terraform: provider input should be scoped by path

The provider input before wasn't scoped by path, which caused
non-descendant parts of the graph to grab the configuration of another
sub-tree. The result is that you'd often get copied provider
configurations across the module barriers.

See GH-2024

terraform/eval_context_builtin.go

@@ -168,14 +168,32 @@ func (ctx *BuiltinEvalContext) ProviderInput(n string) map[string]interface{} {
 	ctx.ProviderLock.Lock()
 	defer ctx.ProviderLock.Unlock()
 
-	return ctx.ProviderInputConfig[n]
+	// Make a copy of the path so we can safely edit it
+	path := ctx.Path()
+	pathCopy := make([]string, len(path)+1)
+	copy(pathCopy, path)
+
+	// Go up the tree.
+	for i := len(path) - 1; i >= 0; i-- {
+		pathCopy[i+1] = n
+		k := PathCacheKey(pathCopy[:i+2])
+		if v, ok := ctx.ProviderInputConfig[k]; ok {
+			return v
+		}
+	}
+
+	return nil
 }
 
 func (ctx *BuiltinEvalContext) SetProviderInput(n string, c map[string]interface{}) {
-	ctx.ProviderLock.Lock()
-	defer ctx.ProviderLock.Unlock()
+	providerPath := make([]string, len(ctx.Path())+1)
+	copy(providerPath, ctx.Path())
+	providerPath[len(providerPath)-1] = n
 
-	ctx.ProviderInputConfig[n] = c
+	// Save the configuration
+	ctx.ProviderLock.Lock()
+	ctx.ProviderInputConfig[PathCacheKey(providerPath)] = c
+	ctx.ProviderLock.Unlock()
 }
 
 func (ctx *BuiltinEvalContext) ParentProviderConfig(n string) *ResourceConfig {

terraform/eval_context_builtin_test.go

@@ -0,0 +1,42 @@
+package terraform
+
+import (
+	"reflect"
+	"sync"
+	"testing"
+)
+
+func TestBuiltinEvalContextProviderInput(t *testing.T) {
+	var lock sync.Mutex
+	cache := make(map[string]map[string]interface{})
+
+	ctx1 := testBuiltinEvalContext(t)
+	ctx1.PathValue = []string{"root"}
+	ctx1.ProviderInputConfig = cache
+	ctx1.ProviderLock = &lock
+
+	ctx2 := testBuiltinEvalContext(t)
+	ctx2.PathValue = []string{"root", "child"}
+	ctx2.ProviderInputConfig = cache
+	ctx2.ProviderLock = &lock
+
+	expected1 := map[string]interface{}{"value": "foo"}
+	ctx1.SetProviderInput("foo", expected1)
+
+	expected2 := map[string]interface{}{"value": "bar"}
+	ctx2.SetProviderInput("foo", expected2)
+
+	actual1 := ctx1.ProviderInput("foo")
+	actual2 := ctx2.ProviderInput("foo")
+
+	if !reflect.DeepEqual(actual1, expected1) {
+		t.Fatalf("bad: %#v %#v", actual1, expected1)
+	}
+	if !reflect.DeepEqual(actual2, expected2) {
+		t.Fatalf("bad: %#v %#v", actual2, expected2)
+	}
+}
+
+func testBuiltinEvalContext(t *testing.T) *BuiltinEvalContext {
+	return &BuiltinEvalContext{}
+}