From 5de53960f91fce7589ce498c98e561639e9aabbb Mon Sep 17 00:00:00 2001
From: Brian Flad <bflad417@gmail.com>
Date: Tue, 8 Oct 2019 11:39:34 -0400
Subject: [PATCH] helper/schema: Do not collapse TypeSet hash values when
 configuration block contains only Computed attributes

Reference: https://github.com/terraform-providers/terraform-provider-aws/issues/7198
Reference: https://github.com/terraform-providers/terraform-provider-aws/pull/10045
Reference: https://github.com/terraform-providers/terraform-provider-aws/pull/10339
Reference: https://github.com/hashicorp/terraform/pull/22719

When a resource schema contains the following:

```go
"config_block_attribute": {
	Type:     schema.TypeSet,
	Computed: true,
	Elem: &schema.Resource{
		Schema: map[string]*schema.Schema{
			"attribute1": {
				Type:     schema.TypeBool,
				Computed: true,
			},
			"attribute2": {
				Type:     schema.TypeString,
				Computed: true,
			},
		},
	},
},
```

The TypeSet hash values were previously all collapsed to the zero-value, which meant that multiple set entries were lost. Here we check that all of the attributes are not just `Computed: true`. If they are all `Computed: true` attributes, ignore the check for user-defined attributes to compute the hash value.
---
 helper/schema/serialize.go      |  9 +++++++--
 helper/schema/serialize_test.go | 20 ++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/helper/schema/serialize.go b/helper/schema/serialize.go
index fe6d7504c74..0e0e3cca9e5 100644
--- a/helper/schema/serialize.go
+++ b/helper/schema/serialize.go
@@ -91,7 +91,12 @@ func SerializeResourceForHash(buf *bytes.Buffer, val interface{}, resource *Reso
 	sm := resource.Schema
 	m := val.(map[string]interface{})
 	var keys []string
-	for k := range sm {
+	allComputed := true
+	for k, v := range sm {
+		if v.Optional || v.Required {
+			allComputed = false
+		}
+
 		keys = append(keys, k)
 	}
 	sort.Strings(keys)
@@ -100,7 +105,7 @@ func SerializeResourceForHash(buf *bytes.Buffer, val interface{}, resource *Reso
 		// Skip attributes that are not user-provided. Computed attributes
 		// do not contribute to the hash since their ultimate value cannot
 		// be known at plan/diff time.
-		if !(innerSchema.Required || innerSchema.Optional) {
+		if !allComputed && !(innerSchema.Required || innerSchema.Optional) {
 			continue
 		}
 
diff --git a/helper/schema/serialize_test.go b/helper/schema/serialize_test.go
index 55afb1528f7..c5480272038 100644
--- a/helper/schema/serialize_test.go
+++ b/helper/schema/serialize_test.go
@@ -217,6 +217,26 @@ func TestSerializeForHash(t *testing.T) {
 			},
 			Expected: "outer:{[baz:foo;foo:bar;];};",
 		},
+
+		testCase{
+			Schema: &Resource{
+				Schema: map[string]*Schema{
+					"attr1": &Schema{
+						Type:     TypeString,
+						Computed: true,
+					},
+					"attr2": &Schema{
+						Type:     TypeString,
+						Computed: true,
+					},
+				},
+			},
+			Value: map[string]interface{}{
+				"attr1": "value1",
+				"attr2": "value2",
+			},
+			Expected: "attr1:value1;attr2:value2;",
+		},
 	}
 
 	for _, test := range tests {