dataworkaround: add workaround for datafactory 27816 (#4668)

* add workaround for datafactory 27816

* add explanatory comment for workaround

tools/importer-rest-api-specs/internal/components/apidefinitions/parser/dataworkarounds/workaround_datafactory_27816.go

@@ -0,0 +1,51 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package dataworkarounds
+
+import (
+	"fmt"
+	sdkModels "github.com/hashicorp/pandora/tools/data-api-sdk/v1/models"
+)
+
+var _ workaround = workaroundDataFactory27816{}
+
+// workaroundDataFactory27816 converts the `headers` property from a string to an interface - this can be removed once
+// https://github.com/Azure/azure-rest-api-specs/issues/27816 has been fixed
+type workaroundDataFactory27816 struct {
+}
+
+func (workaroundDataFactory27816) IsApplicable(serviceName string, apiVersion sdkModels.APIVersion) bool {
+	return serviceName == "DataFactory" && apiVersion.APIVersion == "2018-06-01"
+}
+
+func (workaroundDataFactory27816) Name() string {
+	return "DataFactory / 27816"
+}
+
+func (workaroundDataFactory27816) Process(input sdkModels.APIVersion) (*sdkModels.APIVersion, error) {
+	resource, ok := input.Resources["Pipelines"]
+	if !ok {
+		return nil, fmt.Errorf("expected a Resource named `Pipelines` but didn't get one")
+	}
+
+	model, ok := resource.Models["WebActivityTypeProperties"]
+	if !ok {
+		return nil, fmt.Errorf("couldn't find Model `WebActivityTypeProperties`")
+	}
+
+	field, ok := model.Fields["Headers"]
+	if !ok {
+		return nil, fmt.Errorf("couldn't find Field `Headers`")
+	}
+
+	if field.ObjectDefinition.NestedItem != nil {
+		field.ObjectDefinition.NestedItem.Type = sdkModels.RawObjectSDKObjectDefinitionType
+	}
+
+	model.Fields["Headers"] = field
+	resource.Models["WebActivityTypeProperties"] = model
+	input.Resources["Pipelines"] = resource
+
+	return &input, nil
+}

tools/importer-rest-api-specs/internal/components/apidefinitions/parser/dataworkarounds/workarounds.go

@@ -14,6 +14,7 @@ var workarounds = []workaround{
 	workaroundContainerRegistry32154{},
 	workaroundContainerService21394{},
 	workaroundDataFactory23013{},
+	workaroundDataFactory27816{},
 	workaroundDataMigration31001{},
 	workaroundDigitalTwins25120{},
 	workaroundHDInsight26838{},