v2.6.0

Ref: https://github.com/go-task/homebrew-tap/pull/1

Thanks @dawidd6

.github/FUNDING.yml

@@ -0,0 +1 @@
+open_collective: task

.gitignore

@@ -21,3 +21,6 @@ dist/
 
 # intellij idea/goland
 .idea/
+
+# exuberant ctags
+tags

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Changelog
 
+## Unreleased
+
+- Fixed some bugs regarding minor version checks on `version:`.
+- Add `preconditions:` to task
+  ([#205](https://github.com/go-task/task/pull/205)).
+- Create directory informed on `dir:` if it doesn't exist
+  ([#209](https://github.com/go-task/task/issues/209), [#211](https://github.com/go-task/task/pull/211)).
+- We now have a `--taskfile` flag (alias `-t`), which can be used to run
+  another Taskfile (other than the default `Taskfile.yml`)
+  ([#221](https://github.com/go-task/task/pull/221)).
+- It's now possible to install Task using Homebrew on Linux
+  ([go-task/homebrew-tap#1](https://github.com/go-task/homebrew-tap/pull/1)).
+
 ## v2.5.2 - 2019-05-11
 
 - Reverted YAML upgrade due issues with CRLF on Windows

cmd/task/task.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"syscall"
 
 	"github.com/go-task/task/v2"
@@ -17,7 +18,7 @@ var (
 	version = "master"
 )
 
-const usage = `Usage: task [-ilfwvsd] [--init] [--list] [--force] [--watch] [--verbose] [--silent] [--dir] [--dry] [--summary] [task...]
+const usage = `Usage: task [-ilfwvsd] [--init] [--list] [--force] [--watch] [--verbose] [--silent] [--dir] [--taskfile] [--dry] [--summary] [task...]
 
 Runs the specified task(s). Falls back to the "default" task if no task name
 was specified, or lists all tasks if an unknown task name was specified.
@@ -58,6 +59,7 @@ func main() {
 		dry         bool
 		summary     bool
 		dir         string
+		entrypoint  string
 		output      string
 	)
 
@@ -72,6 +74,7 @@ func main() {
 	pflag.BoolVar(&dry, "dry", false, "compiles and prints tasks in the order that they would be run, without executing them")
 	pflag.BoolVar(&summary, "summary", false, "show summary about a task")
 	pflag.StringVarP(&dir, "dir", "d", "", "sets directory of execution")
+	pflag.StringVarP(&entrypoint, "taskfile", "t", "", `choose which Taskfile to run. Defaults to "Taskfile.yml"`)
 	pflag.StringVarP(&output, "output", "o", "", "sets output style: [interleaved|group|prefixed]")
 	pflag.Parse()
 
@@ -91,14 +94,26 @@ func main() {
 		return
 	}
 
+	if dir != "" && entrypoint != "" {
+		log.Fatal("task: You can't set both --dir and --taskfile")
+		return
+	}
+	if entrypoint != "" {
+		dir = filepath.Dir(entrypoint)
+		entrypoint = filepath.Base(entrypoint)
+	} else {
+		entrypoint = "Taskfile.yml"
+	}
+
 	e := task.Executor{
-		Force:   force,
-		Watch:   watch,
-		Verbose: verbose,
-		Silent:  silent,
-		Dir:     dir,
-		Dry:     dry,
-		Summary: summary,
+		Force:      force,
+		Watch:      watch,
+		Verbose:    verbose,
+		Silent:     silent,
+		Dir:        dir,
+		Dry:        dry,
+		Entrypoint: entrypoint,
+		Summary:    summary,
 
 		Stdin:  os.Stdin,
 		Stdout: os.Stdout,

docs/installation.md

@@ -8,13 +8,15 @@ The `task_checksums.txt` file contains the sha256 checksum for each file.
 
