Resolve relative include paths relative to the including Taskfile

Closes #823
Closes #822

taskfile/read/taskfile.go

@@ -9,7 +9,6 @@ import (
 
 	"gopkg.in/yaml.v3"
 
-	"github.com/go-task/task/v3/internal/execext"
 	"github.com/go-task/task/v3/internal/templater"
 	"github.com/go-task/task/v3/taskfile"
 )
@@ -44,6 +43,7 @@ func Taskfile(readerNode *ReaderNode) (*taskfile.Taskfile, error) {
 		}
 		readerNode.Dir = d
 	}
+
 	path, err := exists(filepath.Join(readerNode.Dir, readerNode.Entrypoint))
 	if err != nil {
 		return nil, err
@@ -60,6 +60,16 @@ func Taskfile(readerNode *ReaderNode) (*taskfile.Taskfile, error) {
 		return nil, err
 	}
 
+	// Annotate any included Taskfile reference with a base directory for resolving relative paths
+	_ = t.Includes.Range(func(key string, includedFile taskfile.IncludedTaskfile) error {
+		// Set the base directory for resolving relative paths, but only if not already set
+		if includedFile.BaseDir == "" {
+			includedFile.BaseDir = readerNode.Dir
+			t.Includes.Set(key, includedFile)
+		}
+		return nil
+	})
+
 	err = t.Includes.Range(func(namespace string, includedTask taskfile.IncludedTaskfile) error {
 		if v >= 3.0 {
 			tr := templater.Templater{Vars: &taskfile.Vars{}, RemoveNoValue: true}
@@ -69,19 +79,18 @@ func Taskfile(readerNode *ReaderNode) (*taskfile.Taskfile, error) {
 				Optional:       includedTask.Optional,
 				AdvancedImport: includedTask.AdvancedImport,
 				Vars:           includedTask.Vars,
+				BaseDir:        includedTask.BaseDir,
 			}
 			if err := tr.Err(); err != nil {
 				return err
 			}
 		}
 
-		path, err := execext.Expand(includedTask.Taskfile)
+		path, err := includedTask.FullTaskfilePath()
 		if err != nil {
 			return err
 		}
-		if !filepath.IsAbs(path) {
-			path = filepath.Join(readerNode.Dir, path)
-		}
+
 		path, err = exists(path)
 		if err != nil {
 			if includedTask.Optional {
@@ -114,21 +123,27 @@ func Taskfile(readerNode *ReaderNode) (*taskfile.Taskfile, error) {
 		}
 
 		if includedTask.AdvancedImport {
+			dir, err := includedTask.FullDirPath()
+			if err != nil {
+				return err
+			}
+
 			for k, v := range includedTaskfile.Vars.Mapping {
 				o := v
-				o.Dir = filepath.Join(readerNode.Dir, includedTask.Dir)
+				o.Dir = dir
 				includedTaskfile.Vars.Mapping[k] = o
 			}
 			for k, v := range includedTaskfile.Env.Mapping {
 				o := v
-				o.Dir = filepath.Join(readerNode.Dir, includedTask.Dir)
+				o.Dir = dir
 				includedTaskfile.Env.Mapping[k] = o
 			}
 
 			for _, task := range includedTaskfile.Tasks {
 				if !filepath.IsAbs(task.Dir) {
-					task.Dir = filepath.Join(includedTask.Dir, task.Dir)
+					task.Dir = filepath.Join(dir, task.Dir)
 				}
+
 				task.IncludeVars = includedTask.Vars
 				task.IncludedTaskfileVars = includedTaskfile.Vars
 			}
@@ -176,19 +191,29 @@ func readTaskfile(file string) (*taskfile.Taskfile, error) {
 	return &t, yaml.NewDecoder(f).Decode(&t)
 }
 
+// exists finds a Taskfile at the stated location, returning a fully qualified path to the file
 func exists(path string) (string, error) {
 	fi, err := os.Stat(path)
 	if err != nil {
 		return "", err
 	}
 	if fi.Mode().IsRegular() {
-		return path, nil
+		// File exists, return a fully qualified path
+		result, err := filepath.Abs(path)
+		if err != nil {
+			return "", err
+		}
+		return result, nil
 	}
 
 	for _, n := range defaultTaskfiles {
 		fpath := filepath.Join(path, n)
 		if _, err := os.Stat(fpath); err == nil {
-			return fpath, nil
+			result, err := filepath.Abs(fpath)
+			if err != nil {
+				return "", err
+			}
+			return result, nil
 		}
 	}