Merge f92d9c0c5f into 4a3ed6fc16

- using {} with single entries makes little sense
- when using {} sets with two entry lists, there can only be 64 to reach
  maximum number of URLs

Verify the max check in test 761

docs/libcurl/curl_easy_setopt.md

@@ -332,6 +332,12 @@ Callback for wildcard matching. See CURLOPT_FNMATCH_FUNCTION(3)
 
 Follow HTTP redirects. See CURLOPT_FOLLOWLOCATION(3)
 
+## CURLOPT_FORBID_RETRY_ON_REUSE
+
+Prevent curl from transparently retry a transfer on a new connection when a
+previously reused connection was reset or otherwise no longer unavailable.
+See CURLOPT_FORBID_RETRY_ON_REUSE(3)
+
 ## CURLOPT_FORBID_REUSE
 
 Prevent subsequent connections from reusing this. See CURLOPT_FORBID_REUSE(3)

docs/libcurl/opts/CURLOPT_FORBID_RETRY_ON_REUSE.md

@@ -0,0 +1,106 @@
+---
+c: Copyright (C) 2025 Hewlett Packard Enterprise Development LP
+SPDX-License-Identifier: curl
+Title: CURLOPT_FORBID_RETRY_ON_REUSE
+Section: 3
+Source: libcurl
+See-also:
+  - CURLOPT_FRESH_CONNECT (3)
+  - CURLOPT_FORBID_REUSE (3)
+Protocol:
+  - All
+Added-in: 8.16.0
+---
+
+# NAME
+
+CURLOPT_FORBID_RETRY_ON_REUSE - prevent retry in case of reused connection is reset
+
+# SYNOPSIS
+
+~~~c
+#include <curl/curl.h>
+
+CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FORBID_RETRY_ON_REUSE,
+                          long forbid_retry);
+~~~
+
+# DESCRIPTION
+
+Pass a long. Set *forbid_retry* to 1 to prevent libcurl from resubmitting a
+transfer on a new connection when the previous reused connection was reset.
+Instead, the reset is returned to the caller as a `CURLE_RECV_ERROR`.
+
+This option only affects retry decision if the connection used to perform
+the request (and from which CURL received a TCP reset) is reused.
+
+Normally, libcurl considers connection resets on reused connections as a
+transient timing issue. The reset event is only visible to curl at the time
+libcurl attempts to issue transfer on that connection. As a result,
+sometimes libcurl may issue more than 1 identical transfers in a row on
+different connections with a single `curl_easy_perform()` call. Caller is
+not informed about any previous transfer attempts that may or may not have
+arrived at the server before the reset happened.
+
+This can break transactional application-level protocols if the protocol
+state machine considers connection state changes as part of state
+transition edges, or the protocol involves non-idempotent requests with
+side effects.
+
+Before introduction of this option, the only way to avoid unobservable
+retries was to set CURLOPT_FORBID_REUSE(3) to 1. However, without
+connection reuse and keepalive, the application pays significant
+overhead from the TCP and TLS handshake for every transfer. This option
+decouples implicit retry behavior from connection reuse, allowing the
+application to benefit from connection reuse without risking unobservable
+retries.
+
+Set to 0 to have libcurl transparently retry the transfer on a new
+connection if the reused connection was reset (default behavior).
+
+# DEFAULT
+
+0
+
+# %PROTOCOLS%
+
+# EXAMPLE
+
+~~~c
+#include <unistd.h>
+
+int main(void)
+{
+  CURL *curl = curl_easy_init();
+  if(curl) {
+    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
+    curl_easy_setopt(curl, CURLOPT_FORBID_RETRY_ON_REUSE, 1L);
+
+    /*
+     * This request will establish a connection and retained it for reuse
+     * after the transfer is done.
+     */
+    curl_easy_perform(curl);
+
+    /* Wait long enough for the server to drop connection. */
+    sleep(60);
+
+    /*
+     * curl will fail this request from the reset instead of
+     * transmitting the same transfer again over a new connection.
+     */
+    curl_easy_perform(curl);
+
+    curl_easy_cleanup(curl);
+  }
+}
+~~~
+
+# %AVAILABILITY%
+
+# RETURN VALUE
+
+curl_easy_setopt(3) returns a CURLcode indicating success or error.
+
+CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
+libcurl-errors(3).

