Refactor merging + add abstraction for attributes (#51)

* initial refactor

* added primitives + collection merge tests

* add collection nested attributes

* type

* add single nested test

* add main attributes tests and delete old merge functionality

* pointer test

* license headers

* rename package, structs, and test methods

* add data source impl

* add tests

* add provider implementation

* add implementations to oas and tests

* remove merge package

* add error returns + TODOs for future considerations

* update allocations + add error join return

Author: austinvalle

internal/mapper/attrmapper/attributes.go

@@ -0,0 +1,121 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package attrmapper
+
+import (
+	"errors"
+
+	"github.com/hashicorp/terraform-plugin-codegen-spec/datasource"
+	"github.com/hashicorp/terraform-plugin-codegen-spec/provider"
+	"github.com/hashicorp/terraform-plugin-codegen-spec/resource"
+)
+
+type ResourceAttribute interface {
+	GetName() string
+	Merge(ResourceAttribute) (ResourceAttribute, error)
+	ToSpec() resource.Attribute
+}
+
+type ResourceAttributes []ResourceAttribute
+
+func (targetSlice ResourceAttributes) Merge(mergeSlices ...ResourceAttributes) (ResourceAttributes, error) {
+	for _, mergeSlice := range mergeSlices {
+		for _, mergeAttribute := range mergeSlice {
+			// As we compare attributes, if we don't find a match, we should add this attribute to the slice after
+			isNewAttribute := true
+
+			for i, targetAttribute := range targetSlice {
+				if targetAttribute.GetName() == mergeAttribute.GetName() {
+					// TODO: determine how to surface this error
+					targetSlice[i], _ = targetAttribute.Merge(mergeAttribute)
+
+					isNewAttribute = false
+					break
+				}
+			}
+
+			if isNewAttribute {
+				// Add this back to the original slice to avoid adding duplicate attributes from different mergeSlices
+				targetSlice = append(targetSlice, mergeAttribute)
+			}
+		}
+	}
+
+	return targetSlice, nil
+}
+
+func (attributes ResourceAttributes) ToSpec() []resource.Attribute {
+	specAttributes := make([]resource.Attribute, 0, len(attributes))
+	for _, attribute := range attributes {
+		specAttributes = append(specAttributes, attribute.ToSpec())
+	}
+
+	return specAttributes
+}
+
+type DataSourceAttribute interface {
+	GetName() string
+	Merge(DataSourceAttribute) (DataSourceAttribute, error)
+	ToSpec() datasource.Attribute
+}
+
+type DataSourceAttributes []DataSourceAttribute
+
+func (targetSlice DataSourceAttributes) Merge(mergeSlices ...DataSourceAttributes) (DataSourceAttributes, error) {
+	var errResult error
+
+	for _, mergeSlice := range mergeSlices {
+		for _, mergeAttribute := range mergeSlice {
+			// As we compare attributes, if we don't find a match, we should add this attribute to the slice after
+			isNewAttribute := true
+
+			for i, targetAttribute := range targetSlice {
+				if targetAttribute.GetName() == mergeAttribute.GetName() {
+					mergedAttribute, err := targetAttribute.Merge(mergeAttribute)
+					if err != nil {
+						// TODO: consider how best to surface this error
+						// Currently, if the merge fails we should just keep the original target attribute for now
+						errResult = errors.Join(errResult, err)
+					} else {
+						targetSlice[i] = mergedAttribute
+					}
+
+					isNewAttribute = false
+					break
+				}
+			}
+
+			if isNewAttribute {
+				// Add this back to the original slice to avoid adding duplicate attributes from different mergeSlices
+				targetSlice = append(targetSlice, mergeAttribute)
+			}
+		}
+	}
+
+	return targetSlice, errResult
+}
+
+func (attributes DataSourceAttributes) ToSpec() []datasource.Attribute {
+	specAttributes := make([]datasource.Attribute, 0, len(attributes))
+	for _, attribute := range attributes {
+		specAttributes = append(specAttributes, attribute.ToSpec())
+	}
+
+	return specAttributes
+}
+
+type ProviderAttribute interface {
+	ToSpec() provider.Attribute
+}
+
+type ProviderAttributes []ProviderAttribute
+
+func (attributes ProviderAttributes) ToSpec() []provider.Attribute {
+	specAttributes := make([]provider.Attribute, 0, len(attributes))
+	for _, attribute := range attributes {
+		specAttributes = append(specAttributes, attribute.ToSpec())
+	}
+
+	return specAttributes
+}