 ## Homebrew
 
-If you're on macOS and have [Homebrew][homebrew] installed, getting Task is
-as simple as running:
+If you're on macOS or Linux and have [Homebrew][homebrew] installed, getting
+Task is as simple as running:
 
 ```bash
 brew install go-task/tap/go-task
 ```
 
+> This installation method is only currently supported on amd64 architectures.
+
 ## Snap
 
 Task is available for [Snapcraft][snapcraft], but keep in mind that your

docs/taskfile_versions.md

@@ -141,6 +141,21 @@ includes:
   docker: ./DockerTasks.yml
 ```
 
+## Version 2.6
+
+Version 2.6 comes with `preconditions` stanza in tasks.
+
+```yaml
+version: '2'
+
+tasks:
+  upload_environment:
+    preconditions:
+      - test -f .env
+    cmds:
+      - aws s3 cp .env s3://myenvironment
+```
+
 Please check the [documentation][includes]
 
 [output]: usage.md#output-syntax

docs/usage.md

@@ -148,6 +148,8 @@ tasks:
       - caddy
 ```
 
+If the directory doesn't exist, `task` creates it.
+
 ## Task dependencies
 
 You may have tasks that depend on others. Just pointing them on `deps` will
@@ -344,6 +346,55 @@ up-to-date.
 Also, `task --status [tasks]...` will exit with a non-zero exit code if any of
 the tasks are not up-to-date.
 
+If you need a certain set of conditions to be _true_ you can use the
+`preconditions` stanza.  `preconditions` are very similar to `status`
+lines except they support `sh` expansion and they SHOULD all return 0.
+
+```yaml
+version: '2'
+
+tasks:
+  generate-files:
+    cmds:
+      - mkdir directory
+      - touch directory/file1.txt
+      - touch directory/file2.txt
+    # test existence of files
+    preconditions:
+      - test -f .env
+      - sh: "[ 1 = 0 ]"
+        msg: "One doesn't equal Zero, Halting"
+```
+
+Preconditions can set specific failure messages that can tell
+a user what steps to take using the `msg` field.
+
+If a task has a dependency on a sub-task with a precondition, and that
+precondition is not met - the calling task will fail.  Note that a task
+executed with a failing precondition will not run unless `--force` is
+given.
+
+Unlike `status` which will skip a task if it is up to date, and continue
+executing tasks that depend on it, a `precondition` will fail a task, along
+with any other tasks that depend on it.
+
+```yaml
+version: '2'
+tasks:
+  task_will_fail:
+    preconditions:
+      - sh: "exit 1"
+
+  task_will_also_fail:
+    deps:
+      - task_will_fail
+
+  task_will_still_fail:
+    cmds:
+      - task: task_will_fail
+      - echo "I will not run"
+```
+
 ## Variables
 
