ResourceData.Set() doesn't set empty List/Set of String when Create/Update resource #766

jeremmfr · 2021-05-31T08:04:26Z

SDK version

github.com/hashicorp/terraform-plugin-sdk/v2 v2.6.1

Relevant provider source code

provider.go

package example

import (
	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
)

func Provider() *schema.Provider {
	return &schema.Provider{
		Schema: map[string]*schema.Schema{},
		ResourcesMap: map[string]*schema.Resource{
			"example_list": resourceList(),
		},
	}
}

resource_list.go

package example

import (
	"context"
	"log"

	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
)

func resourceList() *schema.Resource {
	return &schema.Resource{
		CreateContext: resourceListCreate,
		ReadContext:   resourceListRead,
		UpdateContext: resourceListUpdate,
		DeleteContext: resourceListDelete,
		Schema: map[string]*schema.Schema{
			"name": {
				Type:     schema.TypeString,
				Required: true,
			},
			"list": {
				Type:     schema.TypeList,
				Optional: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
			"set": {
				Type:     schema.TypeSet,
				Optional: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
			"list2": {
				Type:     schema.TypeList,
				Optional: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
			"set2": {
				Type:     schema.TypeSet,
				Optional: true,
				Elem:     &schema.Schema{Type: schema.TypeString},
			},
		},
	}
}

func resourceListCreate(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
	log.Printf("Create")
	d.SetId(d.Get("name").(string))

	return resourceListRead(ctx, d, m)
}

func resourceListRead(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
	log.Printf("Read")
	v := make([]string, 0)
	if err := d.Set("list", v); err != nil {
		panic(err)
	}
	if err := d.Set("set", v); err != nil {
		panic(err)
	}

	return nil
}

func resourceListUpdate(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
	log.Printf("Update")
	v := make([]string, 0)
	if err := d.Set("list2", v); err != nil {
		panic(err)
	}
	if err := d.Set("set2", v); err != nil {
		panic(err)
	}

	return resourceListRead(ctx, d, m)
}

func resourceListDelete(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
	log.Printf("Delete")

	return nil
}

Terraform Configuration Files

terraform {
  required_providers {
    example = {
      source = "sdk/example"
    }
  }
}

resource "example_list" "list" {
  name = "test"
}

Debug Output

First apply: https://gist.github.com/jeremmfr/8fdf0aef9a9dba35aa7c2a429013a466
Second apply: https://gist.github.com/jeremmfr/ce7fc52349967f60dbb11845b5839e7a

Especially in second apply :

Terraform detected the following changes made outside of Terraform since the last "terraform apply":

  # example_list.list has been changed
  ~ resource "example_list" "list" {
        id   = "test2"
      + list = []
        name = "test2"
      + set  = []
    }

Expected Behavior

list and set arguments set in state to an empty list on first apply (create).

Actual Behavior

list and set arguments set in state to an empty list only when refresh resource.
With new Terraform version (0.15.4), the note Note: Objects have changed outside of Terraform appears for the wrong reason.

Steps to Reproduce

terraform init
terraform apply -auto-approve
terraform apply -auto-approve

Others errors

If I update name argument, list2 and set2 not set to an empty list in state when apply (update)

The text was updated successfully, but these errors were encountered:

marcinwyszynski · 2021-06-02T20:37:24Z

In case that's helpful here's some further notes from my own investigation as the users of a provider I maintain noticed this spam:

setting the field to an empty list or set results in the state representation of that field being set to null;
this was only the case with collections (I tested lists and sets) of strings (presumably all primitives, but I haven't checked?) but not complex types (struct pointers?) - empty lists of those are properly represented as [];
running terraform apply -refresh-only reliably fixes the problem and changes the state representation to [];

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766 (cherry picked from commit a2dafcf)

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766 (cherry picked from commit a2dafcf)

jeremmfr added the bug Something isn't working label May 31, 2021

jeremmfr added a commit to jeremmfr/terraform-plugin-sdk that referenced this issue Jun 18, 2021

fix normalizeNullValues when apply resource to accept an empty list

16ccf25

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766

jeremmfr added a commit to jeremmfr/terraform-plugin-sdk that referenced this issue Jun 18, 2021

fix normalizeNullValues when apply resource to accept an empty list

a2dafcf

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766

jeremmfr linked a pull request Jun 18, 2021 that will close this issue

Fixes #766: fix normalizeNullValues when apply resource to accept an empty list #772

Open

jeremmfr added a commit to jeremmfr/terraform-plugin-sdk that referenced this issue Dec 16, 2021

fix normalizeNullValues when apply resource to accept an empty list

c3b7a06

and doesn't use a null src otherwise a drift is generate when refresh resource Fixes hashicorp#766

shinny-taojiachun mentioned this issue Nov 2, 2023

Workaround for nullVal and emptyVal in plugin-sdk shinnytech/terraform-provider-tencentcloud#4

Merged

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ResourceData.Set() doesn't set empty List/Set of String when Create/Update resource #766

ResourceData.Set() doesn't set empty List/Set of String when Create/Update resource #766

jeremmfr commented May 31, 2021 •

edited

marcinwyszynski commented Jun 2, 2021 •

edited

ResourceData.Set() doesn't set empty List/Set of String when Create/Update resource #766

ResourceData.Set() doesn't set empty List/Set of String when Create/Update resource #766

Comments

jeremmfr commented May 31, 2021 • edited

SDK version

Relevant provider source code

provider.go

resource_list.go

Terraform Configuration Files

Debug Output

Expected Behavior

Actual Behavior

Steps to Reproduce

Others errors

marcinwyszynski commented Jun 2, 2021 • edited

jeremmfr commented May 31, 2021 •

edited

marcinwyszynski commented Jun 2, 2021 •

edited