Merge pull request #311 from go-task/vars-refactor-for-v3

v3: Variables refactoring

cmd/task/task.go

@@ -148,9 +148,7 @@ func main() {
 	}
 
 	calls, globals := args.Parse(pflag.Args()...)
-	for name, value := range globals {
-		e.Taskfile.Vars[name] = value
-	}
+	e.Taskfile.Vars.Merge(globals)
 
 	ctx := context.Background()
 	if !watch {

go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/spf13/pflag v1.0.3
 	github.com/stretchr/testify v1.5.1
 	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e
-	gopkg.in/yaml.v2 v2.2.2
+	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c
 	mvdan.cc/sh/v3 v3.1.0
 )
 

go.sum

@@ -59,6 +59,8 @@ gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 mvdan.cc/editorconfig v0.1.1-0.20200121172147-e40951bde157/go.mod h1:Ge4atmRUYqueGppvJ7JNrtqpqokoJEFxYbP0Z+WeKS8=
 mvdan.cc/sh/v3 v3.1.0 h1:bFxsEzIubuABloc8G1Ko78rbZZ0JspNN9e9+R/w3z5k=
 mvdan.cc/sh/v3 v3.1.0/go.mod h1:F+Vm4ZxPJxDKExMLhvjuI50oPnedVXpfjNSrusiTOno=

internal/args/args.go

@@ -7,9 +7,9 @@ import (
 )
 
 // Parse parses command line argument: tasks and vars of each task
-func Parse(args ...string) ([]taskfile.Call, taskfile.Vars) {
+func Parse(args ...string) ([]taskfile.Call, *taskfile.Vars) {
 	var calls []taskfile.Call
-	var globals taskfile.Vars
+	var globals *taskfile.Vars
 
 	for _, arg := range args {
 		if !strings.Contains(arg, "=") {
@@ -19,18 +19,16 @@ func Parse(args ...string) ([]taskfile.Call, taskfile.Vars) {
 
 		if len(calls) < 1 {
 			if globals == nil {
-				globals = taskfile.Vars{}
+				globals = &taskfile.Vars{}
 			}
-
 			name, value := splitVar(arg)
-			globals[name] = taskfile.Var{Static: value}
+			globals.Set(name, taskfile.Var{Static: value})
 		} else {
 			if calls[len(calls)-1].Vars == nil {
-				calls[len(calls)-1].Vars = make(taskfile.Vars)
+				calls[len(calls)-1].Vars = &taskfile.Vars{}
 			}
-
-			name, value := splitVar((arg))
-			calls[len(calls)-1].Vars[name] = taskfile.Var{Static: value}
+			name, value := splitVar(arg)
+			calls[len(calls)-1].Vars.Set(name, taskfile.Var{Static: value})
 		}
 	}
 

