command/013upgrade: detect builtin terraform provider (#25215)

* command/013upgrade: detect builtin terraform provider

command/013_config_upgrade.go

@@ -240,6 +240,11 @@ command and dealing with them before running this command again.
 	for _, file := range files {
 		// Step 2: add missing provider requirements from provider blocks
 		for _, p := range file.ProviderConfigs {
+			// Skip internal providers
+			if p.Name == "terraform" {
+				continue
+			}
+
 			// If no explicit provider configuration exists for the
 			// provider configuration's local name, add one with a legacy
 			// provider address.
@@ -266,6 +271,11 @@ command and dealing with them before running this command again.
 					localName = r.Addr().ImpliedProvider()
 				}
 
+				// Skip internal providers
+				if localName == "terraform" {
+					continue
+				}
+
 				// If no explicit provider configuration exists for this local
 				// name, add one with a legacy provider address.
 				if _, exist := requiredProviders[localName]; !exist {

command/testdata/013upgrade-explicit-providers/expected/main.tf

@@ -1,4 +1,4 @@
-provider foo {
+provider "foo" {
   version = "1.2.3"
 }
 
@@ -17,3 +17,5 @@ terraform {
     }
   }
 }
+
+provider "terraform" {}

command/testdata/013upgrade-explicit-providers/input/main.tf

@@ -1,4 +1,4 @@
-provider foo {
+provider "foo" {
   version = "1.2.3"
 }
 
@@ -10,3 +10,5 @@ terraform {
     }
   }
 }
+
+provider "terraform" { }

command/testdata/013upgrade-implicit-providers/expected/main.tf

@@ -1,5 +1,6 @@
-resource foo_resource b {}
-resource bar_resource c {}
-resource bar_resource ab {
+resource "foo_resource" "b" {}
+resource "bar_resource" "c" {}
+resource "bar_resource" "ab" {
   provider = baz
 }
+resource "terraform_remote_state" "production" {}

command/testdata/013upgrade-implicit-providers/input/main.tf

@@ -1,5 +1,6 @@
-resource foo_resource b {}
-resource bar_resource c {}
-resource bar_resource ab {
+resource "foo_resource" "b" {}
+resource "bar_resource" "c" {}
+resource "bar_resource" "ab" {
   provider = baz
 }
+resource "terraform_remote_state" "production" {}