docs/libcurl/opts/Makefile.inc

@@ -185,6 +185,7 @@ man_MANS =                                      \
   CURLOPT_FNMATCH_DATA.3                        \
   CURLOPT_FNMATCH_FUNCTION.3                    \
   CURLOPT_FOLLOWLOCATION.3                      \
+  CURLOPT_FORBID_RETRY_ON_REUSE.3               \
   CURLOPT_FORBID_REUSE.3                        \
   CURLOPT_FRESH_CONNECT.3                       \
   CURLOPT_FTP_ACCOUNT.3                         \

docs/libcurl/symbols-in-versions

@@ -646,6 +646,7 @@ CURLOPT_FILETIME                7.5
 CURLOPT_FNMATCH_DATA            7.21.0
 CURLOPT_FNMATCH_FUNCTION        7.21.0
 CURLOPT_FOLLOWLOCATION          7.1
+CURLOPT_FORBID_RETRY_ON_REUSE   8.16.0
 CURLOPT_FORBID_REUSE            7.7
 CURLOPT_FRESH_CONNECT           7.7
 CURLOPT_FTP_ACCOUNT             7.13.0

include/curl/curl.h

@@ -2258,6 +2258,10 @@ typedef enum {
   /* set TLS supported signature algorithms */
   CURLOPT(CURLOPT_SSL_SIGNATURE_ALGORITHMS, CURLOPTTYPE_STRINGPOINT, 328),
 
+  /* prevent transparent retries on a new connection when a previously
+   * reused connection was reset or otherwise no longer unavailable. */
+  CURLOPT(CURLOPT_FORBID_RETRY_ON_REUSE, CURLOPTTYPE_LONG, 329),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 

lib/easyoptions.c

@@ -97,6 +97,7 @@ const struct curl_easyoption Curl_easyopts[] = {
   {"FNMATCH_DATA", CURLOPT_FNMATCH_DATA, CURLOT_CBPTR, 0},
   {"FNMATCH_FUNCTION", CURLOPT_FNMATCH_FUNCTION, CURLOT_FUNCTION, 0},
   {"FOLLOWLOCATION", CURLOPT_FOLLOWLOCATION, CURLOT_LONG, 0},
+  {"FORBID_RETRY_ON_REUSE", CURLOPT_FORBID_RETRY_ON_REUSE, CURLOT_LONG, 0},
   {"FORBID_REUSE", CURLOPT_FORBID_REUSE, CURLOT_LONG, 0},
   {"FRESH_CONNECT", CURLOPT_FRESH_CONNECT, CURLOT_LONG, 0},
   {"FTPAPPEND", CURLOPT_APPEND, CURLOT_LONG, CURLOT_FLAG_ALIAS},
@@ -380,6 +381,6 @@ const struct curl_easyoption Curl_easyopts[] = {
  */
 int Curl_easyopts_check(void)
 {
-  return (CURLOPT_LASTENTRY % 10000) != (328 + 1);
+  return (CURLOPT_LASTENTRY % 10000) != (329 + 1);
 }
 #endif

lib/setopt.c

@@ -452,6 +452,13 @@ static CURLcode setopt_bool(struct Curl_easy *data, CURLoption option,
      */
     s->reuse_forbid = enabled;
     break;
+  case CURLOPT_FORBID_RETRY_ON_REUSE:
+    /**
+     * No retry under any circumstances even when a reset happens on a reused
+     * connection.
+     */
+    s->retry_on_reuse_forbid = enabled;
+    break;
   case CURLOPT_FRESH_CONNECT:
     /*
      * This transfer shall not use a previously cached connection but

lib/transfer.c

@@ -667,7 +667,7 @@ CURLcode Curl_retry_request(struct Curl_easy *data, char **url)
     return CURLE_OK;
 
   if((data->req.bytecount + data->req.headerbytecount == 0) &&
-     conn->bits.reuse &&
+     conn->bits.reuse && conn->bits.retry_on_reuse &&
      (!data->req.no_body || (conn->handler->protocol & PROTO_FAMILY_HTTP))
 #ifndef CURL_DISABLE_RTSP
      && (data->set.rtspreq != RTSPREQ_RECEIVE)

lib/url.c

@@ -3514,6 +3514,10 @@ static CURLcode create_conn(struct Curl_easy *data,
    *************************************************************/
   if((conn->given->flags&PROTOPT_SSL) && conn->bits.httpproxy)
     conn->bits.tunnel_proxy = TRUE;
+
+  /* Carry over the no-retry-on-reuse into connection bits. */
+  conn->bits.retry_on_reuse = !data->set.retry_on_reuse_forbid;
+
 #endif
 