internal/args/args_test.go

@@ -14,7 +14,7 @@ func TestArgs(t *testing.T) {
 	tests := []struct {
 		Args            []string
 		ExpectedCalls   []taskfile.Call
-		ExpectedGlobals taskfile.Vars
+		ExpectedGlobals *taskfile.Vars
 	}{
 		{
 			Args: []string{"task-a", "task-b", "task-c"},
@@ -29,16 +29,22 @@ func TestArgs(t *testing.T) {
 			ExpectedCalls: []taskfile.Call{
 				{
 					Task: "task-a",
-					Vars: taskfile.Vars{
-						"FOO": taskfile.Var{Static: "bar"},
+					Vars: &taskfile.Vars{
+						Keys: []string{"FOO"},
+						Mapping: map[string]taskfile.Var{
+							"FOO": taskfile.Var{Static: "bar"},
+						},
 					},
 				},
 				{Task: "task-b"},
 				{
 					Task: "task-c",
-					Vars: taskfile.Vars{
-						"BAR": taskfile.Var{Static: "baz"},
-						"BAZ": taskfile.Var{Static: "foo"},
+					Vars: &taskfile.Vars{
+						Keys: []string{"BAR", "BAZ"},
+						Mapping: map[string]taskfile.Var{
+							"BAR": taskfile.Var{Static: "baz"},
+							"BAZ": taskfile.Var{Static: "foo"},
+						},
 					},
 				},
 			},
@@ -48,8 +54,11 @@ func TestArgs(t *testing.T) {
 			ExpectedCalls: []taskfile.Call{
 				{
 					Task: "task-a",
-					Vars: taskfile.Vars{
-						"CONTENT": taskfile.Var{Static: "with some spaces"},
+					Vars: &taskfile.Vars{
+						Keys: []string{"CONTENT"},
+						Mapping: map[string]taskfile.Var{
+							"CONTENT": taskfile.Var{Static: "with some spaces"},
+						},
 					},
 				},
 			},
@@ -60,8 +69,11 @@ func TestArgs(t *testing.T) {
 				{Task: "task-a"},
 				{Task: "task-b"},
 			},
-			ExpectedGlobals: taskfile.Vars{
-				"FOO": {Static: "bar"},
+			ExpectedGlobals: &taskfile.Vars{
+				Keys: []string{"FOO"},
+				Mapping: map[string]taskfile.Var{
+					"FOO": {Static: "bar"},
+				},
 			},
 		},
 		{
@@ -81,9 +93,12 @@ func TestArgs(t *testing.T) {
 			ExpectedCalls: []taskfile.Call{
 				{Task: "default"},
 			},
-			ExpectedGlobals: taskfile.Vars{
-				"FOO": {Static: "bar"},
-				"BAR": {Static: "baz"},
+			ExpectedGlobals: &taskfile.Vars{
+				Keys: []string{"FOO", "BAR"},
+				Mapping: map[string]taskfile.Var{
+					"FOO": {Static: "bar"},
+					"BAR": {Static: "baz"},
+				},
 			},
 		},
 	}

internal/compiler/compiler.go

@@ -7,6 +7,6 @@ import (
 // Compiler handles compilation of a task before its execution.
 // E.g. variable merger, template processing, etc.
 type Compiler interface {
-	GetVariables(t *taskfile.Task, call taskfile.Call) (taskfile.Vars, error)
+	GetVariables(t *taskfile.Task, call taskfile.Call) (*taskfile.Vars, error)
 	HandleDynamicVar(v taskfile.Var) (string, error)
 }

internal/compiler/env.go

@@ -9,16 +9,12 @@ import (
 
 // GetEnviron the all return all environment variables encapsulated on a
 // taskfile.Vars
-func GetEnviron() taskfile.Vars {
-	var (
-		env = os.Environ()
-		m   = make(taskfile.Vars, len(env))
-	)
-
-	for _, e := range env {
+func GetEnviron() *taskfile.Vars {
+	m := &taskfile.Vars{}
+	for _, e := range os.Environ() {
 		keyVal := strings.SplitN(e, "=", 2)
 		key, val := keyVal[0], keyVal[1]
-		m[key] = taskfile.Var{Static: val}
+		m.Set(key, taskfile.Var{Static: val})
 	}
 	return m
 }

internal/compiler/v2/compiler_v2.go

@@ -19,8 +19,8 @@ var _ compiler.Compiler = &CompilerV2{}
 type CompilerV2 struct {
 	Dir string
 
-	Taskvars     taskfile.Vars
-	TaskfileVars taskfile.Vars
+	Taskvars     *taskfile.Vars
+	TaskfileVars *taskfile.Vars
 
 	Expansions int
 
@@ -36,10 +36,10 @@ type CompilerV2 struct {
 // 3. Taskfile variables
 // 4. Taskvars file variables
 // 5. Environment variables
-func (c *CompilerV2) GetVariables(t *taskfile.Task, call taskfile.Call) (taskfile.Vars, error) {
+func (c *CompilerV2) GetVariables(t *taskfile.Task, call taskfile.Call) (*taskfile.Vars, error) {
 	vr := varResolver{c: c, vars: compiler.GetEnviron()}
-	vr.vars["TASK"] = taskfile.Var{Static: t.Task}
-	for _, vars := range []taskfile.Vars{c.Taskvars, c.TaskfileVars, call.Vars, t.Vars} {
+	vr.vars.Set("TASK", taskfile.Var{Static: t.Task})
+	for _, vars := range []*taskfile.Vars{c.Taskvars, c.TaskfileVars, call.Vars, t.Vars} {
 		for i := 0; i < c.Expansions; i++ {
 			vr.merge(vars)
 		}
@@ -49,16 +49,16 @@ func (c *CompilerV2) GetVariables(t *taskfile.Task, call taskfile.Call) (taskfil
 
 type varResolver struct {
 	c    *CompilerV2
-	vars taskfile.Vars
+	vars *taskfile.Vars
 	err  error
 }
 