 When doing interpolation of variables, Task will look for the below.
@@ -385,7 +436,7 @@ version: '2'
 tasks:
   print-var:
     cmds:
-      echo "{{.VAR}}"
+      - echo "{{.VAR}}"
     vars:
       VAR: Hello!
 ```

go.mod

@@ -1,7 +1,7 @@
 module github.com/go-task/task/v2
 
 require (
-	github.com/Masterminds/semver v1.4.2
+	github.com/Masterminds/semver v1.4.2 // indirect
 	github.com/Masterminds/sprig v2.16.0+incompatible
 	github.com/aokoli/goutils v1.0.1 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect

internal/taskfile/precondition.go

@@ -0,0 +1,45 @@
+package taskfile
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	// ErrCantUnmarshalPrecondition is returned for invalid precond YAML.
+	ErrCantUnmarshalPrecondition = errors.New("task: Can't unmarshal precondition value")
+)
+
+// Precondition represents a precondition necessary for a task to run
+type Precondition struct {
+	Sh  string
+	Msg string
+}
+
+// UnmarshalYAML implements yaml.Unmarshaler interface.
+func (p *Precondition) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	var cmd string
+
+	if err := unmarshal(&cmd); err == nil {
+		p.Sh = cmd
+		p.Msg = fmt.Sprintf("`%s` failed", cmd)
+		return nil
+	}
+
+	var sh struct {
+		Sh  string
+		Msg string
+	}
+
+	if err := unmarshal(&sh); err != nil {
+		return err
+	}
+
+	p.Sh = sh.Sh
+	p.Msg = sh.Msg
+	if p.Msg == "" {
+		p.Msg = fmt.Sprintf("%s failed", sh.Sh)
+	}
+
+	return nil
+}

internal/taskfile/precondition_test.go

@@ -0,0 +1,48 @@
+package taskfile_test
+
+import (
+	"testing"
+
+	"github.com/go-task/task/v2/internal/taskfile"
+
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v2"
+)
+
+func TestPreconditionParse(t *testing.T) {
+	tests := []struct {
+		content  string
+		v        interface{}
+		expected interface{}
+	}{
+		{
+			"test -f foo.txt",
+			&taskfile.Precondition{},
+			&taskfile.Precondition{Sh: `test -f foo.txt`, Msg: "`test -f foo.txt` failed"},
+		},
+		{
+			"sh: '[ 1 = 0 ]'",
+			&taskfile.Precondition{},
+			&taskfile.Precondition{Sh: "[ 1 = 0 ]", Msg: "[ 1 = 0 ] failed"},
+		},
+		{`
+sh: "[ 1 = 2 ]"
+msg: "1 is not 2"
+`,
+			&taskfile.Precondition{},
+			&taskfile.Precondition{Sh: "[ 1 = 2 ]", Msg: "1 is not 2"},
+		},
+		{`
+sh: "[ 1 = 2 ]"
+msg: "1 is not 2"
+`,
+			&taskfile.Precondition{},
+			&taskfile.Precondition{Sh: "[ 1 = 2 ]", Msg: "1 is not 2"},
+		},
+	}
+	for _, test := range tests {
+		err := yaml.Unmarshal([]byte(test.content), test.v)
+		assert.NoError(t, err)
+		assert.Equal(t, test.expected, test.v)
+	}
+}

internal/taskfile/read/taskfile.go

@@ -15,16 +15,13 @@ import (
 var (
 	// ErrIncludedTaskfilesCantHaveIncludes is returned when a included Taskfile contains includes
 	ErrIncludedTaskfilesCantHaveIncludes = errors.New("task: Included Taskfiles can't have includes. Please, move the include to the main Taskfile")
-
-	// ErrNoTaskfileFound is returned when Taskfile.yml is not found
-	ErrNoTaskfileFound = errors.New(`task: No Taskfile.yml found. Use "task --init" to create a new one`)
 )
 
 // Taskfile reads a Taskfile for a given directory
-func Taskfile(dir string) (*taskfile.Taskfile, error) {
-	path := filepath.Join(dir, "Taskfile.yml")
+func Taskfile(dir string, entrypoint string) (*taskfile.Taskfile, error) {
+	path := filepath.Join(dir, entrypoint)
 	if _, err := os.Stat(path); err != nil {
-		return nil, ErrNoTaskfileFound
+		return nil, fmt.Errorf(`task: No Taskfile found on "%s". Use "task --init" to create a new one`, path)
 	}
 	t, err := readTaskfile(path)
 	if err != nil {

internal/taskfile/task.go

@@ -5,19 +5,20 @@ type Tasks map[string]*Task
 
 // Task represents a task
 type Task struct {
-	Task        string
