From 4dbe6add77f0eb912cbd1030047395ffa7ada8c5 Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Mon, 8 Apr 2019 15:33:35 -0400
Subject: [PATCH] Revert "helper/schema: Schema.AsSingle flag"

This reverts commit 4c0c74571de9c96ad2902ccf4af962ec495cd5d4.
---
 helper/schema/schema.go      | 22 -------------
 helper/schema/schema_test.go | 62 ------------------------------------
 2 files changed, 84 deletions(-)

diff --git a/helper/schema/schema.go b/helper/schema/schema.go
index 15a82e7f7..56f2930fc 100644
--- a/helper/schema/schema.go
+++ b/helper/schema/schema.go
@@ -216,21 +216,8 @@ type Schema struct {
 	//
 	// If the field Optional is set to true then MinItems is ignored and thus
 	// effectively zero.
-	//
-	// If MaxItems is 1, you may optionally also set AsSingle in order to have
-	// Terraform v0.12 or later treat a TypeList or TypeSet as if it were a
-	// single value. It will remain a list or set in Terraform v0.10 and v0.11.
-	// Enabling this for an existing attribute after you've made at least one
-	// v0.12-compatible provider release is a breaking change. AsSingle is
-	// likely to misbehave when used with deeply-nested set structures due to
-	// the imprecision of set diffs, so be sure to test it thoroughly,
-	// including updates that change the set members at all levels. AsSingle
-	// exists primarily to be used in conjunction with ConfigMode when forcing
-	// a nested resource to be treated as an attribute, so it can be considered
-	// an attribute of object type rather than of list/set of object.
 	MaxItems int
 	MinItems int
-	AsSingle bool
 
 	// PromoteSingle originally allowed for a single element to be assigned
 	// where a primitive list was expected, but this no longer works from
@@ -863,15 +850,6 @@ func (m schemaMap) internalValidate(topSchemaMap schemaMap, attrsOnly bool) erro
 			}
 		}
 
-		if v.AsSingle {
-			if v.MaxItems != 1 {
-				return fmt.Errorf("%s: MaxItems must be 1 when AsSingle is set", k)
-			}
-			if v.Type != TypeList && v.Type != TypeSet {
-				return fmt.Errorf("%s: AsSingle can be used only with TypeList and TypeSet schemas", k)
-			}
-		}
-
 		// Computed-only field
 		if v.Computed && !v.Optional {
 			if v.ValidateFunc != nil {
diff --git a/helper/schema/schema_test.go b/helper/schema/schema_test.go
index 327a4e343..4f8d9dd61 100644
--- a/helper/schema/schema_test.go
+++ b/helper/schema/schema_test.go
@@ -3924,68 +3924,6 @@ func TestSchemaMap_InternalValidate(t *testing.T) {
 			},
 			true, // in *schema.Resource with ConfigMode of attribute, so must also have ConfigMode of attribute
 		},
-
-		"AsSingle okay": {
-			map[string]*Schema{
-				"block": &Schema{
-					Type:     TypeList,
-					Optional: true,
-					MaxItems: 1,
-					AsSingle: true,
-					Elem: &Resource{
-						Schema: map[string]*Schema{
-							"sub": &Schema{
-								Type:     TypeList,
-								Optional: true,
-								Elem:     &Resource{},
-							},
-						},
-					},
-				},
-			},
-			false,
-		},
-
-		"AsSingle without MaxItems": {
-			map[string]*Schema{
-				"block": &Schema{
-					Type:     TypeList,
-					Optional: true,
-					AsSingle: true,
-					Elem: &Resource{
-						Schema: map[string]*Schema{
-							"sub": &Schema{
-								Type:     TypeList,
-								Optional: true,
-								Elem:     &Resource{},
-							},
-						},
-					},
-				},
-			},
-			true, // MaxItems must be 1 when AsSingle is set
-		},
-
-		"AsSingle on primitive type": {
-			map[string]*Schema{
-				"block": &Schema{
-					Type:     TypeString,
-					Optional: true,
-					MaxItems: 1,
-					AsSingle: true,
-					Elem: &Resource{
-						Schema: map[string]*Schema{
-							"sub": &Schema{
-								Type:     TypeList,
-								Optional: true,
-								Elem:     &Resource{},
-							},
-						},
-					},
-				},
-			},
-			true, // Unexpected error occurred: block: MaxItems and MinItems are only supported on lists or sets
-		},
 	}
 
 	for tn, tc := range cases {