-func (vr *varResolver) merge(vars taskfile.Vars) {
+func (vr *varResolver) merge(vars *taskfile.Vars) {
 	if vr.err != nil {
 		return
 	}
 	tr := templater.Templater{Vars: vr.vars}
-	for k, v := range vars {
+	vars.Range(func(k string, v taskfile.Var) error {
 		v = taskfile.Var{
 			Static: tr.Replace(v.Static),
 			Sh:     tr.Replace(v.Sh),
@@ -66,10 +66,11 @@ func (vr *varResolver) merge(vars taskfile.Vars) {
 		static, err := vr.c.HandleDynamicVar(v)
 		if err != nil {
 			vr.err = err
-			return
+			return err
 		}
-		vr.vars[k] = taskfile.Var{Static: static}
-	}
+		vr.vars.Set(k, taskfile.Var{Static: static})
+		return nil
+	})
 	vr.err = tr.Err()
 }
 

internal/compiler/v3/compiler_v3.go

@@ -0,0 +1,98 @@
+package v3
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/go-task/task/v2/internal/compiler"
+	"github.com/go-task/task/v2/internal/execext"
+	"github.com/go-task/task/v2/internal/logger"
+	"github.com/go-task/task/v2/internal/taskfile"
+	"github.com/go-task/task/v2/internal/templater"
+)
+
+var _ compiler.Compiler = &CompilerV3{}
+
+type CompilerV3 struct {
+	Dir string
+
+	TaskfileVars *taskfile.Vars
+
+	Logger *logger.Logger
+
+	dynamicCache   map[string]string
+	muDynamicCache sync.Mutex
+}
+
+func (c *CompilerV3) GetVariables(t *taskfile.Task, call taskfile.Call) (*taskfile.Vars, error) {
+	result := compiler.GetEnviron()
+	result.Set("TASK", taskfile.Var{Static: t.Task})
+
+	rangeFunc := func(k string, v taskfile.Var) error {
+		tr := templater.Templater{Vars: result, RemoveNoValue: true}
+		v = taskfile.Var{
+			Static: tr.Replace(v.Static),
+			Sh:     tr.Replace(v.Sh),
+		}
+		if err := tr.Err(); err != nil {
+			return err
+		}
+		static, err := c.HandleDynamicVar(v)
+		if err != nil {
+			return err
+		}
+		result.Set(k, taskfile.Var{Static: static})
+		return nil
+	}
+
+	if err := c.TaskfileVars.Range(rangeFunc); err != nil {
+		return nil, err
+	}
+	if err := call.Vars.Range(rangeFunc); err != nil {
+		return nil, err
+	}
+	if err := t.Vars.Range(rangeFunc); err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}
+
+func (c *CompilerV3) HandleDynamicVar(v taskfile.Var) (string, error) {
+	if v.Static != "" || v.Sh == "" {
+		return v.Static, nil
+	}
+
+	c.muDynamicCache.Lock()
+	defer c.muDynamicCache.Unlock()
+
+	if c.dynamicCache == nil {
+		c.dynamicCache = make(map[string]string, 30)
+	}
+	if result, ok := c.dynamicCache[v.Sh]; ok {
+		return result, nil
+	}
+
+	var stdout bytes.Buffer
+	opts := &execext.RunCommandOptions{
+		Command: v.Sh,
+		Dir:     c.Dir,
+		Stdout:  &stdout,
+		Stderr:  c.Logger.Stderr,
+	}
+	if err := execext.RunCommand(context.Background(), opts); err != nil {
+		return "", fmt.Errorf(`task: Command "%s" in taskvars file failed: %s`, opts.Command, err)
+	}
+
+	// Trim a single trailing newline from the result to make most command
+	// output easier to use in shell commands.
+	result := strings.TrimSuffix(stdout.String(), "\n")
+
+	c.dynamicCache[v.Sh] = result
+	c.Logger.VerboseErrf(logger.Magenta, `task: dynamic variable: '%s' result: '%s'`, v.Sh, result)
+
+	return result, nil
+}

internal/taskfile/call.go

@@ -3,5 +3,5 @@ package taskfile
 // Call is the parameters to a task call
 type Call struct {
 	Task string
-	Vars Vars
+	Vars *Vars
 }

internal/taskfile/cmd.go

@@ -10,14 +10,14 @@ type Cmd struct {
 	Cmd         string
 	Silent      bool
 	Task        string
-	Vars        Vars
+	Vars        *Vars
 	IgnoreError bool
 }
 
