cookie: flush better

The cookie flushing (saving to a cookie jar) should only be done if a
transfer has been started. This is now done by checking the
cookies->running field, which is not reset in curl_easy_reset() so the
saving works correctly even after a call to that.

Follow-up to fd6eb8d6e7

Verified by test 1920

Reported-by: Alexander Batischev
Fixes #20090
Closes #20094

tests/data/Makefile.am

@@ -233,7 +233,7 @@ test1800 test1801 test1802 \
 \
 test1900 test1901 test1902 test1903 test1904 test1905 test1906 test1907 \
 test1908 test1909 test1910 test1911 test1912 test1913 test1914 test1915 \
-test1916 test1917 test1918 test1919 \
+test1916 test1917 test1918 test1919 test1920 \
 \
 test1933 test1934 test1935 test1936 test1937 test1938 test1939 test1940 \
 test1941 test1942 test1943 test1944 test1945 test1946 test1947 test1948 \

tests/data/test1920

@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="US-ASCII"?>
+<testcase>
+<info>
+<keywords>
+cookies
+</keywords>
+</info>
+
+<reply>
+<data crlf="headers" nocheck="yes">
+HTTP/1.1 200 OK
+Date: Tue, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Set-Cookie: cookiename=cookiecontent;
+
+-foo-
+</data>
+</reply>
+
+# Client-side
+<client>
+
+<name>
+load cookies, perform then reset before cleanup
+</name>
+<server>
+http
+</server>
+<features>
+cookies
+</features>
+<tool>
+lib%TESTNUMBER
+</tool>
+
+<command>
+http://%HOSTIP:%HTTPPORT/ %LOGDIR/cookie%TESTNUMBER
+</command>
+<file name="%LOGDIR/cookie%TESTNUMBER">
+# Netscape HTTP Cookie File
+# https://curl.se/docs/http-cookies.html
+# This file was generated by libcurl! Edit at your own risk.
+
+example.com	FALSE	/	FALSE	0	has_js	1
+</file>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<file name="%LOGDIR/cookie%TESTNUMBER" mode="text">
+# Netscape HTTP Cookie File
+# https://curl.se/docs/http-cookies.html
+# This file was generated by libcurl! Edit at your own risk.
+
+%HOSTIP	FALSE	/	FALSE	0	cookiename	cookiecontent
+example.com	FALSE	/	FALSE	0	has_js	1
+</file>
+</verify>
+</testcase>

tests/libtest/Makefile.inc

@@ -103,7 +103,7 @@ TESTS_C = \
   lib1662.c \
   lib1900.c lib1901.c lib1902.c lib1903.c lib1905.c lib1906.c lib1907.c \
   lib1908.c           lib1910.c lib1911.c lib1912.c lib1913.c \
-  lib1915.c lib1916.c           lib1918.c lib1919.c \
+  lib1915.c lib1916.c           lib1918.c lib1919.c lib1920.c \
   lib1933.c lib1934.c lib1935.c lib1936.c lib1937.c lib1938.c lib1939.c \
   lib1940.c                                         lib1945.c \
   lib1947.c lib1948.c \

tests/libtest/lib1920.c

@@ -0,0 +1,55 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+#include "first.h"
+
+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);
+
+    if(!result) {
+      /* 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;
+}