resource/aws_dynamodb_table: Allow disabling stream w/ empty view type

[radeksimko]

Fixes #1134

Despite stream_view_type being optional the validation is still being triggered which makes it impossible to parametrise the stream spec as described in #1134

Test results

=== RUN   TestAccAWSDynamoDbTable_streamSpecification
--- PASS: TestAccAWSDynamoDbTable_streamSpecification (92.66s)

[bflad]

Thank you for making the configuration more relevant to what we're trying to test here 👍

[bflad]

I understand where this is change coming from and the Terraform schema helpers don't necessarily make this easy, but it now allows this incorrect configuration to passthrough to the apply stage and fail:

stream_enabled   = true
stream_view_type = ""

e.g. testAccAWSDynamoDbConfigStreamSpecification(true, ""),

make testacc TEST=./aws TESTARGS='-run=TestAccAWSDynamoDbTable_streamSpecification'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws -v -run=TestAccAWSDynamoDbTable_streamSpecification -timeout 120m
=== RUN   TestAccAWSDynamoDbTable_streamSpecification
--- FAIL: TestAccAWSDynamoDbTable_streamSpecification (4.47s)
	testing.go:513: Step 0 error: Error applying: 1 error(s) occurred:

		* aws_dynamodb_table.basic-dynamodb-table: 1 error(s) occurred:

		* aws_dynamodb_table.basic-dynamodb-table: ValidationException: 1 validation error detected: Value '' at 'streamSpecification.streamViewType' failed to satisfy constraint: Member must satisfy enum value set: [OLD_IMAGE, KEYS_ONLY, NEW_AND_OLD_IMAGES, NEW_IMAGE]
			status code: 400, request id: BU4C7KSK4LOBT764E77I8FEOCRVV4KQNSO5AEMVJF66Q9ASUAAJG
FAIL
exit status 1
FAIL	github.com/terraform-providers/terraform-provider-aws/aws	4.517s
make: *** [testacc] Error 1

[radeksimko]

@bflad Added validation as discussed 😉

I also removed Computed from stream_enabled as it doesn't seem to be necessary there at all. I was tempted to do the same for stream_view_type and set Default instead, but we don't have any helper schemas to help us differentiate between defaults and undefined yet, so I left it as is.

All DynamoDB acceptance tests are still passing.

[bflad]

LGTM!

[bflad]

This has been released in terraform-provider-aws version 1.9.0. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!