 // Dep is a task dependency
 type Dep struct {
 	Task string
-	Vars Vars
+	Vars *Vars
 }
 
 var (
@@ -51,7 +51,7 @@ func (c *Cmd) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	}
 	var taskCall struct {
 		Task string
-		Vars Vars
+		Vars *Vars
 	}
 	if err := unmarshal(&taskCall); err == nil {
 		c.Task = taskCall.Task
@@ -70,7 +70,7 @@ func (d *Dep) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	}
 	var taskCall struct {
 		Task string
-		Vars Vars
+		Vars *Vars
 	}
 	if err := unmarshal(&taskCall); err == nil {
 		d.Task = taskCall.Task

internal/taskfile/merge.go

@@ -29,18 +29,13 @@ func Merge(t1, t2 *Taskfile, namespaces ...string) error {
 	}
 
 	if t1.Vars == nil {
-		t1.Vars = make(Vars)
+		t1.Vars = &Vars{}
 	}
-	for k, v := range t2.Vars {
-		t1.Vars[k] = v
-	}
-
 	if t1.Env == nil {
-		t1.Env = make(Vars)
-	}
-	for k, v := range t2.Env {
-		t1.Env[k] = v
+		t1.Env = &Vars{}
 	}
+	t1.Vars.Merge(t2.Vars)
+	t1.Env.Merge(t2.Env)
 
 	if t1.Tasks == nil {
 		t1.Tasks = make(Tasks)

internal/taskfile/precondition_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/go-task/task/v2/internal/taskfile"
 
 	"github.com/stretchr/testify/assert"
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 func TestPreconditionParse(t *testing.T) {

internal/taskfile/read/taskfile.go

@@ -9,7 +9,7 @@ import (
 
 	"github.com/go-task/task/v2/internal/taskfile"
 
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 var (

internal/taskfile/read/taskvars.go

@@ -8,12 +8,12 @@ import (
 
 	"github.com/go-task/task/v2/internal/taskfile"
 
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 // Taskvars reads a Taskvars for a given directory
-func Taskvars(dir string) (taskfile.Vars, error) {
-	vars := make(taskfile.Vars)
+func Taskvars(dir string) (*taskfile.Vars, error) {
+	vars := &taskfile.Vars{}
 
 	path := filepath.Join(dir, "Taskvars.yml")
 	if _, err := os.Stat(path); err == nil {
@@ -29,24 +29,17 @@ func Taskvars(dir string) (taskfile.Vars, error) {
 		if err != nil {
 			return nil, err
 		}
-
-		if vars == nil {
-			vars = osVars
-		} else {
-			for k, v := range osVars {
-				vars[k] = v
-			}
-		}
+		vars.Merge(osVars)
 	}
 
 	return vars, nil
 }
 
-func readTaskvars(file string) (taskfile.Vars, error) {
+func readTaskvars(file string) (*taskfile.Vars, error) {
 	f, err := os.Open(file)
 	if err != nil {
 		return nil, err
 	}
 	var vars taskfile.Vars
-	return vars, yaml.NewDecoder(f).Decode(&vars)
+	return &vars, yaml.NewDecoder(f).Decode(&vars)
 }

internal/taskfile/task.go

@@ -19,8 +19,8 @@ type Task struct {
 	Status        []string
 	Preconditions []*Precondition
 	Dir           string
-	Vars          Vars
-	Env           Vars
+	Vars          *Vars
+	Env           *Vars
 	Silent        bool
 	Method        string
 	Prefix        string
@@ -55,8 +55,8 @@ func (t *Task) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		Status        []string
 		Preconditions []*Precondition
 		Dir           string
-		Vars          Vars
-		Env           Vars
+		Vars          *Vars
+		Env           *Vars
 		Silent        bool
 		Method        string
 		Prefix        string