-	Cmds        []*Cmd
-	Deps        []*Dep
-	Desc        string
-	Summary     string
-	Sources     []string
-	Generates   []string
-	Status      []string
-	Dir         string
-	Vars        Vars
-	Env         Vars
-	Silent      bool
-	Method      string
-	Prefix      string
-	IgnoreError bool `yaml:"ignore_error"`
+	Task         string
+	Cmds         []*Cmd
+	Deps         []*Dep
+	Desc         string
+	Summary      string
+	Sources      []string
+	Generates    []string
+	Status       []string
+	Preconditions []*Precondition
+	Dir          string
+	Vars         Vars
+	Env          Vars
+	Silent       bool
+	Method       string
+	Prefix       string
+	IgnoreError  bool `yaml:"ignore_error"`
 }

internal/taskfile/version/version.go

@@ -1,46 +0,0 @@
-package version
-
-import (
-	"github.com/Masterminds/semver"
-)
-
-var (
-	v1  = mustVersion("1")
-	v2  = mustVersion("2")
-	v21 = mustVersion("2.1")
-	v22 = mustVersion("2.2")
-	v23 = mustVersion("2.3")
-)
-
-// IsV1 returns if is a given Taskfile version is version 1
-func IsV1(v *semver.Constraints) bool {
-	return v.Check(v1)
-}
-
-// IsV2 returns if is a given Taskfile version is at least version 2
-func IsV2(v *semver.Constraints) bool {
-	return v.Check(v2)
-}
-
-// IsV21 returns if is a given Taskfile version is at least version 2.1
-func IsV21(v *semver.Constraints) bool {
-	return v.Check(v21)
-}
-
-// IsV22 returns if is a given Taskfile version is at least version 2.2
-func IsV22(v *semver.Constraints) bool {
-	return v.Check(v22)
-}
-
-// IsV23 returns if is a given Taskfile version is at least version 2.3
-func IsV23(v *semver.Constraints) bool {
-	return v.Check(v23)
-}
-
-func mustVersion(s string) *semver.Version {
-	v, err := semver.NewVersion(s)
-	if err != nil {
-		panic(err)
-	}
-	return v
-}

precondition.go

@@ -0,0 +1,31 @@
+package task
+
+import (
+	"context"
+	"errors"
+
+	"github.com/go-task/task/v2/internal/execext"
+	"github.com/go-task/task/v2/internal/taskfile"
+)
+
+var (
+	// ErrPreconditionFailed is returned when a precondition fails
+	ErrPreconditionFailed = errors.New("task: precondition not met")
+)
+
+func (e *Executor) areTaskPreconditionsMet(ctx context.Context, t *taskfile.Task) (bool, error) {
+	for _, p := range t.Preconditions {
+		err := execext.RunCommand(ctx, &execext.RunCommandOptions{
+			Command: p.Sh,
+			Dir:     t.Dir,
+			Env:     getEnviron(t),
+		})
+
+		if err != nil {
+			e.Logger.Errf("task: %s", p.Msg)
+			return false, ErrPreconditionFailed
+		}
+	}
+
+	return true, nil
+}

status.go

@@ -78,8 +78,10 @@ func (e *Executor) isTaskUpToDateStatus(ctx context.Context, t *taskfile.Task) (
 			Env:     getEnviron(t),
 		})
 		if err != nil {
+			e.Logger.VerboseOutf("task: status command %s exited non-zero: %s", s, err)
 			return false, nil
 		}
+		e.Logger.VerboseOutf("task: status command %s exited zero", s)
 	}
 	return true, nil
 }

task.go

@@ -2,9 +2,12 @@ package task
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
+	"strconv"
+	"sync"
 	"sync/atomic"
 
 	"github.com/go-task/task/v2/internal/compiler"
@@ -16,9 +19,7 @@ import (
 	"github.com/go-task/task/v2/internal/summary"
 	"github.com/go-task/task/v2/internal/taskfile"
 	"github.com/go-task/task/v2/internal/taskfile/read"
-	"github.com/go-task/task/v2/internal/taskfile/version"
 
-	"github.com/Masterminds/semver"
 	"golang.org/x/sync/errgroup"
 )
 
@@ -31,13 +32,15 @@ const (
 // Executor executes a Taskfile
 type Executor struct {
 	Taskfile *taskfile.Taskfile
-	Dir      string
-	Force    bool
-	Watch    bool
-	Verbose  bool
-	Silent   bool
-	Dry      bool
-	Summary  bool
+
+	Dir        string
+	Entrypoint string
+	Force      bool
+	Watch      bool
+	Verbose    bool
