Add validation for stack block names

TODO: Revist checking Stack concepts in the static validators

Other validators are more generic and can be applied to any block/attribute/etc, but this one is specific to the stack block types. I'm sure this could be done in a more generic way, but I'm not sure if it's worth it at the moment.

The names of these blocks are used as identifiers in the stack and are used in the UI, so they have to be valid Terraform identifiers or else the stack will not be able to be created. This is a very basic check to ensure that the names are valid until we can do more advanced checks or use the cloud api.

I tried adding this to the earlydecoder, but we do not seem to report the diagnostics there at all currently, so nothing was being reported. I'm not sure if that's a bug or intended.

internal/features/stacks/decoder/validations/valid_name.go

@@ -0,0 +1,71 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package validations
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/hcl-lang/schema"
+	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/hcl/v2/hclsyntax"
+)
+
+type StackBlockValidName struct{}
+
+func (sb StackBlockValidName) Visit(ctx context.Context, node hclsyntax.Node, nodeSchema schema.Schema) (context.Context, hcl.Diagnostics) {
+	var diags hcl.Diagnostics
+
+	block, ok := node.(*hclsyntax.Block)
+	if !ok {
+		return ctx, diags
+	}
+
+	if nodeSchema == nil {
+		return ctx, diags
+	}
+
+	// TODO: Revist checking Stack concepts in the static validators
+	// 	Other validators are more generic and can be applied to any block/attribute/etc, but
+	// 	this one is specific to the stack block types. I'm sure this could be done in a more generic way,
+	// 	but I'm not sure if it's worth it at the moment. The names of these blocks are used as identifiers
+	//  in the stack and are used in the UI, so they have to be valid Terraform identifiers or else the stack
+	//  will not be able to be created. This is a very basic check to ensure that the names are valid until we can
+	//  do more advanced checks or use the cloud api.
+	//  I tried adding this to the earlydecoder, but we do not seem to report the diagnostics there at all currently,
+	//  so nothing was being reported. I'm not sure if that's a bug or intended.
+
+	switch block.Type {
+	// stack
+	case "component":
+		diags = hasValidNameLabel(block, diags)
+	// case "provider":
+	// case "required_providers":
+	case "variable":
+		diags = hasValidNameLabel(block, diags)
+	case "output":
+		diags = hasValidNameLabel(block, diags)
+	// deployment
+	case "deployment":
+		diags = hasValidNameLabel(block, diags)
+	case "identity_token":
+		diags = hasValidNameLabel(block, diags)
+	case "orchestrate":
+		diags = hasValidNameLabel(block, diags)
+	}
+
+	return ctx, diags
+}
+
+func hasValidNameLabel(block *hclsyntax.Block, diags hcl.Diagnostics) hcl.Diagnostics {
+	if !hclsyntax.ValidIdentifier(block.Labels[0]) {
+		diags = append(diags, &hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  fmt.Sprintf("Invalid %q name %q", block.Type, block.Labels[0]),
+			Detail:   "Names must be valid identifiers: beginning with a letter or underscore, followed by zero or more letters, digits, or underscores.",
+			Subject:  block.LabelRanges[0].Ptr(),
+		})
+	}
+	return diags
+}

internal/features/stacks/decoder/validators.go

@@ -14,7 +14,8 @@ var stackValidators = []validator.Validator{
 	validator.DeprecatedBlock{},
 	validator.MaxBlocks{},
 	validator.MinBlocks{},
-	validations.MissingRequiredAttribute{},
 	validator.UnexpectedAttribute{},
 	validator.UnexpectedBlock{},
+	validations.MissingRequiredAttribute{},
+	validations.StackBlockValidName{},
 }