Downgrade an assert to LD_BUG

This should prevent crashes on further recurrence of 8065, and help
diagnose such if they occur

changes/bug8065

@@ -0,0 +1,6 @@
+  o Minor bugfixes:
+    - Downgrade an assertion in connection_ap_expire_beginning to
+      an LD_BUG message. The fix for bug 8024 should prevent this
+      message from displaying, but just in case a warn that we can
+      diagnose is better than more assert crashes. Fix for bug 8065;
+      bugfix on 0.2.4.8-alpha.

src/or/circuitbuild.c

@@ -1269,7 +1269,7 @@ pathbias_get_scale_use_threshold(const or_options_t *options)
 /**
  * Convert a Guard's path state to string.
  */
-static const char *
+const char *
 pathbias_state_to_string(path_state_t state)
 {
   switch (state) {

src/or/circuitbuild.h

@@ -66,6 +66,7 @@ int pathbias_check_probe_response(circuit_t *circ, const cell_t *cell);
 void pathbias_count_use_attempt(origin_circuit_t *circ);
 void pathbias_mark_use_success(origin_circuit_t *circ);
 void pathbias_mark_use_rollback(origin_circuit_t *circ);
+const char *pathbias_state_to_string(path_state_t state);
 
 #endif
 

src/or/connection_edge.c

@@ -651,7 +651,16 @@ connection_ap_expire_beginning(void)
       }
       continue;
     }
-    tor_assert(circ->purpose == CIRCUIT_PURPOSE_C_GENERAL);
+    if (circ->purpose != CIRCUIT_PURPOSE_C_GENERAL) {
+      log_warn(LD_BUG, "circuit->purpose == CIRCUIT_PURPOSE_C_GENERAL failed. "
+               "The purpose on the circuit was %s; it was in state %s, "
+               "path_state %s.",
+               circuit_purpose_to_string(circ->purpose),
+               circuit_state_to_string(circ->state),
+               CIRCUIT_IS_ORIGIN(circ) ?
+                 pathbias_state_to_string(TO_ORIGIN_CIRCUIT(circ)->path_state) :
+                 "none");
+    }
     log_fn(cutoff < 15 ? LOG_INFO : severity, LD_APP,
            "We tried for %d seconds to connect to '%s' using exit %s."
            " Retrying on a new circuit.",