internal/taskfile/taskfile.go

@@ -7,8 +7,8 @@ type Taskfile struct {
 	Output     string
 	Method     string
 	Includes   IncludedTaskfiles
-	Vars       Vars
-	Env        Vars
+	Vars       *Vars
+	Env        *Vars
 	Tasks      Tasks
 	Silent     bool
 }
@@ -21,8 +21,8 @@ func (tf *Taskfile) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		Output     string
 		Method     string
 		Includes   IncludedTaskfiles
-		Vars       Vars
-		Env        Vars
+		Vars       *Vars
+		Env        *Vars
 		Tasks      Tasks
 		Silent     bool
 	}
@@ -42,7 +42,10 @@ func (tf *Taskfile) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		tf.Expansions = 2
 	}
 	if tf.Vars == nil {
-		tf.Vars = make(Vars)
+		tf.Vars = &Vars{}
+	}
+	if tf.Env == nil {
+		tf.Env = &Vars{}
 	}
 	return nil
 }

internal/taskfile/taskfile_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/go-task/task/v2/internal/taskfile"
 
 	"github.com/stretchr/testify/assert"
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 func TestCmdParse(t *testing.T) {
@@ -33,9 +33,12 @@ vars:
 		{
 			yamlTaskCall,
 			&taskfile.Cmd{},
-			&taskfile.Cmd{Task: "another-task", Vars: taskfile.Vars{
-				"PARAM1": taskfile.Var{Static: "VALUE1"},
-				"PARAM2": taskfile.Var{Static: "VALUE2"},
+			&taskfile.Cmd{Task: "another-task", Vars: &taskfile.Vars{
+				Keys: []string{"PARAM1", "PARAM2"},
+				Mapping: map[string]taskfile.Var{
+					"PARAM1": taskfile.Var{Static: "VALUE1"},
+					"PARAM2": taskfile.Var{Static: "VALUE2"},
+				},
 			}},
 		},
 		{
@@ -46,9 +49,12 @@ vars:
 		{
 			yamlTaskCall,
 			&taskfile.Dep{},
-			&taskfile.Dep{Task: "another-task", Vars: taskfile.Vars{
-				"PARAM1": taskfile.Var{Static: "VALUE1"},
-				"PARAM2": taskfile.Var{Static: "VALUE2"},
+			&taskfile.Dep{Task: "another-task", Vars: &taskfile.Vars{
+				Keys: []string{"PARAM1", "PARAM2"},
+				Mapping: map[string]taskfile.Var{
+					"PARAM1": taskfile.Var{Static: "VALUE1"},
+					"PARAM2": taskfile.Var{Static: "VALUE2"},
+				},
 			}},
 		},
 	}

internal/taskfile/var.go

@@ -3,6 +3,8 @@ package taskfile
 import (
 	"errors"
 	"strings"
+
+	"gopkg.in/yaml.v3"
 )
 
 var (
@@ -11,17 +13,83 @@ var (
 )
 
 // Vars is a string[string] variables map.
-type Vars map[string]Var
+type Vars struct {
+	Keys    []string
+	Mapping map[string]Var
+}
+
+// UnmarshalYAML implements the yaml.Unmarshaler interface.
+func (vs *Vars) UnmarshalYAML(node *yaml.Node) error {
+	if node.Kind != yaml.MappingNode {
+		return errors.New("task: vars is not a map")
+	}
+
+	// NOTE(@andreynering): on this style of custom unmarsheling,
+	// even number contains the keys, while odd numbers contains
+	// the values.
+	for i := 0; i < len(node.Content); i += 2 {
+		keyNode := node.Content[i]
+		valueNode := node.Content[i+1]
+
+		var v Var
+		if err := valueNode.Decode(&v); err != nil {
+			return err
+		}
+		vs.Set(keyNode.Value, v)
+	}
+	return nil
+}
+
+// Merge merges the given Vars into the caller one
+func (vs *Vars) Merge(other *Vars) {
+	other.Range(func(key string, value Var) error {
+		vs.Set(key, value)
+		return nil
+	})
+}
+
+// Set sets a value to a given key
+func (vs *Vars) Set(key string, value Var) {
+	if vs.Mapping == nil {
+		vs.Mapping = make(map[string]Var, 1)
+	}
+	if !strSliceContains(vs.Keys, key) {
+		vs.Keys = append(vs.Keys, key)
+	}
+	vs.Mapping[key] = value
+}
+
+func strSliceContains(s []string, str string) bool {
+	for _, v := range s {
+		if v == str {
+			return true
+		}
+	}
+	return false
+}
+
+// Range allows you to loop into the vars in its right order
+func (vs *Vars) Range(yield func(key string, value Var) error) error {
+	if vs == nil {
+		return nil
+	}
+	for _, k := range vs.Keys {
+		if err := yield(k, vs.Mapping[k]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
 
