Improve error message and add test for #1440 (#8268)

* Improve error message and add test for #1440

* lint

* lint

* Use %w instead of errors.Wrap

sdk/go/common/encoding/marshal.go

@@ -16,6 +16,7 @@ package encoding
 
 import (
 	"encoding/json"
+	"fmt"
 	"path/filepath"
 
 	yaml "gopkg.in/yaml.v2"
@@ -106,5 +107,14 @@ func (m *yamlMarshaler) Unmarshal(data []byte, v interface{}) error {
 	// IDEA: use a "strict" marshaler, so that we can warn on unrecognized keys (avoiding silly mistakes).  We should
 	//     set aside an officially sanctioned area in the metadata for extensibility by 3rd parties.
 
-	return yaml.Unmarshal(data, v)
+	err := yaml.Unmarshal(data, v)
+	if err != nil {
+		// Return type errors directly
+		if _, ok := err.(*yaml.TypeError); ok {
+			return err
+		}
+		// Other errors will be parse errors due to invalid syntax
+		return fmt.Errorf("invalid YAML file: %w", err)
+	}
+	return nil
 }

tests/integration/integration_test.go

@@ -106,6 +106,36 @@ func TestStackTagValidation(t *testing.T) {
 	})
 }
 
+// TestStackInitValidation verifies various error scenarios related to init'ing a stack.
+func TestStackInitValidation(t *testing.T) {
+	t.Run("Error_InvalidStackYaml", func(t *testing.T) {
+		e := ptesting.NewEnvironment(t)
+		defer func() {
+			if !t.Failed() {
+				e.DeleteEnvironment()
+			}
+		}()
+		e.RunCommand("git", "init")
+
+		e.ImportDirectory("stack_project_name")
+		e.RunCommand("pulumi", "login", "--cloud-url", e.LocalURL())
+
+		// Starting a yaml value with a quote string and then more data is invalid
+		invalidYaml := "\"this is invalid\" yaml because of trailing data after quote string"
+
+		// Change the contents of the Description property of Pulumi.yaml.
+		yamlPath := filepath.Join(e.CWD, "Pulumi.yaml")
+		err := integration.ReplaceInFile("description: ", "description: "+invalidYaml, yamlPath)
+		assert.NoError(t, err)
+
+		stdout, stderr := e.RunCommandExpectError("pulumi", "stack", "init", "valid-name")
+		assert.Equal(t, "", stdout)
+		assert.Contains(t, stderr,
+			"error: could not get cloud url: could not load current project: "+
+				"invalid YAML file: yaml: line 1: did not find expected key")
+	})
+}
+
 // TestConfigSave ensures that config commands in the Pulumi CLI work as expected.
 func TestConfigSave(t *testing.T) {
 	e := ptesting.NewEnvironment(t)