Use region and stage from the provider.

index.js

@@ -7,12 +7,16 @@ const setBucketName = require('serverless/lib/plugins/aws/lib/setBucketName')
 class ServerlessCloudFormationChangeSets {
   constructor (serverless, options) {
     this.serverless = serverless
+    this.provider = this.serverless.getProvider('aws')
     this.options = _.merge(
       {},
       _.omit(options, ['changeset']),
-      _.get(serverless.service, 'custom.cf-changesets') || {}
+      _.get(serverless.service, 'custom.cf-changesets') || {},
+      {
+        region: this.provider.getRegion(),
+        stage: this.provider.getStage()
+      }
     )
-    this.provider = this.serverless.getProvider('aws')
 
     if (options.changeset) {
       this.options.requireChangeSet = true

index.test.js

@@ -31,6 +31,15 @@ describe('ServerlessCloudFormationChangeSets', () => {
       expect(serverlessChangeSets.serverless).to.equal(serverless)
     })
 
+    it('should get options even when no options are passed in', () => {
+      // _.set(serverless, 'service.custom.cf-changesets.changeSetName', 'test')
+      const serverlessChangeSets = new ServerlessCloudFormationChangeSets(serverless, {})
+      expect(serverlessChangeSets.options).to.deep.equal({
+        stage: 'dev',
+        region: 'us-east-1'
+      })
+    })
+
     it('should set options from CLI command', () => {
       expect(serverlessChangeSets.options).to.deep.equal({
         stage: 'dev',

lib/createChangeSet.js

@@ -14,6 +14,9 @@ const createChangeSet = (plugin, stackName, changeSetName, changeSetType) => {
     stackTags = _.extend(stackTags, plugin.serverless.service.provider.stackTags)
   }
 
+  // Filter tags that do not have a value.
+  stackTags = _.pickBy(stackTags)
+
   const params = {
     StackName: stackName,
     ChangeSetName: changeSetName,

lib/createChangeSet.test.js

@@ -92,6 +92,17 @@ describe('updateStack', () => {
         })
     })
 
+    it('should exclude stack tags that have no value', () => {
+      serverlessChangeSets.serverless.service.provider.stackTags = { STAGE: undefined, tag1: null, hasValue: 'bob' }
+
+      return createChangeSet.bind(serverlessChangeSets)().then(() => {
+        expect(createChangeSetStub.args[0][2].Tags)
+          .to.deep.equal([
+            { Key: 'hasValue', Value: 'bob' }
+          ])
+      })
+    })
+
     it('should include custom stack tags and CF service role', () => {
       serverlessChangeSets.serverless.service.provider.stackTags = { STAGE: 'overridden', tag1: 'value1' }
       serverlessChangeSets.serverless.service.provider.cfnRole = 'arn:aws:iam::123456789012:role/myrole'