+	Silent     bool
+	Dry        bool
+	Summary    bool
 
 	Stdin  io.Reader
 	Stdout io.Writer
@@ -51,6 +54,7 @@ type Executor struct {
 	taskvars taskfile.Vars
 
 	taskCallCount map[string]*int32
+	mkdirMutexMap map[string]*sync.Mutex
 }
 
 // Run runs Task
@@ -83,8 +87,12 @@ func (e *Executor) Run(ctx context.Context, calls ...taskfile.Call) error {
 
 // Setup setups Executor's internal state
 func (e *Executor) Setup() error {
+	if e.Entrypoint == "" {
+		e.Entrypoint = "Taskfile.yml"
+	}
+
 	var err error
-	e.Taskfile, err = read.Taskfile(e.Dir)
+	e.Taskfile, err = read.Taskfile(e.Dir, e.Entrypoint)
 	if err != nil {
 		return err
 	}
@@ -93,11 +101,6 @@ func (e *Executor) Setup() error {
 		return err
 	}
 
-	v, err := semver.NewConstraint(e.Taskfile.Version)
-	if err != nil {
-		return fmt.Errorf(`task: could not parse taskfile version "%s": %v`, e.Taskfile.Version, err)
-	}
-
 	if e.Stdin == nil {
 		e.Stdin = os.Stdin
 	}
@@ -112,14 +115,30 @@ func (e *Executor) Setup() error {
 		Stderr:  e.Stderr,
 		Verbose: e.Verbose,
 	}
-	switch {
-	case version.IsV1(v):
+
+	v, err := strconv.ParseFloat(e.Taskfile.Version, 64)
+	if err != nil {
+		return fmt.Errorf(`task: Could not parse taskfile version "%s": %v`, e.Taskfile.Version, err)
+	}
+	// consider as equal to the greater version if round
+	if v == 2.0 {
+		v = 2.6
+	}
+
+	if v < 1 {
+		return fmt.Errorf(`task: Taskfile version should be greater or equal to v1`)
+	}
+	if v > 2.6 {
+		return fmt.Errorf(`task: Taskfile versions greater than v2.6 not implemented in the version of Task`)
+	}
+
+	if v < 2 {
 		e.Compiler = &compilerv1.CompilerV1{
 			Dir:    e.Dir,
 			Vars:   e.taskvars,
 			Logger: e.Logger,
 		}
-	case version.IsV2(v), version.IsV21(v), version.IsV22(v):
+	} else { // v >= 2
 		e.Compiler = &compilerv2.CompilerV2{
 			Dir:          e.Dir,
 			Taskvars:     e.taskvars,
@@ -127,16 +146,15 @@ func (e *Executor) Setup() error {
 			Expansions:   e.Taskfile.Expansions,
 			Logger:       e.Logger,
 		}
-	case version.IsV23(v):
-		return fmt.Errorf(`task: Taskfile versions greater than v2.3 not implemented in the version of Task`)
 	}
 
-	if !version.IsV21(v) && e.Taskfile.Output != "" {
+	if v < 2.1 && e.Taskfile.Output != "" {
 		return fmt.Errorf(`task: Taskfile option "output" is only available starting on Taskfile version v2.1`)
 	}
-	if !version.IsV22(v) && len(e.Taskfile.Includes) > 0 {
+	if v < 2.2 && len(e.Taskfile.Includes) > 0 {
 		return fmt.Errorf(`task: Including Taskfiles is only available starting on Taskfile version v2.2`)
 	}
+
 	if e.OutputStyle != "" {
 		e.Taskfile.Output = e.OutputStyle
 	}
@@ -151,8 +169,8 @@ func (e *Executor) Setup() error {
 		return fmt.Errorf(`task: output option "%s" not recognized`, e.Taskfile.Output)
 	}
 
-	if !version.IsV21(v) {
-		err := fmt.Errorf(`task: Taskfile option "ignore_error" is only available starting on Taskfile version v2.1`)
+	if v <= 2.1 {
+		err := errors.New(`task: Taskfile option "ignore_error" is only available starting on Taskfile version v2.1`)
 
 		for _, task := range e.Taskfile.Tasks {
 			if task.IgnoreError {
@@ -166,9 +184,19 @@ func (e *Executor) Setup() error {
 		}
 	}
 
+	if v < 2.6 {
+		for _, task := range e.Taskfile.Tasks {
+			if len(task.Preconditions) > 0 {
+				return errors.New(`task: Task option "preconditions" is only available starting on Taskfile version v2.6`)
+			}
+		}
+	}
+
 	e.taskCallCount = make(map[string]*int32, len(e.Taskfile.Tasks))
+	e.mkdirMutexMap = make(map[string]*sync.Mutex, len(e.Taskfile.Tasks))
 	for k := range e.Taskfile.Tasks {
 		e.taskCallCount[k] = new(int32)
+		e.mkdirMutexMap[k] = &sync.Mutex{}
 	}
 	return nil
 }
