terraform: just hardcode a UUID in there for computed placeholders

terraform/resource_provider.go

@@ -1,9 +1,9 @@
 package terraform
 
-// ComputedPlaceholderKey is the configuration key given to Configure
-// in a ResourceProvider that contains the value for the computed value
-// placeholder when diffs are being done.
-const ComputedPlaceholderKey = "tf_computed_placeholder"
+// ComputedPlaceholder is the placeholder value for computed attributes.
+// ResourceProviders can compare values to this during a diff to determine
+// if it is just a placeholder.
+const ComputedPlaceholder = "74D93920-ED26-11E3-AC10-0800200C9A66"
 
 // ResourceProvider is an interface that must be implemented by any
 // resource provider: the thing that creates and manages the resources in
@@ -33,14 +33,6 @@ type ResourceProvider interface {
 		map[string]interface{}) (ResourceDiff, error)
 }
 
-// ResourceProviderCommonConfig contains the common configuration
-// keys that are sent with every resource provider configuration.
-// This can be used with something like mapstructure to extract
-// the proper value.
-type ResourceProviderCommonConfig struct {
-	TFComputedPlaceholder string `mapstructure:"tf_computed_placeholder"`
-}
-
 // ResourceType is a type of resource that a resource provider can manage.
 type ResourceType struct {
 	Name string

terraform/resource_provider_mock.go

@@ -1,9 +1,5 @@
 package terraform
 
-import (
-	"github.com/mitchellh/mapstructure"
-)
-
 // MockResourceProvider implements ResourceProvider but mocks out all the
 // calls for testing purposes.
 type MockResourceProvider struct {
@@ -11,7 +7,6 @@ type MockResourceProvider struct {
 	Meta interface{}
 
 	ConfigureCalled         bool
-	ConfigureCommonConfig   ResourceProviderCommonConfig
 	ConfigureConfig         map[string]interface{}
 	ConfigureReturnWarnings []string
 	ConfigureReturnError    error
@@ -28,11 +23,6 @@ type MockResourceProvider struct {
 func (p *MockResourceProvider) Configure(c map[string]interface{}) ([]string, error) {
 	p.ConfigureCalled = true
 	p.ConfigureConfig = c
-
-	if err := mapstructure.Decode(&p.ConfigureCommonConfig, c); err != nil {
-		return nil, err
-	}
-
 	return p.ConfigureReturnWarnings, p.ConfigureReturnError
 }
 

terraform/terraform.go

@@ -123,7 +123,9 @@ func (t *Terraform) diffWalkFn(
 
 		switch n.Meta.(type) {
 		case *config.ProviderConfig:
-			// Ignore, we don't treat this any differently.
+			// Ignore, we don't treat this any differently since we always
+			// initialize the provider on first use and use a lock to make
+			// sure we only do this once.
 			return nil
 		case *config.Resource:
 			// Continue