Merge pull request #13665 from hashicorp/jbardin/context-return-state

context Refresh and Apply sometimes return nil

backend/local/backend_apply.go

@@ -102,7 +102,9 @@ func (b *Local) opApply(
 	doneCh := make(chan struct{})
 	go func() {
 		defer close(doneCh)
-		applyState, applyErr = tfCtx.Apply()
+		_, applyErr = tfCtx.Apply()
+		// we always want the state, even if apply failed
+		applyState = tfCtx.State()
 
 		/*
 			// Record any shadow errors for later

terraform/context.go

@@ -453,8 +453,17 @@ func (c *Context) Input(mode InputMode) error {
 // Apply applies the changes represented by this context and returns
 // the resulting state.
 //
-// In addition to returning the resulting state, this context is updated
+// Even in the case an error is returned, the state may be returned and will
-// with the latest state.
+// potentially be partially updated.  In addition to returning the resulting
+// state, this context is updated with the latest state.
+//
+// If the state is required after an error, the caller should call
+// Context.State, rather than rely on the return value.
+//
+// TODO: Apply and Refresh should either always return a state, or rely on the
+//       State() method. Currently the helper/resource testing framework relies
+//       on the absence of a returned state to determine if Destroy can be
+//       called, so that will need to be refactored before this can be changed.
 func (c *Context) Apply() (*State, error) {
 	defer c.acquireRun("apply")()
 
@@ -580,7 +589,7 @@ func (c *Context) Plan() (*Plan, error) {
 // to their latest state. This will update the state that this context
 // works with, along with returning it.
 //
-// Even in the case an error is returned, the state will be returned and
+// Even in the case an error is returned, the state may be returned and
 // will potentially be partially updated.
 func (c *Context) Refresh() (*State, error) {
 	defer c.acquireRun("refresh")()

terraform/state.go

@@ -1960,12 +1960,12 @@ func ReadStateV2(jsonBytes []byte) (*State, error) {
 		}
 	}
 
-	// Sort it
-	state.sort()
-
 	// catch any unitialized fields in the state
 	state.init()
 
+	// Sort it
+	state.sort()
+
 	return state, nil
 }
 
@@ -1995,12 +1995,12 @@ func ReadStateV3(jsonBytes []byte) (*State, error) {
 		}
 	}
 
-	// Sort it
-	state.sort()
-
 	// catch any unitialized fields in the state
 	state.init()
 
+	// Sort it
+	state.sort()
+
 	// Now we write the state back out to detect any changes in normaliztion.
 	// If our state is now written out differently, bump the serial number to
 	// prevent conflicts.
@@ -2020,12 +2020,17 @@ func ReadStateV3(jsonBytes []byte) (*State, error) {
 
 // WriteState writes a state somewhere in a binary format.
 func WriteState(d *State, dst io.Writer) error {
-	// Make sure it is sorted
+	// writing a nil state is a noop.
-	d.sort()
+	if d == nil {
+		return nil
+	}
 
 	// make sure we have no uninitialized fields
 	d.init()
 
+	// Make sure it is sorted
+	d.sort()
+
 	// Ensure the version is set
 	d.Version = StateVersion