Deprecate (helper/schema.ResourceData).Partial and (helper/schema.ResourceData).SetPartial

[bflad]

SDK version

v1.6.0

Relevant provider source code

func exampleThingUpdate(d *schema.ResourceData, meta interface{}) error {
	// ...

	d.Partial(true)

	if d.HasChange("widget") {
		// ... update widget
		d.SetPartial("widget")
	}

	d.Partial(false)

	// ...
}

Expected Behavior

That coding d.Partial() and d.SetPartial() into the update logic is beneficial.

Actual Behavior

Their usage is only beneficial in very small edge cases, e.g. when those attributes are not refreshed on the next run after an error occurs (Terraform is called with -refresh=false). As another side effect, only the configuration value is passed through into the state, not the potentially different API result after re-read, which could be incorrect.

Most resources should already be coded to perform a full refresh of all possible attribute values for drift detection, so partial state updates would (and should 😄 ) be overwritten on the next Terraform run.

Steps to Reproduce

1. terraform apply (with error)
2. terraform apply -refresh=false (not recommended)

References

• New Check: Discourage Usage of ResourceData.Partial() / ResourceData.SetPartial() bflad/tfproviderlint#91

[paultyng]

I added the 2.0.0 milestone to this as I think we can deprecate in 1.x and then remove in the 2.x line.

[ewbankkit]

The Writing Custom Providers chapter of Extending Terraform -
https://www.terraform.io/docs/extend/writing-custom-providers.html#error-handling-amp-partial-state - should be updated to remove references to partial mode.

[paultyng]

Thanks @ewbankkit, I opened an issue over on the website to do so.

[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 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.