url: Improve CURLOPT_PROXY_CAPATH error handling

- Change CURLOPT_PROXY_CAPATH to return CURLE_NOT_BUILT_IN if the option
  is not supported, which is the same as what we already do for
  CURLOPT_CAPATH.

- Change the curl tool to handle CURLOPT_PROXY_CAPATH error
  CURLE_NOT_BUILT_IN as a warning instead of as an error, which is the
  same as what we already do for CURLOPT_CAPATH.

- Fix CAPATH docs to show that CURLE_NOT_BUILT_IN is returned when the
  respective CAPATH option is not supported by the SSL library.

Ref: https://github.com/curl/curl/pull/1257

1 files changed, 17 insertions, 4 deletions

diff --git a/src/tool_operate.c b/src/tool_operate.c
index bc36520d9..c30b32046 100644
--- a/src/tool_operate.c
+++ b/src/tool_operate.c
@@ -1014,6 +1014,7 @@ static CURLcode operate_do(struct GlobalConfig *global,
           my_setopt_str(curl, CURLOPT_CAINFO, config->cacert);
         if(config->proxy_cacert)
           my_setopt_str(curl, CURLOPT_PROXY_CAINFO, config->proxy_cacert);
+
         if(config->capath) {
           result = res_setopt_str(curl, CURLOPT_CAPATH, config->capath);
           if(result == CURLE_NOT_BUILT_IN) {
@@ -1024,10 +1025,22 @@ static CURLcode operate_do(struct GlobalConfig *global,
           else if(result)
             goto show_error;
         }
-        if(config->proxy_capath)
-          my_setopt_str(curl, CURLOPT_PROXY_CAPATH, config->proxy_capath);
-        else if(config->capath) /* CURLOPT_PROXY_CAPATH default is capath */
-          my_setopt_str(curl, CURLOPT_PROXY_CAPATH, config->capath);
+        /* For the time being if --proxy-capath is not set then we use the
+           --capath value for it, if any. See #1257 */
+        if(config->proxy_capath || config->capath) {
+          result = res_setopt_str(curl, CURLOPT_PROXY_CAPATH,
+                                  (config->proxy_capath ?
+                                   config->proxy_capath :
+                                   config->capath));
+          if(result == CURLE_NOT_BUILT_IN) {
+            if(config->proxy_capath) {
+              warnf(config->global,
+                    "ignoring --proxy-capath, not supported by libcurl\n");
+            }
+          }
+          else if(result)
+            goto show_error;
+        }
 
         if(config->crlfile)
           my_setopt_str(curl, CURLOPT_CRLFILE, config->crlfile);