From 202b0aef1ba02f0beae945acc802adcd10073197 Mon Sep 17 00:00:00 2001
From: Radek Simko <radek.simko@gmail.com>
Date: Thu, 17 Dec 2015 17:01:31 +0100
Subject: [PATCH 1/2] provider/aws: Always use either body or URL for all
 updates

 - fixes #4332
---
 .../providers/aws/resource_aws_cloudformation_stack.go | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/builtin/providers/aws/resource_aws_cloudformation_stack.go b/builtin/providers/aws/resource_aws_cloudformation_stack.go
index 1846a3105..86dd8bdb7 100644
--- a/builtin/providers/aws/resource_aws_cloudformation_stack.go
+++ b/builtin/providers/aws/resource_aws_cloudformation_stack.go
@@ -258,12 +258,14 @@ func resourceAwsCloudFormationStackUpdate(d *schema.ResourceData, meta interface
 		StackName: aws.String(d.Get("name").(string)),
 	}
 
-	if d.HasChange("template_body") {
-		input.TemplateBody = aws.String(normalizeJson(d.Get("template_body").(string)))
+	// Either TemplateBody or TemplateURL are required for each change
+	if v, ok := d.GetOk("template_body"); ok {
+		input.TemplateBody = aws.String(normalizeJson(v.(string)))
 	}
-	if d.HasChange("template_url") {
-		input.TemplateURL = aws.String(d.Get("template_url").(string))
+	if v, ok := d.GetOk("template_url"); ok {
+		input.TemplateURL = aws.String(v.(string))
 	}
+
 	if d.HasChange("capabilities") {
 		input.Capabilities = expandStringList(d.Get("capabilities").(*schema.Set).List())
 	}

From 4e408d1593903e94a1fd2d2718909f6aed752890 Mon Sep 17 00:00:00 2001
From: Radek Simko <radek.simko@gmail.com>
Date: Thu, 17 Dec 2015 17:58:43 +0100
Subject: [PATCH 2/2] provider/aws: CloudFormation - Add regression test for
 #4332

---
 .../resource_aws_cloudformation_stack_test.go | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/builtin/providers/aws/resource_aws_cloudformation_stack_test.go b/builtin/providers/aws/resource_aws_cloudformation_stack_test.go
index 0c99f8d54..19b6f6c52 100644
--- a/builtin/providers/aws/resource_aws_cloudformation_stack_test.go
+++ b/builtin/providers/aws/resource_aws_cloudformation_stack_test.go
@@ -64,6 +64,31 @@ func TestAccAWSCloudFormation_allAttributes(t *testing.T) {
 	})
 }
 
+// Regression for https://github.com/hashicorp/terraform/issues/4332
+func TestAccAWSCloudFormation_withParams(t *testing.T) {
+	var stack cloudformation.Stack
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSCloudFormationDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAWSCloudFormationConfig_withParams,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckCloudFormationStackExists("aws_cloudformation_stack.with_params", &stack),
+				),
+			},
+			resource.TestStep{
+				Config: testAccAWSCloudFormationConfig_withParams_modified,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckCloudFormationStackExists("aws_cloudformation_stack.with_params", &stack),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckCloudFormationStackExists(n string, stack *cloudformation.Stack) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		rs, ok := s.RootModule().Resources[n]
@@ -225,3 +250,43 @@ resource "aws_sns_topic" "cf-updates" {
   name = "tf-cf-notifications"
 }
 `
+
+var tpl_testAccAWSCloudFormationConfig_withParams = `
+resource "aws_cloudformation_stack" "with_params" {
+  name = "tf-stack-with-params"
+  parameters {
+    VpcCIDR = "%s"
+  }
+  template_body = <<STACK
+{
+  "Parameters" : {
+    "VpcCIDR" : {
+      "Description" : "CIDR to be used for the VPC",
+      "Type" : "String"
+    }
+  },
+  "Resources" : {
+    "MyVPC": {
+      "Type" : "AWS::EC2::VPC",
+      "Properties" : {
+        "CidrBlock" : {"Ref": "VpcCIDR"},
+        "Tags" : [
+          {"Key": "Name", "Value": "Primary_CF_VPC"}
+        ]
+      }
+    }
+  }
+}
+STACK
+
+  on_failure = "DELETE"
+  timeout_in_minutes = 1
+}
+`
+
+var testAccAWSCloudFormationConfig_withParams = fmt.Sprintf(
+	tpl_testAccAWSCloudFormationConfig_withParams,
+	"10.0.0.0/16")
+var testAccAWSCloudFormationConfig_withParams_modified = fmt.Sprintf(
+	tpl_testAccAWSCloudFormationConfig_withParams,
+	"12.0.0.0/16")