@@ -188,11 +216,17 @@ func (e *Executor) RunTask(ctx context.Context, call taskfile.Call) error {
 	}
 
 	if !e.Force {
+		preCondMet, err := e.areTaskPreconditionsMet(ctx, t)
+		if err != nil {
+			return err
+		}
+
 		upToDate, err := e.isTaskUpToDate(ctx, t)
 		if err != nil {
 			return err
 		}
-		if upToDate {
+
+		if upToDate && preCondMet {
 			if !e.Silent {
 				e.Logger.Errf(`task: Task "%s" is up to date`, t.Task)
 			}
@@ -200,6 +234,10 @@ func (e *Executor) RunTask(ctx context.Context, call taskfile.Call) error {
 		}
 	}
 
+	if err := e.mkdir(t); err != nil {
+		e.Logger.Errf("task: cannot make directory %q: %v", t.Dir, err)
+	}
+
 	for i := range t.Cmds {
 		if err := e.runCommand(ctx, t, call, i); err != nil {
 			if err2 := e.statusOnError(t); err2 != nil {
@@ -217,6 +255,23 @@ func (e *Executor) RunTask(ctx context.Context, call taskfile.Call) error {
 	return nil
 }
 
+func (e *Executor) mkdir(t *taskfile.Task) error {
+	if t.Dir == "" {
+		return nil
+	}
+
+	mutex := e.mkdirMutexMap[t.Task]
+	mutex.Lock()
+	defer mutex.Unlock()
+
+	if _, err := os.Stat(t.Dir); os.IsNotExist(err) {
+		if err := os.MkdirAll(t.Dir, 0755); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (e *Executor) runDeps(ctx context.Context, t *taskfile.Task) error {
 	g, ctx := errgroup.WithContext(ctx)
 
@@ -224,7 +279,11 @@ func (e *Executor) runDeps(ctx context.Context, t *taskfile.Task) error {
 		d := d
 
 		g.Go(func() error {
-			return e.RunTask(ctx, taskfile.Call{Task: d.Task, Vars: d.Vars})
+			err := e.RunTask(ctx, taskfile.Call{Task: d.Task, Vars: d.Vars})
+			if err != nil {
+				return err
+			}
+			return nil
 		})
 	}
 
@@ -236,7 +295,11 @@ func (e *Executor) runCommand(ctx context.Context, t *taskfile.Task, call taskfi
 
 	switch {
 	case cmd.Task != "":
-		return e.RunTask(ctx, taskfile.Call{Task: cmd.Task, Vars: cmd.Vars})
+		err := e.RunTask(ctx, taskfile.Call{Task: cmd.Task, Vars: cmd.Vars})
+		if err != nil {
+			return err
+		}
+		return nil
 	case cmd.Cmd != "":
 		if e.Verbose || (!cmd.Silent && !t.Silent && !e.Silent) {
 			e.Logger.Errf(cmd.Cmd)

task_test.go

@@ -236,7 +236,7 @@ func TestDeps(t *testing.T) {
 	for _, f := range files {
 		f = filepath.Join(dir, f)
 		if _, err := os.Stat(f); err != nil {
-			t.Errorf("File %s should exists", f)
+			t.Errorf("File %s should exist", f)
 		}
 	}
 }
@@ -248,7 +248,7 @@ func TestStatus(t *testing.T) {
 	_ = os.Remove(file)
 
 	if _, err := os.Stat(file); err == nil {
-		t.Errorf("File should not exists: %v", err)
+		t.Errorf("File should not exist: %v", err)
 	}
 
 	var buff bytes.Buffer
@@ -262,7 +262,7 @@ func TestStatus(t *testing.T) {
 	assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: "gen-foo"}))
 
 	if _, err := os.Stat(file); err != nil {
-		t.Errorf("File should exists: %v", err)
+		t.Errorf("File should exist: %v", err)
 	}
 
 	e.Silent = false
@@ -273,6 +273,47 @@ func TestStatus(t *testing.T) {
 	}
 }
 
+func TestPrecondition(t *testing.T) {
+	const dir = "testdata/precondition"
+
+	var buff bytes.Buffer
+	e := &task.Executor{
+		Dir:    dir,
+		Stdout: &buff,
+		Stderr: &buff,
+	}
+
+	// A precondition that has been met
+	assert.NoError(t, e.Setup())
+	assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: "foo"}))
+	if buff.String() != "" {
+		t.Errorf("Got Output when none was expected: %s", buff.String())
+	}
+
+	// A precondition that was not met
+	assert.Error(t, e.Run(context.Background(), taskfile.Call{Task: "impossible"}))
+
+	if buff.String() != "task: 1 != 0 obviously!\n" {
+		t.Errorf("Wrong output message: %s", buff.String())
+	}
+	buff.Reset()
+
+	// Calling a task with a precondition in a dependency fails the task
