fix(transform): Pass prev dataset to ExecScript

Pass prev dataset as well as next dataset, in order to support new get_body functionality added by qri-io/startf#41.

actions/dataset.go

@@ -46,7 +46,7 @@ func SaveDataset(node *p2p.QriNode, changes *dataset.Dataset, secrets map[string
 		mutateCheck := mutatedComponentsFunc(changes)
 
 		changes.Transform.Secrets = secrets
-		if err = ExecTransform(node, changes, scriptOut, mutateCheck); err != nil {
+		if err = ExecTransform(node, changes, prev, scriptOut, mutateCheck); err != nil {
 			return
 		}
 		// changes.Transform.SetScriptFile(mutable.Transform.ScriptFile())

actions/transform.go

@@ -39,7 +39,7 @@ please adjust either the transform script or remove the supplied '%s'`, path[0],
 }
 
 // ExecTransform executes a designated transformation
-func ExecTransform(node *p2p.QriNode, ds *dataset.Dataset, scriptOut io.Writer, mutateCheck func(...string) error) error {
+func ExecTransform(node *p2p.QriNode, ds, prev *dataset.Dataset, scriptOut io.Writer, mutateCheck func(...string) error) error {
 	if ds.Transform == nil {
 		return fmt.Errorf("no transform provided")
 	}
@@ -64,7 +64,7 @@ func ExecTransform(node *p2p.QriNode, ds *dataset.Dataset, scriptOut io.Writer,
 		setSecrets,
 	}
 
-	if err := startf.ExecScript(ds, configs...); err != nil {
+	if err := startf.ExecScript(ds, prev, configs...); err != nil {
 		return err
 	}
 

actions/transform_test.go

@@ -27,11 +27,13 @@ func TestExecTransform(t *testing.T) {
 		t.Fatal(err.Error())
 	}
 
-	ds := &dataset.Dataset{
+	prev := &dataset.Dataset{
 		Structure: &dataset.Structure{
 			Format: "json",
 			Schema: dataset.BaseSchemaArray,
 		},
+	}
+	next := &dataset.Dataset{
 		Transform: &dataset.Transform{
 			Syntax:  "starlark",
 			Config:  map[string]interface{}{"foo": "config"},
@@ -45,9 +47,9 @@ def transform(ds,ctx):
 	ctx.get_secret("bar")
 	ds.set_body([1,2,3])
 	`)
-	ds.Transform.SetScriptFile(qfs.NewMemfileBytes("transform.star", data))
+	next.Transform.SetScriptFile(qfs.NewMemfileBytes("transform.star", data))
 
-	if err := ExecTransform(node, ds, nil, nil); err != nil {
+	if err := ExecTransform(node, next, prev, nil, nil); err != nil {
 		t.Error(err.Error())
 	}
 }

cmd/cmd_test.go

@@ -657,6 +657,44 @@ func TestSaveTransformWithoutChanges(t *testing.T) {
 	}
 }
 
+// Test that calling `get_body` will retrieve the body of the previous version.
+func TestTransformUsingGetBodyAndSetBody(t *testing.T) {
+	if err := confirmQriNotRunning(); err != nil {
+		t.Skip(err.Error())
+	}
+
+	// To keep hashes consistent, artificially specify the timestamp by overriding
+	// the dsfs.Timestamp func
+	prev := dsfs.Timestamp
+	defer func() { dsfs.Timestamp = prev }()
+	dsfs.Timestamp = func() time.Time { return time.Date(2001, 01, 01, 01, 01, 01, 01, time.UTC) }
+
+	r := NewTestRepoRoot(t, "qri_test_save_transform_get_body")
+	defer r.Delete()
+
+	cmdR := r.CreateCommandRunner()
+	_, err := executeCommand(cmdR, "qri save --body=testdata/movies/body_two.json me/test_ds")
+	if err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	cmdR = r.CreateCommandRunner()
+	_, err = executeCommand(cmdR, "qri save --file=testdata/movies/tf_add_one.star me/test_ds")
+	if err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	// Read body from the dataset that was created with the transform
+	dsPath := r.GetPathForDataset(0)
+	actualBody := r.ReadBodyFromIPFS(dsPath + "/body.json")
+
+	// This body is body_two.json, with the numbers in the second column increased by 1.
+	expectBody := `[["Avatar",179],["Pirates of the Caribbean: At World's End",170]]`
+	if actualBody != expectBody {
+		t.Errorf("error, dataset actual:\n%s\nexpect:\n%s\n", actualBody, expectBody)
+	}
+}
+
 // TODO: Perhaps this utility should move to a lower package, and be used as a way to validate the
 // bodies of dataset in more of our test case. That would require extracting some parts out, like
 // pathFactory, which would probably necessitate the pathFactory taking the testRepoRoot as a

cmd/testdata/movies/body_two.json

@@ -0,0 +1,4 @@
+[
+    ["Avatar", 178],
+    ["Pirates of the Caribbean: At World's End", 169]
+]

cmd/testdata/movies/tf_add_one.star

@@ -0,0 +1,6 @@
+def transform(ds, ctx):
+  body = ds.get_body()
+  for row in body:
+    row[1] = row[1] + 1
+  ds.set_body(body)
+

lib/config.go

@@ -13,7 +13,6 @@ type ConfigMethods struct {
 	inst *Instance
 }
 
-
 // NewConfigMethods creates a configuration handle from an instance
 func NewConfigMethods(inst *Instance) *ConfigMethods {
 	return &ConfigMethods{inst: inst}