fix(@embark/core): Allow errors in event actions

Add the ability to pass an error in the callback of an event action.

Currently, event actions could either pass back a an error OR a result, but not both, and with no way to distinguish between the two parameters. This PR adds the ability to pass an error as the first parameter of the action callback.

An example of a use case that this fixed: errors on `deployIf` were silently swallowed, which has now been fixed.

All instances of `events.request(“deploy:contracts”)` were given an `error` parameter in their callback, and errors printed if it is not undefined.

All instances of `registerActionForEvent` were combed to ensure any callbacks were passing the expected error and result.

packages/embark/src/cmd/cmd_controller.js

@@ -136,7 +136,7 @@ class EmbarkController {
           engine.config.reloadConfig();
           engine.events.request('deploy:contracts', function (err) {
             if (err) {
-              return;
+              return engine.logger.error(err.message || err);
             }
             engine.logger.info(__('Deployment Done'));
           });
@@ -251,7 +251,10 @@ class EmbarkController {
           callback(err, true);
         });
       }
-    ], function (_err, canExit) {
+    ], function (err, canExit) {
+      if(err) {
+        engine.logger.error(err.message || err);
+      }
       // TODO: this should be moved out and determined somewhere else
       if (canExit || !engine.config.contractsConfig.afterDeploy || !engine.config.contractsConfig.afterDeploy.length) {
         process.exit();
@@ -562,7 +565,7 @@ class EmbarkController {
           engine.config.reloadConfig();
           engine.events.request('deploy:contracts', function (err) {
             if (err) {
-              return;
+              return engine.logger.error(err.message || err);
             }
             engine.logger.info(__('Deployment Done'));
           });

packages/embark/src/lib/core/engine.js

@@ -246,7 +246,11 @@ class Engine {
         // TODO: for now need to deploy on asset changes as well
         // because the contractsManager config is corrupted after a deploy
         if (fileType === 'contract' || fileType === 'config') {
-          self.events.request('deploy:contracts', () => {});
+          self.events.request('deploy:contracts', (err) => {
+            if (err) {
+              self.logger.error(err.message || err);
+            }
+          });
         }
       }, 50);
     });

packages/embark/src/lib/core/plugins.js

@@ -163,12 +163,12 @@ Plugins.prototype.runActionsForEvent = function(eventName, args, cb) {
 
   async.reduce(actionPlugins, args, function(current_args, plugin, nextEach) {
     if (typeof (args) === 'function') {
-      plugin.call(plugin, (params) => {
+      plugin.call(plugin, (...params) => {
-        nextEach(null, (params || current_args));
+        nextEach(...params || current_args);
       });
     } else {
-      plugin.call(plugin, args, (params) => {
+      plugin.call(plugin, args, (...params) => {
-        nextEach(null, (params || current_args));
+        nextEach(...params || current_args);
       });
     }
   }, cb);

packages/embark/src/lib/modules/deploytracker/index.js

@@ -42,7 +42,7 @@ class DeployTracker {
 
     self.embark.registerActionForEvent("deploy:contract:shouldDeploy", (params, cb) => {
       if (!self.trackContracts) {
-        return cb(params);
+        return cb(null, params);
       }
 
       let contract = params.contract;
@@ -53,7 +53,7 @@ class DeployTracker {
       if (params.shouldDeploy && trackedContract) {
          params.shouldDeploy = true;
       }
-      cb(params);
+      cb(null, params);
     });
   }
 
@@ -63,7 +63,10 @@ class DeployTracker {
       this.currentChain = {contracts: []};
       return cb();
     }
-    this.events.request("blockchain:block:byNumber", 0, function(_err, block) {
+    this.events.request("blockchain:block:byNumber", 0, function(err, block) {
+      if (err) {
+        return cb(err);
+      }
       let chainId = block.hash;
 
       if (self.chainConfig[chainId] === undefined) {

packages/embark/src/lib/modules/specialconfigs/index.js

@@ -189,14 +189,14 @@ class SpecialConfigs {
       let cmd = params.contract.deployIf;
       const contract = params.contract;
       if (!cmd) {
-        return cb(params);
+        return cb(null, params);
       }
 
       if (typeof cmd === 'function') {
         try {
           const dependencies = await this.getOnDeployLifecycleHookDependencies(contract);
           params.shouldDeploy = await contract.deployIf(dependencies);
-          cb(params);
+          cb(null, params);
         } catch (err) {
           return cb(new Error(`Error when registering deployIf hook for ${contract.name}: ${err.message}`));
         }
@@ -212,7 +212,7 @@ class SpecialConfigs {
             params.shouldDeploy = false;
           }
 
-          cb(params);
+          cb(null, params);
         });
       }
     });

packages/embark/src/lib/modules/tests/test.js

@@ -295,8 +295,8 @@ class Test {
         });
       },
       function deploy(accounts, web3, next) {
-        self.events.request('deploy:contracts:test', () => {
+        self.events.request('deploy:contracts:test', (err) => {
-          next(null, accounts, web3);
+          next(err, accounts, web3);
         });
       },
       function waitForProvidersReady(accounts, web3, next) {