Merge pull request #362 from hashicorp/f-dummy-provider

Add a "null" provider

builtin/bins/provider-null/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"github.com/hashicorp/terraform/builtin/providers/null"
+	"github.com/hashicorp/terraform/plugin"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func main() {
+	plugin.Serve(&plugin.ServeOpts{
+		ProviderFunc: func() terraform.ResourceProvider {
+			return null.Provider()
+		},
+	})
+}

builtin/bins/provider-null/main_test.go

@@ -0,0 +1 @@
+package main

builtin/providers/null/provider.go

@@ -0,0 +1,17 @@
+package null
+
+import (
+	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+// Provider returns a terraform.ResourceProvider.
+func Provider() terraform.ResourceProvider {
+	return &schema.Provider{
+		Schema: map[string]*schema.Schema{},
+
+		ResourcesMap: map[string]*schema.Resource{
+			"null_resource": resource(),
+		},
+	}
+}

builtin/providers/null/provider_test.go

@@ -0,0 +1,18 @@
+package null
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestProvider(t *testing.T) {
+	if err := Provider().(*schema.Provider).InternalValidate(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}
+
+func TestProvider_impl(t *testing.T) {
+	var _ terraform.ResourceProvider = Provider()
+}

builtin/providers/null/resource.go

@@ -0,0 +1,42 @@
+package null
+
+import (
+	"fmt"
+	"math/rand"
+	"time"
+
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func init() {
+	rand.Seed(time.Now().Unix())
+}
+
+func resource() *schema.Resource {
+	return &schema.Resource{
+		Create: resourceCreate,
+		Read:   resourceRead,
+		Update: resourceUpdate,
+		Delete: resourceDelete,
+
+		Schema: map[string]*schema.Schema{},
+	}
+}
+
+func resourceCreate(d *schema.ResourceData, meta interface{}) error {
+	d.SetId(fmt.Sprintf("%d", rand.Int()))
+	return nil
+}
+
+func resourceRead(d *schema.ResourceData, meta interface{}) error {
+	return nil
+}
+
+func resourceUpdate(d *schema.ResourceData, meta interface{}) error {
+	return nil
+}
+
+func resourceDelete(d *schema.ResourceData, meta interface{}) error {
+	d.SetId("")
+	return nil
+}

terraform/context.go

@@ -634,13 +634,12 @@ func (c *walkContext) applyWalkFn() depgraph.WalkFunc {
 				return err
 			}
 
-			// This should never happen because we check if Diff.Empty above.
-			// If this happened, then the diff above returned a bad diff.
+			// This can happen if we aren't actually applying anything
+			// except an ID (the "null" provider). It is not really an issue
+			// since the Same check later down will catch any real problems.
 			if diff == nil {
-				return fmt.Errorf(
-					"%s: diff became nil during Apply. This is a bug with "+
-						"the resource provider. Please report a bug.",
-					r.Id)
+				diff = new(InstanceDiff)
+				diff.init()
 			}
 
 			// Delete id from the diff because it is dependent on