Cookies not saved if handle was reset before cleanup

[Minoru]

I did this

My software depends on libcurl for HTTP transfers. It uses the easy interface, and re-uses the handles for multiple transfers. In order to avoid leaking options (e.g. headers), the handle is reset after each transfer.

Commit fd6eb8d broke my test suite because cookies were no longer sent. The problem is that they aren't written to the cookie jar. Apparently what happens is:

1. I create a curl handle
2. I set all the options I need for the current transfer
3. I do the transfer with curl_easy_perform()
4. I reset the options with curl_easy_reset(), then set the CURLOPT_COOKIEJAR again
5. I destruct the handle with curl_easy_cleanup()

The last step used to write cookies to the cookiejar, but after the fd6eb8d it doesn't anymore.

I worked around this on my end by doing the reset before setting the options, but I still view this as a regression in curl which could affect my users if they upgrade libcurl without upgrading my software.

I expected the following

A curl handle that was used for HTTP transfers should write cookies into the cookie jar, even if that handle was reset with curl_easy_reset() after the transfer.

curl/libcurl version

curl 8.17 and newer

operating system

I reproduced this problem on the following platforms:

FreeBSD 14.3 with "latest" repositories

Arch Linux in a Podman container

Ubuntu 24.04.3 in a Podman container with curl built from source

Podman is running on Debian stable, uname -a: Linux dcf477645e4a 6.12.57+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.57-1 (2025-11-05) x86_64 x86_64 x86_64 GNU/Linux

[Minoru]

I forgot to mention that after resetting the handle, I set CURLOPT_COOKIEJAR again so the curl_easy_cleanup() knows where to write the cookies. Sorry I confused you. Should've overcame my laziness and written a proper reproducer ._.

[bagder]

Thanks. I have created a reproducer now and I just realized this CURLOPT_COOKIEJAR detail as well.

[bagder]

static CURLcode test_lib1920(const char *URL)
{
  CURLcode result = CURLE_OK;
  CURL *curl = NULL;

  curl_global_init(CURL_GLOBAL_ALL);

  curl = curl_easy_init();
  if(curl) {
    easy_setopt(curl, CURLOPT_COOKIEFILE, libtest_arg2);
    easy_setopt(curl, CURLOPT_COOKIEJAR,  libtest_arg2);
    easy_setopt(curl, CURLOPT_URL,        URL);
    easy_setopt(curl, CURLOPT_VERBOSE,    1L);

    result = curl_easy_perform(curl);

    /* doing a reset here should not change the cookie jar content */
    curl_easy_reset(curl);
    /* set the cookie jar name so that curl knows where to store the
       cookies after reset */
    easy_setopt(curl, CURLOPT_COOKIEJAR,  libtest_arg2);
  }

test_cleanup:
  curl_easy_cleanup(curl);
  curl_global_cleanup();
  return result;
}

[Minoru]

Thank you for such a speedy fix!