Save altsvc cache in curl_easy_reset

[candrews]

I did this

I expect this block to save the altsvc cache to "altsvc.txt" but it does not.
When the curl_easy_reset line (noted with a comment) is removed, "altsvc.txt" is saved as expected.

/********* Sample code generated by the curl command line tool **********
 * All curl_easy_setopt() options are documented at:
 * https://curl.haxx.se/libcurl/c/curl_easy_setopt.html
 ************************************************************************/
#include <curl/curl.h>

int main(int argc, char *argv[])
{ 
  CURLcode ret;
  CURL *hnd;

  hnd = curl_easy_init();
  curl_easy_setopt(hnd, CURLOPT_BUFFERSIZE, 102400L);
  curl_easy_setopt(hnd, CURLOPT_URL, "https://integralblue.com");
  curl_easy_setopt(hnd, CURLOPT_NOPROGRESS, 1L);
  curl_easy_setopt(hnd, CURLOPT_USERAGENT, "curl/7.68.0");
  curl_easy_setopt(hnd, CURLOPT_MAXREDIRS, 50L);
  curl_easy_setopt(hnd, CURLOPT_HTTP_VERSION, (long)CURL_HTTP_VERSION_2TLS);
  curl_easy_setopt(hnd, CURLOPT_TCP_KEEPALIVE, 1L);
  curl_easy_setopt(hnd, CURLOPT_ALTSVC, "altsvc.txt");

  /* Here is a list of options the curl code used that cannot get generated
     as source easily. You may select to either not use them or implement
     them yourself.

  CURLOPT_WRITEDATA set to a objectpointer
  CURLOPT_INTERLEAVEDATA set to a objectpointer
  CURLOPT_WRITEFUNCTION set to a functionpointer
  CURLOPT_READDATA set to a objectpointer
  CURLOPT_READFUNCTION set to a functionpointer
  CURLOPT_SEEKDATA set to a objectpointer
  CURLOPT_SEEKFUNCTION set to a functionpointer
  CURLOPT_ERRORBUFFER set to a objectpointer
  CURLOPT_STDERR set to a objectpointer
  CURLOPT_HEADERFUNCTION set to a functionpointer
  CURLOPT_HEADERDATA set to a objectpointer

  */

  ret = curl_easy_perform(hnd);

  curl_easy_reset(hnd); // line added
  curl_easy_cleanup(hnd);
  hnd = NULL;

  return (int)ret;
}
/**** End of sample code ****/

Currently, the alt svc cache is only saved in curl_close which is called by curl_easy_cleanup:
https://github.com/curl/curl/blob/curl-7_68_0/lib/url.c#L383
https://github.com/curl/curl/blob/curl-7_68_0/lib/easy.c#L738

It should also be saved when curl_easy_reset is called.

I believe that adding

#ifdef USE_ALTSVC
  Curl_altsvc_save(data->asi, data->set.str[STRING_ALTSVC]);
#endif

at https://github.com/curl/curl/blob/curl-7_68_0/lib/easy.c#L941 would address this issue.

I expected the following

curl_easy_reset should save the altsvc cache file.

curl/libcurl version

$ curl --version
curl 7.68.0 (x86_64-pc-linux-gnu) libcurl/7.68.0 OpenSSL/1.1.1d zlib/1.2.11 brotli/1.0.7 libidn2/2.3.0 libssh2/1.9.0_DEV nghttp2/1.40.0 quiche/0.2.0 librtmp/2.3
Release-Date: 2020-01-08
Protocols: dict file ftp ftps gopher http https imap imaps pop3 pop3s rtmp rtsp scp sftp smtp smtps telnet tftp 
Features: alt-svc AsynchDNS brotli HTTP2 HTTP3 HTTPS-proxy IDN IPv6 Largefile libz Metalink NTLM SSL TLS-SRP UnixSockets

operating system

$ uname -a
Linux irrational 5.4.0-rc6 #2 SMP Fri Nov 8 19:09:49 EST 2019 x86_64 Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz GenuineIntel GNU/Linux

[bagder]

I don't think it should save the file in the reset call, but the reset should not impact the alt-svc cache so it should then be saved correctly by curl_easy_cleanup(). I take it you're saying that's not what's happening?

[bagder]

Ah, the reason it doesn't save the alt-svc cache is because the reset cleared the file name so it doesn't know where to store them any longer...