config: mark even index accesses as a multi-access

config/config.go

@@ -4,6 +4,7 @@ package config
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 
 	"github.com/hashicorp/terraform/helper/multierror"
@@ -222,10 +223,24 @@ func NewResourceVariable(key string) (*ResourceVariable, error) {
 	parts := strings.SplitN(key, ".", 3)
 	field := parts[2]
 	multi := false
+	var index int
+
+	if idx := strings.Index(field, "."); idx != -1 {
+		indexStr := field[:idx]
+		multi = indexStr == "*"
+		index = -1
+
+		if !multi {
+			indexInt, err := strconv.ParseInt(indexStr, 0, 0)
+			if err == nil {
+				multi = true
+				index = int(indexInt)
+			}
+		}
 
-	if idx := strings.Index(field, "."); idx != -1 && field[:idx] == "*" {
-		multi = true
-		field = field[idx+1:]
+		if multi {
+			field = field[idx+1:]
+		}
 	}
 
 	return &ResourceVariable{
@@ -233,6 +248,7 @@ func NewResourceVariable(key string) (*ResourceVariable, error) {
 		Name:  parts[1],
 		Field: field,
 		Multi: multi,
+		Index: index,
 		key:   key,
 	}, nil
 }

config/config_test.go

@@ -94,6 +94,34 @@ func TestResourceVariable_Multi(t *testing.T) {
 	}
 }
 
+func TestResourceVariable_MultiIndex(t *testing.T) {
+	cases := []struct {
+		Input string
+		Index int
+		Field string
+	}{
+		{"foo.bar.*.baz", -1, "baz"},
+		{"foo.bar.0.baz", 0, "baz"},
+		{"foo.bar.5.baz", 5, "baz"},
+	}
+
+	for _, tc := range cases {
+		v, err := NewResourceVariable(tc.Input)
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+		if !v.Multi {
+			t.Fatalf("should be multi: %s", tc.Input)
+		}
+		if v.Index != tc.Index {
+			t.Fatalf("bad: %d\n\n%s", v.Index, tc.Input)
+		}
+		if v.Field != tc.Field {
+			t.Fatalf("bad: %s\n\n%s", v.Field, tc.Input)
+		}
+	}
+}
+
 func TestNewUserVariable(t *testing.T) {
 	v, err := NewUserVariable("var.bar")
 	if err != nil {