refactor: convert taskfile.Merge into a method

taskfile/ast/taskfile.go

@@ -2,12 +2,16 @@ package ast
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/Masterminds/semver/v3"
 	"gopkg.in/yaml.v3"
 )
 
+// NamespaceSeparator contains the character that separates namespaces
+const NamespaceSeparator = ":"
+
 var V3 = semver.MustParse("3")
 
 // Taskfile is the abstract syntax tree for a Taskfile
@@ -28,6 +32,81 @@ type Taskfile struct {
 	Interval time.Duration
 }
 
+// Merge merges the second Taskfile into the first
+func (t1 *Taskfile) Merge(t2 *Taskfile, include *Include) error {
+	if !t1.Version.Equal(t2.Version) {
+		return fmt.Errorf(`task: Taskfiles versions should match. First is "%s" but second is "%s"`, t1.Version, t2.Version)
+	}
+	if t2.Output.IsSet() {
+		t1.Output = t2.Output
+	}
+
+	if t1.Vars == nil {
+		t1.Vars = &Vars{}
+	}
+	if t1.Env == nil {
+		t1.Env = &Vars{}
+	}
+	t1.Vars.Merge(t2.Vars)
+	t1.Env.Merge(t2.Env)
+
+	if err := t2.Tasks.Range(func(k string, v *Task) error {
+		// We do a deep copy of the task struct here to ensure that no data can
+		// be changed elsewhere once the taskfile is merged.
+		task := v.DeepCopy()
+
+		// Set the task to internal if EITHER the included task or the included
+		// taskfile are marked as internal
+		task.Internal = task.Internal || (include != nil && include.Internal)
+
+		// Add namespaces to dependencies, commands and aliases
+		for _, dep := range task.Deps {
+			if dep != nil && dep.Task != "" {
+				dep.Task = taskNameWithNamespace(dep.Task, include.Namespace)
+			}
+		}
+		for _, cmd := range task.Cmds {
+			if cmd != nil && cmd.Task != "" {
+				cmd.Task = taskNameWithNamespace(cmd.Task, include.Namespace)
+			}
+		}
+		for i, alias := range task.Aliases {
+			task.Aliases[i] = taskNameWithNamespace(alias, include.Namespace)
+		}
+		// Add namespace aliases
+		if include != nil {
+			for _, namespaceAlias := range include.Aliases {
+				task.Aliases = append(task.Aliases, taskNameWithNamespace(task.Task, namespaceAlias))
+				for _, alias := range v.Aliases {
+					task.Aliases = append(task.Aliases, taskNameWithNamespace(alias, namespaceAlias))
+				}
+			}
+		}
+
+		// Add the task to the merged taskfile
+		taskNameWithNamespace := taskNameWithNamespace(k, include.Namespace)
+		task.Task = taskNameWithNamespace
+		t1.Tasks.Set(taskNameWithNamespace, task)
+
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	// If the included Taskfile has a default task and the parent namespace has
+	// no task with a matching name, we can add an alias so that the user can
+	// run the included Taskfile's default task without specifying its full
+	// name. If the parent namespace has aliases, we add another alias for each
+	// of them.
+	if t2.Tasks.Get("default") != nil && t1.Tasks.Get(include.Namespace) == nil {
+		defaultTaskName := fmt.Sprintf("%s:default", include.Namespace)
+		t1.Tasks.Get(defaultTaskName).Aliases = append(t1.Tasks.Get(defaultTaskName).Aliases, include.Namespace)
+		t1.Tasks.Get(defaultTaskName).Aliases = append(t1.Tasks.Get(defaultTaskName).Aliases, include.Aliases...)
+	}
+
+	return nil
+}
+
 func (tf *Taskfile) UnmarshalYAML(node *yaml.Node) error {
 	switch node.Kind {
 	case yaml.MappingNode:
@@ -73,3 +152,10 @@ func (tf *Taskfile) UnmarshalYAML(node *yaml.Node) error {
 
 	return fmt.Errorf("yaml: line %d: cannot unmarshal %s into taskfile", node.Line, node.ShortTag())
 }
+
+func taskNameWithNamespace(taskName string, namespace string) string {
+	if strings.HasPrefix(taskName, NamespaceSeparator) {
+		return strings.TrimPrefix(taskName, NamespaceSeparator)
+	}
+	return fmt.Sprintf("%s%s%s", namespace, NamespaceSeparator, taskName)
+}

taskfile/reader.go

@@ -141,7 +141,7 @@ func Read(
 				}
 			}
 
-			if err = Merge(t, includedTaskfile, &include); err != nil {
+			if err = t.Merge(includedTaskfile, &include); err != nil {
 				return err
 			}