   /*************************************************************

lib/urldata.h

@@ -379,6 +379,8 @@ struct ConnectBits {
   /* always modify bits.close with the connclose() and connkeep() macros! */
   BIT(close); /* if set, we close the connection after this request */
   BIT(reuse); /* if set, this is a reused connection */
+  BIT(retry_on_reuse); /* if set, a reused connection after connection reset
+                          is allowed to retry the request */
   BIT(altused); /* this is an alt-svc "redirect" */
   BIT(conn_to_host); /* if set, this connection has a "connect to host"
                         that overrides the host in the URL */
@@ -1605,6 +1607,7 @@ struct UserDefined {
 #endif
   BIT(reuse_forbid);   /* forbidden to be reused, close after use */
   BIT(reuse_fresh);    /* do not reuse an existing connection  */
+  BIT(retry_on_reuse_forbid);   /* do not retry under connection reset */
   BIT(no_signal);      /* do not use any signal/alarm handler */
   BIT(tcp_nodelay);    /* whether to enable TCP_NODELAY or not */
   BIT(ignorecl);       /* ignore content length */

src/tool_operate.c

@@ -1398,6 +1398,8 @@ static CURLcode add_parallel_transfers(CURLM *multi, CURLSH *share,
 #ifdef DEBUGBUILD
     if(getenv("CURL_FORBID_REUSE"))
       (void)curl_easy_setopt(per->curl, CURLOPT_FORBID_REUSE, 1L);
+    if(getenv("CURL_FORBID_RETRY_ON_REUSE"))
+      (void)curl_easy_setopt(per->curl, CURLOPT_FORBID_RETRY_ON_REUSE, 1L);
 #endif
 
     mcode = curl_multi_add_handle(multi, per->curl);
@@ -1868,6 +1870,8 @@ static CURLcode serial_transfers(CURLSH *share)
 #ifdef DEBUGBUILD
       if(getenv("CURL_FORBID_REUSE"))
         (void)curl_easy_setopt(per->curl, CURLOPT_FORBID_REUSE, 1L);
+      if(getenv("CURL_FORBID_RETRY_ON_REUSE"))
+        (void)curl_easy_setopt(per->curl, CURLOPT_FORBID_RETRY_ON_REUSE, 1L);
 
       if(global->test_duphandle) {
         CURL *dup = curl_easy_duphandle(per->curl);

src/tool_urlglob.c

@@ -423,10 +423,13 @@ static CURLcode glob_parse(struct URLGlob *glob, const char *pattern,
     if(++glob->size >= glob->palloc) {
       struct URLPattern *np = NULL;
       glob->palloc *= 2;
-      if(glob->size < 10000) /* avoid ridiculous amounts */
+      if(glob->size < 255) { /* avoid ridiculous amounts */
         np = realloc(glob->pattern, glob->palloc * sizeof(struct URLPattern));
-      if(!np)
-        return globerror(glob, NULL, pos, CURLE_OUT_OF_MEMORY);
+        if(!np)
+          return globerror(glob, NULL, pos, CURLE_OUT_OF_MEMORY);
+      }
+      else
+        return globerror(glob, "too many {} sets", pos, CURLE_URL_MALFORMAT);
       glob->pattern = np;
     }
   }

tests/data/Makefile.am

@@ -108,7 +108,7 @@ test718 test719 test720 test721 test722 test723 test724 test725 test726 \
 test727 test728 test729 test730 test731 test732 test733 test734 test735 \
 test736 test737 test738 test739 test740 test741 test742 test743 test744 \
 test745 test746 test747 test748 test749 test750 test751 test752 test753 \
-test754 test755 test756 test757 test758 test759 test760 \
+test754 test755 test756 test757 test758 test759 test760 test761 \
 test780 test781 test782 test783 test784 test785 test786 test787 test788 \
 test789 test790 test791 test792 test793 test794 test795 test796 test797 \
 \

tests/data/test761

@@ -0,0 +1,33 @@
+<testcase>
+<info>
+<keywords>
+globbing
+</keywords>
+</info>
+
+#
+# Client-side
+<client>
+<server>
+none
+</server>
+<name>
+too many {} globs
+</name>
+<command>
+http://testingthis/{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<errorcode>
+3
+</errorcode>
+<stderr mode="text">
+curl: (3) too many {} sets in URL position 403:
+http://testingthis/{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a}b{a
+</stderr>
+</verify>
+</testcase>