 // ToCacheMap converts Vars to a map containing only the static
 // variables
-func (vs Vars) ToCacheMap() (m map[string]interface{}) {
-	m = make(map[string]interface{}, len(vs))
-	for k, v := range vs {
+func (vs *Vars) ToCacheMap() (m map[string]interface{}) {
+	m = make(map[string]interface{}, len(vs.Keys))
+	vs.Range(func(k string, v Var) error {
 		if v.Sh != "" {
 			// Dynamic variable is not yet resolved; trigger
 			// <no value> to be used in templates.
-			continue
+			return nil
 		}
 
 		if v.Live != nil {
@@ -29,7 +97,8 @@ func (vs Vars) ToCacheMap() (m map[string]interface{}) {
 		} else {
 			m[k] = v.Static
 		}
-	}
+		return nil
+	})
 	return
 }
 

internal/templater/templater.go

@@ -2,6 +2,7 @@ package templater
 
 import (
 	"bytes"
+	"strings"
 	"text/template"
 
 	"github.com/go-task/task/v2/internal/taskfile"
@@ -12,7 +13,8 @@ import (
 // happen will be assigned to r.err, and consecutive calls to funcs will just
 // return the zero value.
 type Templater struct {
-	Vars taskfile.Vars
+	Vars          *taskfile.Vars
+	RemoveNoValue bool
 
 	cacheMap map[string]interface{}
 	err      error
@@ -42,6 +44,9 @@ func (r *Templater) Replace(str string) string {
 		r.err = err
 		return ""
 	}
+	if r.RemoveNoValue {
+		return strings.ReplaceAll(b.String(), "<no value>", "")
+	}
 	return b.String()
 }
 
@@ -57,20 +62,22 @@ func (r *Templater) ReplaceSlice(strs []string) []string {
 	return new
 }
 
-func (r *Templater) ReplaceVars(vars taskfile.Vars) taskfile.Vars {
-	if r.err != nil || len(vars) == 0 {
+func (r *Templater) ReplaceVars(vars *taskfile.Vars) *taskfile.Vars {
+	if r.err != nil || vars == nil || len(vars.Keys) == 0 {
 		return nil
 	}
 
-	new := make(taskfile.Vars, len(vars))
-	for k, v := range vars {
-		new[k] = taskfile.Var{
+	var new taskfile.Vars
+	vars.Range(func(k string, v taskfile.Var) error {
+		new.Set(k, taskfile.Var{
 			Static: r.Replace(v.Static),
 			Live:   v.Live,
 			Sh:     r.Replace(v.Sh),
-		}
-	}
-	return new
+		})
+		return nil
+	})
+
+	return &new
 }
 
 func (r *Templater) Err() error {

task.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/go-task/task/v2/internal/compiler"
 	compilerv2 "github.com/go-task/task/v2/internal/compiler/v2"
+	compilerv3 "github.com/go-task/task/v2/internal/compiler/v3"
 	"github.com/go-task/task/v2/internal/execext"
 	"github.com/go-task/task/v2/internal/logger"
 	"github.com/go-task/task/v2/internal/output"
@@ -52,7 +53,7 @@ type Executor struct {
 	Output      output.Output
 	OutputStyle string
 
-	taskvars taskfile.Vars
+	taskvars *taskfile.Vars
 
 	taskCallCount map[string]*int32
 	mkdirMutexMap map[string]*sync.Mutex
@@ -131,9 +132,9 @@ func (e *Executor) Setup() error {
 		Color:   e.Color,
 	}
 
