#29 do not double callback on throw

src/service.js

@@ -117,7 +117,9 @@ let Service = function Service (Transports, config) {
 
         if (response && typeof response.then === 'function') {
           callbackHandler = null
-          return response.then(finish).catch(cb)
+          return response.then(finish, cb)
+          // if an exception was thrown from finish(), let it bubble up
+          // as an unhandled rejection, rather than also call cb()
         }
       }
     })

test/z-integration.js

@@ -0,0 +1,39 @@
+
+"use strict";
+
+const assert   = require('assert');
+const s        = require('ht-schema');
+const bluebird = require('bluebird');
+
+const Service = require('../src/service');
+const Client  = require('../src/client');
+const Transports = require('../src/transports');
+
+describe("Integrations", function () {
+  it("does not double call when callback throws", function (done) {
+    var transport = new Transports.Local();
+    var service = new Service(transport);
+    var client = new Client({ s: transport });
+
+    let countCalled = 0
+
+    service.on("hello", null, function () {
+      return new Promise(function (resolve, reject) { 
+        resolve('hello')
+      })
+    })
+
+    client.call('s', 'hello', function (err, result) {
+      countCalled++
+      throw Error('oops')
+    })
+
+    setTimeout(function () {
+      switch (countCalled) {
+        case 0: throw Error('did not get called at all')
+        case 1: return done()
+        case 2: throw Error('called multiple times')
+      }
+    }, 100)
+  });
+});