Update the Getting Started guide

README.md

@@ -122,7 +122,7 @@ resource "aws_s3_bucket" "example" {
 }
 ```
 
-Apply it and create the `aws_s3_bucket` resource with the AWS provider v3.74.3, which is the last version without deprecated warnings:
+Apply it and create the `aws_s3_bucket` resource with the AWS provider v3.74.3, which is the last version without deprecation warnings:
 
 ```
 # terraform -v
@@ -132,9 +132,10 @@ on linux_amd64
 
 # terraform apply -auto-approve
 # terraform state list
+aws_s3_bucket.example
 ```
 
-Then, let's upgrade the AWS provider to the latest v3.x, which allows you to refactor the `aws_s3_bucket` resource before upgrading v4:
+Then, let's upgrade the AWS provider to the latest v3.x, which allows you to refactor the `aws_s3_bucket` resource before upgrading v4. To update the provider version constraint, of course you can edit the `required_providers` block in the `config.tf` with your text editor, but it's easy to do with [tfupdate](https://github.com/minamijoyo/tfupdate):
 
 ```
 # tfupdate provider aws -v "~> 3.75" .
@@ -147,7 +148,23 @@ on linux_amd64
 + provider registry.terraform.io/hashicorp/aws v3.75.1
 ```
 
-Now it's time to upgrade Terraform configuration to the AWS provider v4 compatible with `tfedit`:
+You can see a deprecation warning as follows:
+
+```
+# terraform validate
+╷
+│ Warning: Argument is deprecated
+│
+│   with aws_s3_bucket.example,
+│   on main.tf line 3, in resource "aws_s3_bucket" "example":
+│    3:   acl    = "private"
+│
+│ Use the aws_s3_bucket_acl resource instead
+╵
+Success! The configuration is valid, but there were some validation warnings as shown above.
+```
+
+Now, it's time to upgrade Terraform configuration to the AWS provider v4 compatible with `tfedit`:
 
 ```
 # tfedit filter awsv4upgrade -u -f main.tf
@@ -167,6 +184,13 @@ resource "aws_s3_bucket_acl" "example" {
 }
 ```
 
+You can also see that the deprecation warning has been resolved:
+
+```
+# terraform validate
+Success! The configuration is valid.
+```
+
 At this point, if you run the `terraform plan` command, you can see that a new `aws_s3_bucket_acl` resource will be created:
 
 ```
@@ -175,7 +199,7 @@ At this point, if you run the `terraform plan` command, you can see that a new `
 Plan: 1 to add, 0 to change, 0 to destroy.
 ```
 
-Now it's time for tfmigrate, which allows you to run the `terraform import` command in a declarative way. Currently, generating a migration file feature has not been implemented yet, so create a migration file manually.
+To resolve the conflict between the configuration and the existing state, you need to import the new resource. As you know, you can run the `terraform import` command directly, but if you prefer to check the upgrade results without updating remote state, use [tfmigrate](https://github.com/minamijoyo/tfmigrate), which allows you to run the `terraform import` command in a declarative way. Currently, generating a migration file feature has not been implemented yet, so you need to create a migration file manually.
 
 ```
 # cat << EOF > tfmigrate_test.hcl
@@ -187,7 +211,7 @@ migration "state" "test" {
 EOF
 ```
 
-Run `tfmigrate plan` to check to see if `terraform plan` has no changes after the migration without updating remote tfstate:
+Run the `tfmigrate plan` command to check to see if the `terraform plan` command has no changes after the migration without updating remote state:
 
 ```
 # tfmigrate plan tfmigrate_test.hcl
@@ -208,9 +232,9 @@ YYYY/MM/DD hh:mm:ss [INFO] [migrator] state migrator apply success!
 ```
 
 The apply command computes a new state and pushes it to remote state.
-It will fail if terraform plan detects any diffs with the new state.
+It will fail if the `terraform plan` command detects any diffs with the new state.
 
-You can confirm the latest remote state has no changes with terraform plan:
+You can confirm the latest remote state has no changes with the `terraform plan` command:
 
 ```
 # terraform plan
@@ -222,6 +246,47 @@ aws_s3_bucket.example
 aws_s3_bucket_acl.example
 ```
 
+Finally, let's upgrade the AWS provider to the latest v4.x:
+
+```
+# tfupdate provider aws -v "~> 4.0" .
+# terraform init -upgrade
+# terraform -v
+Terraform v1.1.7
+on linux_amd64
++ provider registry.terraform.io/hashicorp/aws v4.8.0
+
+# terraform validate
+╷
+│ Warning: Argument is deprecated
+│
+│   with provider["registry.terraform.io/hashicorp/aws"],
+│   on config.tf line 36, in provider "aws":
+│   36:   s3_force_path_style         = true
+│
+│ Use s3_use_path_style instead.
+```
+
+You will get the `s3_force_path_style` warning, but this is an issue caused by the sandbox environment using `localstack`, so it's ok to ignore it. (To resolve the warning, use `s3_use_path_style` instead, but note that this option is not available in v3.)
+
+You can confirm that the result of the `terraform plan` command is no changes in v4:
+
+```
+# terraform plan
+(snip.)
+No changes. Infrastructure is up-to-date.
+```
+
+To clean up the sandbox environment:
+
+```
+# terraform destroy -auto-approve
+# cd ../../
+# rm -rf tmp/dir1
+# exit
+$ docker-compose down
+```
+
 ## Install
 
 ### Source

test-fixtures/awsv4upgrade/aws_s3_bucket/simple/config.tf

@@ -5,7 +5,7 @@ terraform {
     bucket = "tfstate-test"
     key    = "test/terraform.tfstate"
 
-    // mock s3 endpoint with localstack
+    # mock s3 endpoint with localstack
     endpoint                    = "http://localstack:4566"
     access_key                  = "dummy"
     secret_key                  = "dummy"
@@ -23,7 +23,7 @@ terraform {
 }
 
 # https://www.terraform.io/docs/providers/aws/index.html
-# https://www.terraform.io/docs/providers/aws/guides/custom-service-endpoints.html#localstack
+# https://registry.terraform.io/providers/hashicorp/aws/latest/docs/guides/custom-service-endpoints#localstack
 provider "aws" {
   region = "ap-northeast-1"
 
@@ -34,8 +34,9 @@ provider "aws" {
   skip_region_validation      = true
   skip_requesting_account_id  = true
   s3_force_path_style         = true
+  # s3_use_path_style         = true
 
-  // mock endpoints with localstack
+  # mock endpoints with localstack
   endpoints {
     s3 = "http://localstack:4566"
   }