nil TypeMap permadiff

[appilon]

Module version

0.4.2

Relevant provider source code

"permissions": {
				Type:        types.MapType{ElemType: types.BoolType},
				Optional:    true,
			},

Terraform Configuration Files

resource "sample_profile" "test" {
  name            = "test"
  description     = "test update"
  # permissions = {}
}

Expected Behavior

After applying the initial config, I expect a subsequent plan to be noop.

Actual Behavior

Terraform seems to think the current state has an empty set (but not nil) which causes a diff with the plan (nil).

- permissions     = {} -> null

Steps to Reproduce

References

[appilon]

I attempted to massage the plan to match

type fixEmptyMap struct {
	emptyDescriptions
}

func (fixEmptyMap) Modify(_ context.Context, req tfsdk.ModifyAttributePlanRequest, resp *tfsdk.ModifyAttributePlanResponse) {
	if req.AttributeState == nil {
		return
	}
	state := req.AttributeState.(types.Map)
	plan := req.AttributePlan.(types.Map)
	if len(state.Elems) == 0 && !state.Null && plan.Null {
		plan.Null = false
		plan.Elems = make(map[string]attr.Value, 0)
		resp.AttributePlan = plan
	}
}

But got the following error on plan

╷
│ Error: Provider produced invalid plan
│
│ Provider "registry.terraform.io/hashicorp/salesforce" planned an invalid value for salesforce_profile.test.permissions: planned value cty.MapValEmpty(cty.Bool) for a non-computed attribute.
│
│ This is a bug in the provider, which should be reported in the provider's own issue tracker.
╵

[bflad]

Would you be able to show how the attribute is being set into state (if it is) during Create and/or Read?

[appilon]

The permissions go through a bit of an expansion from the API response but the logic is the following:

        // expand permissions
	permissions := make(map[string]attr.Value, len(includePermissions))
	for _, k := range includePermissions {
		v, ok := p[k]
		trimmedKey := strings.TrimPrefix(k, "Permissions")
		if ok {
			permissions[trimmedKey] = types.Bool{Value: v.(bool)}
		} else {
			// set to unknown, maybe we should panic?
			permissions[trimmedKey] = types.Bool{Unknown: true}
		}
	}
	if len(permissions) > 0 {
		data.Permissions = types.Map{ElemType: types.BoolType, Elems: permissions}
	}

I am certain len(includePermissions) == 0 therefore, data.Permissions should just be the zero value of that type. I can confirm

State setting code is very simple within Read

	d := pMap.ToStateData(data.PermissionKeys("Permissions")...)
	// copy the ID back over
	d.Id = data.Id

	resp.Diagnostics = resp.State.Set(ctx, &d)

[appilon]

Confirmed, Permissions is whatever the zero value is

data := profileResourceData{
		Name:          p["Name"].(string),
		UserLicenseId: p["UserLicenseId"].(string),
		// Permissions is not touched
	}

[bflad]

This may be similar to #201. Does explicitly setting the value Null: true help? e.g. something like:

if len(permissions) > 0 {
	data.Permissions = types.Map{ElemType: types.BoolType, Elems: permissions}
} else {
	data.Permissions = types.Map{ElemType: types.BoolType, Null: true}
}

Since types.Map uses Null bool under the hood, its zero-value would be false. This may however cause a different issue where if the configuration is permissions = {} that may now permadiff.

It might be possible to first manually passthrough the Config value (e.g. retrieved via GetAttribute) into Permissions then overwrite it after that length check.

[bflad]

It may also be possible to use Permissions map[string]bool or something similar in the data type to workaround this.

[bflad]

Hey again @appilon 👋 Did you find a resolution for this situation or does either of the above help?

[appilon]

@bflad I will prioritize revisiting this this week.

[project0]

I encountered exactly the same problem today.
The backend always provides a empty Map when no entries are set, no nil pointer. Now i have two options, either return the empty map, or when no entries are set set to Null:true. Both will always conflict with one of the scenarios in the terraform config.

// assuming someone generates a empty map
Label={}
// or not set at all
Label=null

Technically i dont care, both will always be empty for me as it is not computed.
Not sure how to handle this, maybe something like a custom plan may help like "NullAreEmpty"

[bflad]

We're discussing a potential path forward here over in #447 with potentially modifying the zero-values of the types value types to be null, so I'm going to close this issue out so focus efforts and discussion in one place.

@project0 if you didn't try it already, I think you may be able to do something like you propose by setting the map attribute as Computed: true and introducing the mentioned attribute plan modifier that converts a null configuration value to an empty map plan value.

[github-actions]

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 have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.