Custom delete for dbforpostgresql:Configuration to reset to the correct default

[thomas11]

Resolves #3476.

The dbforpostgresql:Configuration resource cannot actually be deleted, so we reset it to its default value instead. However, there are many configuration parameters with different defaults. On delete, we first GET this configuration to read the correct default value, then set it. This is the same approach that az takes in az postgres flexible-server parameter set.

[github-actions]

Does the PR have any schema changes?

Looking good! No breaking changes found.
No new resources/functions.

[codecov]

Codecov Report

Attention: Patch coverage is 40.90909% with 39 lines in your changes missing coverage. Please review.

Project coverage is 56.80%. Comparing base (a8e5e1c) to head (ba9989d).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...esources/customresources/custom_postgres_config.go	29.16%	32 Missing and 2 partials ⚠️
...r/pkg/resources/customresources/customresources.go	66.66%	3 Missing and 1 partial ⚠️
provider/pkg/provider/provider.go	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3752      +/-   ##
==========================================
- Coverage   56.90%   56.80%   -0.10%     
==========================================
  Files          76       77       +1     
  Lines       11885    11947      +62     
==========================================
+ Hits         6763     6787      +24     
- Misses       4630     4665      +35     
- Partials      492      495       +3     

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[danielrbradley]

These look fine because these resources don't actually exist in the SDK. This is because these are listed in the v2-removed-resources.json file

https://github.com/pulumi/pulumi-azure-native/blob/0d0261fd754ec20a98c1b6336897d6935bd0cceb/versions/v2-removed-resources.json#L2660-L2661

[danielrbradley]

Yup, this looks fine with the new singleton handling 👍

[danielrbradley]

This might be a nice place to explain what a singleton is

Suggested change

	func isSingleton(resource *resourceVariant) bool {
	return resource.PathItem.Delete == nil || customresources.IsSingleton(resource.Path)
	}
	// isSingleton indicates if the resource is created and therefore deleted as
	// part of its parent resource. When deleting a singleton we will reset its
	// properties back to a default state. However a custom resource might still
	// provide a delete method to perform a custom reset.
	func isSingleton(resource *resourceVariant) bool {
	return resource.PathItem.Delete == nil || customresources.IsSingleton(resource.Path)
	}

[danielrbradley]

Ugh .. I find this magic global state for featureLookup lookup somewhat confusing. I think it was added for easier access at runtime in the provider .. but I guess this is fine to call to call during codegen too.

[pulumi-bot]

This PR has been shipped in release v2.76.0.