Improve YAML parse error reporting

Fixes #467

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+- Improve error reporting when parsing YAML: in some situations where you
+  would just see an generic error, you'll now see the actual error with
+  more detail: the YAML line the failed to parse, for exemple
+  [#467](https://github.com/go-task/task/issues/467).
 - A JSON Schema was published [here](https://json.schemastore.org/taskfile.json)
 - and is automatically being used by some editors like Visual Studio Code
   ([#135](https://github.com/go-task/task/issues/135)).

taskfile/cmd.go

@@ -1,7 +1,6 @@
 package taskfile
 
 import (
-	"errors"
 	"strings"
 )
 
@@ -20,13 +19,6 @@ type Dep struct {
 	Vars *Vars
 }
 
-var (
-	// ErrCantUnmarshalCmd is returned for invalid command YAML
-	ErrCantUnmarshalCmd = errors.New("task: can't unmarshal cmd value")
-	// ErrCantUnmarshalDep is returned for invalid dependency YAML
-	ErrCantUnmarshalDep = errors.New("task: can't unmarshal dep value")
-)
-
 // UnmarshalYAML implements yaml.Unmarshaler interface
 func (c *Cmd) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	var cmd string
@@ -53,13 +45,13 @@ func (c *Cmd) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		Task string
 		Vars *Vars
 	}
-	if err := unmarshal(&taskCall); err == nil {
+	if err := unmarshal(&taskCall); err != nil {
+		return err
+	}
 	c.Task = taskCall.Task
 	c.Vars = taskCall.Vars
 	return nil
 }
-	return ErrCantUnmarshalCmd
-}
 
 // UnmarshalYAML implements yaml.Unmarshaler interface
 func (d *Dep) UnmarshalYAML(unmarshal func(interface{}) error) error {
@@ -72,10 +64,10 @@ func (d *Dep) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		Task string
 		Vars *Vars
 	}
-	if err := unmarshal(&taskCall); err == nil {
+	if err := unmarshal(&taskCall); err != nil {
+		return err
+	}
 	d.Task = taskCall.Task
 	d.Vars = taskCall.Vars
 	return nil
 }
-	return ErrCantUnmarshalDep
-}

taskfile/included_taskfile.go

@@ -6,11 +6,6 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-var (
-	// ErrCantUnmarshalIncludedTaskfile is returned for invalid var YAML.
-	ErrCantUnmarshalIncludedTaskfile = errors.New("task: can't unmarshal included value")
-)
-
 // IncludedTaskfile represents information about included tasksfile
 type IncludedTaskfile struct {
 	Taskfile       string
@@ -98,12 +93,11 @@ func (it *IncludedTaskfile) UnmarshalYAML(unmarshal func(interface{}) error) err
 		Taskfile string
 		Dir      string
 	}
-	if err := unmarshal(&includedTaskfile); err == nil {
+	if err := unmarshal(&includedTaskfile); err != nil {
+		return err
+	}
 	it.Dir = includedTaskfile.Dir
 	it.Taskfile = includedTaskfile.Taskfile
 	it.AdvancedImport = true
 	return nil
 }
-
-	return ErrCantUnmarshalIncludedTaskfile
-}

taskfile/task.go

@@ -1,9 +1,5 @@
 package taskfile
 
-import (
-	"errors"
-)
-
 // Tasks represents a group of tasks
 type Tasks map[string]*Task
 
@@ -28,11 +24,6 @@ type Task struct {
 	IgnoreError   bool
 }
 
-var (
-	// ErrCantUnmarshalTask is returned for invalid task YAML
-	ErrCantUnmarshalTask = errors.New("task: can't unmarshal task value")
-)
-
 func (t *Task) Name() string {
 	if t.Label != "" {
 		return t.Label
@@ -71,7 +62,9 @@ func (t *Task) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		Prefix        string
 		IgnoreError   bool `yaml:"ignore_error"`
 	}
-	if err := unmarshal(&task); err == nil {
+	if err := unmarshal(&task); err != nil {
+		return err
+	}
 	t.Cmds = task.Cmds
 	t.Deps = task.Deps
 	t.Label = task.Label
@@ -88,9 +81,5 @@ func (t *Task) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	t.Method = task.Method
 	t.Prefix = task.Prefix
 	t.IgnoreError = task.IgnoreError
-
 	return nil
 }
-
-	return ErrCantUnmarshalTask
-}

taskfile/var.go

@@ -7,11 +7,6 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
-var (
-	// ErrCantUnmarshalVar is returned for invalid var YAML.
-	ErrCantUnmarshalVar = errors.New("task: can't unmarshal var value")
-)
-
 // Vars is a string[string] variables map.
 type Vars struct {
 	Keys    []string
@@ -124,10 +119,9 @@ func (v *Var) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	var sh struct {
 		Sh string
 	}
-	if err := unmarshal(&sh); err == nil {
+	if err := unmarshal(&sh); err != nil {
+		return err
+	}
 	v.Sh = sh.Sh
 	return nil
 }
-
-	return ErrCantUnmarshalVar
-}