When "dir:" attribute points to a non-existing dir, create it

Closes #209

task.go

@@ -200,6 +200,15 @@ func (e *Executor) RunTask(ctx context.Context, call taskfile.Call) error {
 		}
 	}
 
+	// When using the dir: attribute it can happen that the directory doesn't exist.
+	// If so, we create it.
+	if _, err := os.Stat(t.Dir); os.IsNotExist(err) {
+		if err := os.MkdirAll(t.Dir, 0755); err != nil {
+			e.Logger.Errf("cannot make directory %v: %v", t.Dir, err)
+			return err
+		}
+	}
+
 	for i := range t.Cmds {
 		if err := e.runCommand(ctx, t, call, i); err != nil {
 			if err2 := e.statusOnError(t); err2 != nil {

task_test.go

@@ -611,3 +611,29 @@ func TestWhenDirAttributeAndDirExistsItRunsInThatDir(t *testing.T) {
 	assert.Equal(t, expected, got, "Mismatch in the working directory")
 }
 
+func TestWhenDirAttributeItCreatesMissingAndRunsInThatDir(t *testing.T) {
+	const expected = "createme"
+	const dir = "testdata/dir/explicit_doesnt_exist/"
+	const toBeCreated = dir + expected
+	const target = "whereami"
+	var out bytes.Buffer
+	e := &task.Executor{
+		Dir:    dir,
+		Stdout: &out,
+		Stderr: &out,
+	}
+
+	// Ensure that the directory to be created doesn't actually exist.
+	_ = os.Remove(toBeCreated)
+	if _, err := os.Stat(toBeCreated); err == nil {
+		t.Errorf("Directory should not exist: %v", err)
+	}
+	assert.NoError(t, e.Setup())
+	assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: target}))
+
+	got := strings.TrimSuffix(filepath.Base(out.String()), "\n")
+	assert.Equal(t, expected, got, "Mismatch in the working directory")
+
+	// Clean-up after ourselves only if no error.
+	_ = os.Remove(toBeCreated)
+}

testdata/dir/explicit_doesnt_exist/Taskfile.yml

@@ -0,0 +1,8 @@
+version: '2'
+
+tasks:
+  whereami:
+    dir: createme
+    cmds:
+      - pwd
+    silent: true