Tweak

src/libstore/download.cc

@@ -98,11 +98,7 @@ struct CurlDownloader : public Downloader
         {
             assert(!done);
             done = true;
-            try {
+            callFailure(failure, std::make_exception_ptr(e));
-                throw e;
-            } catch (...) {
-                callFailure(failure);
-            }
         }
 
         size_t writeCallback(void * contents, size_t size, size_t nmemb)

src/libutil/util.cc

@@ -1230,10 +1230,10 @@ string base64Decode(const string & s)
 }
 
 
-void callFailure(const std::function<void(std::exception_ptr exc)> & failure)
+void callFailure(const std::function<void(std::exception_ptr exc)> & failure, std::exception_ptr exc)
 {
     try {
-        failure(std::current_exception());
+        failure(exc);
     } catch (std::exception & e) {
         printMsg(lvlError, format("uncaught exception: %s") % e.what());
         abort();

src/libutil/util.hh

@@ -383,7 +383,8 @@ string get(const T & map, const string & key, const string & def = "")
 
 /* Call ‘failure’ with the current exception as argument. If ‘failure’
    throws an exception, abort the program. */
-void callFailure(const std::function<void(std::exception_ptr exc)> & failure);
+void callFailure(const std::function<void(std::exception_ptr exc)> & failure,
+    std::exception_ptr exc = std::current_exception());
 
 
 /* Evaluate the function ‘f’. If it returns a value, call ‘success’