-	v, err := strconv.ParseFloat(e.Taskfile.Version, 64)
+	v, err := e.parsedVersion()
 	if err != nil {
-		return fmt.Errorf(`task: Could not parse taskfile version "%s": %v`, e.Taskfile.Version, err)
+
 	}
 
 	if v < 2 {
@@ -154,12 +155,20 @@ func (e *Executor) Setup() error {
 		e.Logger.Color = false
 	}
 
-	e.Compiler = &compilerv2.CompilerV2{
-		Dir:          e.Dir,
-		Taskvars:     e.taskvars,
-		TaskfileVars: e.Taskfile.Vars,
-		Expansions:   e.Taskfile.Expansions,
-		Logger:       e.Logger,
+	if v < 3 {
+		e.Compiler = &compilerv2.CompilerV2{
+			Dir:          e.Dir,
+			Taskvars:     e.taskvars,
+			TaskfileVars: e.Taskfile.Vars,
+			Expansions:   e.Taskfile.Expansions,
+			Logger:       e.Logger,
+		}
+	} else {
+		e.Compiler = &compilerv3.CompilerV3{
+			Dir:          e.Dir,
+			TaskfileVars: e.Taskfile.Vars,
+			Logger:       e.Logger,
+		}
 	}
 
 	if v < 2.1 && e.Taskfile.Output != "" {
@@ -231,6 +240,14 @@ func (e *Executor) Setup() error {
 	return nil
 }
 
+func (e *Executor) parsedVersion() (float64, error) {
+	v, err := strconv.ParseFloat(e.Taskfile.Version, 64)
+	if err != nil {
+		return 0, fmt.Errorf(`task: Could not parse taskfile version "%s": %v`, e.Taskfile.Version, err)
+	}
+	return v, nil
+}
+
 // RunTask runs a task by its name
 func (e *Executor) RunTask(ctx context.Context, call taskfile.Call) error {
 	t, err := e.CompiledTask(call)

task_test.go

@@ -107,6 +107,20 @@ func TestVarsV2(t *testing.T) {
 	tt.Run(t)
 }
 
+func TestVarsV3(t *testing.T) {
+	tt := fileContentTest{
+		Dir:    "testdata/vars/v3",
+		Target: "default",
+		Files: map[string]string{
+			"missing-var.txt":  "\n",
+			"var-order.txt":    "ABCDEF\n",
+			"dependent-sh.txt": "123456\n",
+			"with-call.txt":    "Hi, ABC123!\n",
+		},
+	}
+	tt.Run(t)
+}
+
 func TestMultilineVars(t *testing.T) {
 	for _, dir := range []string{"testdata/vars/v2/multiline"} {
 		tt := fileContentTest{

testdata/checksum/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   build:

testdata/cyclic/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   task-1:

testdata/deps/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   default:

testdata/dir/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   whereami:

testdata/dir/explicit_doesnt_exist/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   whereami:

testdata/dir/explicit_exists/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   whereami:

testdata/dry/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   build:

testdata/dry_checksum/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   default:

testdata/env/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 vars:
   BAZ:

testdata/expand/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   pwd:

testdata/generates/Taskfile.yml

@@ -1,4 +1,7 @@
-version: '2'
+version: '3'
+
+vars:
+  BUILD_DIR: $pwd
 
 tasks:
   abs.txt:

testdata/generates/Taskvars.yml

@@ -1 +0,0 @@
-BUILD_DIR: $pwd

testdata/ignore_errors/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   task-should-pass:

testdata/includes_call_root_task/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 includes:
   included: Taskfile2.yml

testdata/includes_call_root_task/Taskfile2.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   call-root:

testdata/includes_deps/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 includes:
   included: Taskfile2.yml

testdata/includes_deps/Taskfile2.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   default:

testdata/includes_empty/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 includes:
   included: Taskfile2.yml

testdata/includes_empty/Taskfile2.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 vars:
   FILE: file.txt

testdata/params/Taskfile.yml

@@ -1,4 +1,8 @@
-version: '2'
+version: '3'
+
+vars:
+  PORTUGUESE_HELLO_WORLD: Olá, mundo!
+  GERMAN: Hello
 
 tasks:
   default:

