improvement. GitHub sometimes get support
requests for result=18 on a git-push, which is curl's code for "I dunno,
the remote end hung up". Having a human-readable message may make things
less confusing.

Unfortunately I cannot seem to create the problem at will to confirm
that it kicks in in this case[1], but it seems like it should just based on
reading your patch.

-Peff

[1] I tried inserting "exit(0)" in various places of receive-pack, and
    it seems make the protocol deadlock. Yikes.

Re: [PATCH] remote-curl: Include curl_errorstr on SSL setup failures

[Shawn Pearce]

On Sun, Feb 14, 2016 at 8:50 AM, Jeff King <peff@peff.net> wrote:
> On Sat, Feb 13, 2016 at 05:39:34PM -0800, Shawn Pearce wrote:
>
>> For curl error 35 (CURLE_SSL_CONNECT_ERROR) users need the
>> additional text stored in CURLOPT_ERRORBUFFER to debug why
>> the connection did not start. This is curl_errorstr inside
>> of http.c, so include that in the message if it is non-empty.
>
> I think this is an all-around improvement. GitHub sometimes get support
> requests for result=18 on a git-push, which is curl's code for "I dunno,
> the remote end hung up". Having a human-readable message may make things
> less confusing.

I have been trying to recreate the error 35 scenario, but after almost
a day of continuous attempts with a suspected broken Git I thus far
have not been able to reproduce it. *sigh*

What made me pick this up was I got another recent report of a Debian
system having trouble connecting to $DAY_JOB's HTTPS server, which
reminded me of [2]. I was going to revive that patch, but instead
decided to expand on the error reporting.

[2] http://article.gmane.org/gmane.comp.version-control.git/206770

> Unfortunately I cannot seem to create the problem at will to confirm
> that it kicks in in this case[1], but it seems like it should just based on
> reading your patch.
>
> -Peff
>
> [1] I tried inserting "exit(0)" in various places of receive-pack, and
>     it seems make the protocol deadlock. Yikes.

This actually doesn't surprise me. *sigh*

With all the pipes and libcurl in there, we must somewhere be ignoring
the fact that the HTTP server closed the connection.