configs: Error on invalid required_providers attrs

[alisdair]

A few users have recently been confused about the purpose of the required_providers objects, adding provider configuration parameters in addition to version and source. This previously did not cause an error so would result in a confusingly distant failure.

This commit adds a single diagnostic for any required_providers object which includes attributes other than version or source. Very open to suggestions on the diagnostic text!

Fixes #26160

Screenshot

[codecov]

Codecov Report

Merging #26184 into master will increase coverage by 0.10%.
The diff coverage is 75.97%.

Impacted Files	Coverage Δ
backend/local/backend_local.go	41.23% <ø> (ø)
internal/getproviders/types.go	37.90% <0.00%> (-0.94%)	⬇️
terraform/eval_provider.go	83.33% <50.00%> (-4.17%)	⬇️
internal/depsfile/locks.go	67.74% <67.74%> (ø)
internal/depsfile/locks_file.go	75.39% <75.39%> (ø)
terraform/node_data_refresh.go	87.14% <78.94%> (-7.69%)	⬇️
terraform/node_output.go	68.24% <79.66%> (+2.22%)	⬆️
configs/provider_requirements.go	81.05% <100.00%> (+2.48%)	⬆️
terraform/node_data_destroy.go	100.00% <100.00%> (ø)
terraform/node_resource_refresh.go	89.07% <100.00%> (+0.12%)	⬆️
... and 5 more

[pselle]

Question: would we refer to this as an "object" or is "block" more appropriate?

[alisdair]

Good question! I looked into what language we use elsewhere, and I think object is the right choice here.

required_providers is a block, but each of its attributes' values is either a string or an object. Another diagnostic uses this language in user-facing text:

terraform/configs/provider_requirements.go

Lines 132 to 137 in 898b459

	diags = append(diags, &hcl.Diagnostic{
	Severity: hcl.DiagError,
	Summary: "Invalid required_providers syntax",
	Detail: "required_providers entries must be strings or objects.",
	Subject: attr.Expr.Range().Ptr(),
	})

The documentation also refers to the value as an object:

Each argument in the required_providers block enables one provider. The key determines the provider's local name (its unique identifier within this module), and the value is an object with the following elements:

[mildwonkey]

Thanks for grabbing this so quickly! ❤️ 🎉

[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.