The librest build has this warning which is not as harmless as it might appear:
  CC       librest_0.7_la-oauth-proxy-call.lo
oauth-proxy-call.c: In function 'sign_hmac':
oauth-proxy-call.c:130:3: warning: implicit declaration of function 'rest_proxy_call_get_url' [-Wimplicit-function-declaration]
   url_str = rest_proxy_call_get_url (call);
   ^
oauth-proxy-call.c:130:11: warning: assignment makes pointer from integer without a cast
   url_str = rest_proxy_call_get_url (call);
           ^
The compiler assumes int as the return type, but in reality it returns a pointer. Using the function without a prototype will lead to memory errors when the size of an int is not the same as a pointer.

You can trigger a crash by running the EnsureCredentials method from the org.gnome.OnlineAccounts.Account interface on an object representing a Flickr account.


Program received signal SIGSEGV, Segmentation fault.

+ Trace 234534

124	  GHashTable *all_params;
125	  RestParamsIter params_iter;
126	  RestParam *param;
127	  gboolean encode_query_params = TRUE;
128	
129	  priv = PROXY_GET_PRIVATE (proxy);
130	  url_str = rest_proxy_call_get_url (call);
131	
132	  text = g_string_new (NULL);
133	  g_string_append (text, rest_proxy_call_get_method (REST_PROXY_CALL (call)));
(gdb) 
134	  g_string_append_c (text, '&');
135	  if (priv->oauth_echo) {
136	    g_string_append_uri_escaped (text, priv->service_url, NULL, FALSE);
137	  } else if (priv->signature_host != NULL) {
138	    SoupURI *url = soup_uri_new (url_str);
139	    gchar *signing_url;
140	
141	    soup_uri_set_host (url, priv->signature_host);
142	    signing_url = soup_uri_to_string (url, FALSE);
143	
(gdb) 
144	    g_string_append_uri_escaped (text, signing_url, NULL, FALSE);
145	
146	    soup_uri_free (url);
147	    g_free (signing_url);
148	  } else {
149	    g_string_append_uri_escaped (text, url_str, NULL, FALSE);
150	  }
151	  g_string_append_c (text, '&');
152	
153	
(gdb) print url_str
$1 = 0xffffffffe831ba70 <error: Cannot access memory at address 0xffffffffe831ba70>
(gdb) print *call
$2 = {parent = {g_type_instance = {g_class = 0x7f1ee8552400}, ref_count = 1, qdata = 0x0}, priv = 0x7f1edc00e310}
(gdb) print *(call->priv)
$3 = {method = 0x7f1ee82ea960 "GET", function = 0x0, headers = 0x7f1ee84f15e0, params = 0x7f1ee84f1640, 
  url = 0x7f1ee831ba70 "https://api.flickr.com/services/rest", response_headers = 0x7f1eec058400, length = 0, 
  payload = 0x0, status_code = 0, status_message = 0x0, cancellable = 0x0, cancel_sig = 0, 
  proxy = 0x6bf6e0 [OAuthProxy], cur_call_closure = 0x0}
(gdb)