feat: error handling for undefined schema version (#1342)

* feat: error handling for undefined schema version

* docs: error codes

* chore: changelog

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## Unreleased
+
+- Fixed a nil pointer error when running a Taskfile with no contents (#1341,
+  #1342 by @pd93).
+- Added a new [exit code](https://taskfile.dev/api/#exit-codes) (107) for when a
+  Taskfile does not contain a schema version (#1342 by @pd93).
+
 ## v3.30.1 - 2023-09-14
 
 - Fixed a regression where some special variables weren't being set correctly

docs/docs/api_reference.md

@@ -70,6 +70,11 @@ A full list of the exit codes and their descriptions can be found below:
 | 100  | No Taskfile was found                                        |
 | 101  | A Taskfile already exists when trying to initialize one      |
 | 102  | The Taskfile is invalid or cannot be parsed                  |
+| 103  | A remote Taskfile could not be downlaoded                    |
+| 104  | A remote Taskfile was not trusted by the user                |
+| 105  | A remote Taskfile was could not be fetched securely          |
+| 106  | No cache was found for a remote Taskfile in offline mode     |
+| 107  | No schema version was defined in the Taskfile                |
 | 200  | The specified task could not be found                        |
 | 201  | An error occurred while executing a command inside of a task |
 | 202  | The user tried to invoke a task that is internal             |

errors/errors.go

@@ -17,6 +17,7 @@ const (
 	CodeTaskfileNotTrusted
 	CodeTaskfileNotSecure
 	CodeTaskfileCacheNotFound
+	CodeTaskfileVersionNotDefined
 )
 
 // Task related exit codes

errors/errors_taskfile.go

@@ -120,3 +120,20 @@ func (err *TaskfileCacheNotFound) Error() string {
 func (err *TaskfileCacheNotFound) Code() int {
 	return CodeTaskfileCacheNotFound
 }
+
+// TaskfileVersionNotDefined is returned when the user attempts to run a
+// Taskfile that does not contain a Taskfile schema version key.
+type TaskfileVersionNotDefined struct {
+	URI string
+}
+
+func (err *TaskfileVersionNotDefined) Error() string {
+	return fmt.Sprintf(
+		`task: Taskfile %q does not contain a schema version key`,
+		err.URI,
+	)
+}
+
+func (err *TaskfileVersionNotDefined) Code() int {
+	return CodeTaskfileVersionNotDefined
+}

taskfile/read/taskfile.go

@@ -147,6 +147,11 @@ func Taskfile(
 			return nil, err
 		}
 
+		// Check that the Taskfile is set and has a schema version
+		if t == nil || t.Version == nil {
+			return nil, &errors.TaskfileVersionNotDefined{URI: node.Location()}
+		}
+
 		// Annotate any included Taskfile reference with a base directory for resolving relative paths
 		if node, isFileNode := node.(*FileNode); isFileNode {
 			_ = t.Includes.Range(func(key string, includedFile taskfile.IncludedTaskfile) error {