testdata/params/Taskvars.yml

@@ -1,2 +0,0 @@
-PORTUGUESE_HELLO_WORLD: Olá, mundo!
-GERMAN: "Hello"

testdata/precondition/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   foo:

testdata/status/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   gen-foo:

testdata/summary/Taskfile.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 
 tasks:
   task-with-summary:

testdata/vars/v3/.gitignore

@@ -0,0 +1 @@
+*.txt

testdata/vars/v3/Taskfile.yml

@@ -0,0 +1,46 @@
+version: '3'
+
+vars:
+  VAR_A: A
+  VAR_B: '{{.VAR_A}}B'
+  VAR_C: '{{.VAR_B}}C'
+
+  VAR_1: {sh: echo 1}
+  VAR_2: {sh: 'echo "{{.VAR_1}}2"'}
+  VAR_3: {sh: 'echo "{{.VAR_2}}3"'}
+
+tasks:
+  default:
+    - task: missing-var
+    - task: var-order
+    - task: dependent-sh
+    - task: with-call
+
+  missing-var: echo '{{.NON_EXISTING_VAR}}' > missing-var.txt
+
+  var-order:
+    vars:
+      VAR_D: '{{.VAR_C}}D'
+      VAR_E: '{{.VAR_D}}E'
+      VAR_F: '{{.VAR_E}}F'
+    cmds:
+      - echo '{{.VAR_F}}' > var-order.txt
+
+  dependent-sh:
+    vars:
+      VAR_4: {sh: 'echo "{{.VAR_3}}4"'}
+      VAR_5: {sh: 'echo "{{.VAR_4}}5"'}
+      VAR_6: {sh: 'echo "{{.VAR_5}}6"'}
+    cmds:
+      - echo '{{.VAR_6}}' > dependent-sh.txt
+
+  with-call:
+    - task: called-task
+      vars:
+        ABC123: '{{.VAR_C}}{{.VAR_3}}'
+
+  called-task:
+    vars:
+      MESSAGE: Hi, {{.ABC123}}!
+    cmds:
+      - echo "{{.MESSAGE}}" > with-call.txt

variables.go

@@ -23,7 +23,12 @@ func (e *Executor) CompiledTask(call taskfile.Call) (*taskfile.Task, error) {
 		return nil, err
 	}
 
-	r := templater.Templater{Vars: vars}
+	v, err := e.parsedVersion()
+	if err != nil {
+		return nil, err
+	}
+
+	r := templater.Templater{Vars: vars, RemoveNoValue: v >= 3.0}
 
 	new := taskfile.Task{
 		Task:        origTask.Task,
@@ -50,19 +55,19 @@ func (e *Executor) CompiledTask(call taskfile.Call) (*taskfile.Task, error) {
 		new.Prefix = new.Task
 	}
 
-	new.Env = make(taskfile.Vars, len(e.Taskfile.Env)+len(origTask.Env))
-	for k, v := range r.ReplaceVars(e.Taskfile.Env) {
-		new.Env[k] = v
-	}
-	for k, v := range r.ReplaceVars(origTask.Env) {
-		new.Env[k] = v
-	}
-	for k, v := range new.Env {
+	new.Env = &taskfile.Vars{}
+	new.Env.Merge(r.ReplaceVars(e.Taskfile.Env))
+	new.Env.Merge(r.ReplaceVars(origTask.Env))
+	err = new.Env.Range(func(k string, v taskfile.Var) error {
 		static, err := e.Compiler.HandleDynamicVar(v)
 		if err != nil {
-			return nil, err
+			return err
 		}
-		new.Env[k] = taskfile.Var{Static: static}
+		new.Env.Set(k, taskfile.Var{Static: static})
+		return nil
+	})
+	if err != nil {
+		return nil, err
 	}
 
 	if len(origTask.Cmds) > 0 {
@@ -103,7 +108,7 @@ func (e *Executor) CompiledTask(call taskfile.Call) (*taskfile.Task, error) {
 			if err != nil {
 				return nil, err
 			}
-			vars[strings.ToUpper(checker.Kind())] = taskfile.Var{Live: value}
+			vars.Set(strings.ToUpper(checker.Kind()), taskfile.Var{Live: value})
 		}
 
 		// Adding new variables, requires us to refresh the templaters