+	assert.Error(t, e.Run(context.Background(), taskfile.Call{Task: "depends_on_impossible"}))
+
+	if buff.String() != "task: 1 != 0 obviously!\n" {
+		t.Errorf("Wrong output message: %s", buff.String())
+	}
+	buff.Reset()
+
+	// Calling a task with a precondition in a cmd fails the task
+	assert.Error(t, e.Run(context.Background(), taskfile.Call{Task: "executes_failing_task_as_cmd"}))
+	if buff.String() != "task: 1 != 0 obviously!\n" {
+		t.Errorf("Wrong output message: %s", buff.String())
+	}
+	buff.Reset()
+}
+
 func TestGenerates(t *testing.T) {
 	const (
 		srcTask        = "sub/src.txt"
@@ -290,7 +331,7 @@ func TestGenerates(t *testing.T) {
 		path := filepath.Join(dir, task)
 		_ = os.Remove(path)
 		if _, err := os.Stat(path); err == nil {
-			t.Errorf("File should not exists: %v", err)
+			t.Errorf("File should not exist: %v", err)
 		}
 	}
 
@@ -311,10 +352,10 @@ func TestGenerates(t *testing.T) {
 		assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: theTask}))
 
 		if _, err := os.Stat(srcFile); err != nil {
-			t.Errorf("File should exists: %v", err)
+			t.Errorf("File should exist: %v", err)
 		}
 		if _, err := os.Stat(destFile); err != nil {
-			t.Errorf("File should exists: %v", err)
+			t.Errorf("File should exist: %v", err)
 		}
 		// Ensure task was not incorrectly found to be up-to-date on first run.
 		if buff.String() == upToDate {
@@ -371,7 +412,7 @@ func TestInit(t *testing.T) {
 
 	_ = os.Remove(file)
 	if _, err := os.Stat(file); err == nil {
-		t.Errorf("Taskfile.yml should not exists")
+		t.Errorf("Taskfile.yml should not exist")
 	}
 
 	if err := task.InitTaskfile(ioutil.Discard, dir); err != nil {
@@ -379,7 +420,7 @@ func TestInit(t *testing.T) {
 	}
 
 	if _, err := os.Stat(file); err != nil {
-		t.Errorf("Taskfile.yml should exists")
+		t.Errorf("Taskfile.yml should exist")
 	}
 }
 
@@ -575,3 +616,65 @@ func readTestFixture(t *testing.T, dir string, file string) string {
 	assert.NoError(t, err, "error reading text fixture")
 	return string(b)
 }
+
+func TestWhenNoDirAttributeItRunsInSameDirAsTaskfile(t *testing.T) {
+	const expected = "dir"
+	const dir = "testdata/" + expected
+	var out bytes.Buffer
+	e := &task.Executor{
+		Dir:    dir,
+		Stdout: &out,
+		Stderr: &out,
+	}
+
+	assert.NoError(t, e.Setup())
+	assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: "whereami"}))
+
+	// got should be the "dir" part of "testdata/dir"
+	got := strings.TrimSuffix(filepath.Base(out.String()), "\n")
+	assert.Equal(t, expected, got, "Mismatch in the working directory")
+}
+
+func TestWhenDirAttributeAndDirExistsItRunsInThatDir(t *testing.T) {
+	const expected = "exists"
+	const dir = "testdata/dir/explicit_exists"
+	var out bytes.Buffer
+	e := &task.Executor{
+		Dir:    dir,
+		Stdout: &out,
+		Stderr: &out,
+	}
+
+	assert.NoError(t, e.Setup())
+	assert.NoError(t, e.Run(context.Background(), taskfile.Call{Task: "whereami"}))
+
+	got := strings.TrimSuffix(filepath.Base(out.String()), "\n")
+	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/Taskfile.yml

@@ -0,0 +1,7 @@
+version: '2'
+
+tasks:
+  whereami:
+    cmds:
+      - pwd
+    silent: true

testdata/dir/explicit_doesnt_exist/Taskfile.yml

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

testdata/dir/explicit_exists/Taskfile.yml

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

testdata/precondition/Taskfile.yml

@@ -0,0 +1,19 @@
+version: '2'
+
+tasks:
+  foo:
+    preconditions:
+      - test -f foo.txt
+
+  impossible:
+    preconditions:
+      - sh: "[ 1 = 0 ]"
+        msg: "1 != 0 obviously!"
+
+  depends_on_impossible:
+    deps:
+      - impossible
+
+  executes_failing_task_as_cmd:
+    cmds:
+      - task: impossible

variables.go

@@ -84,5 +84,15 @@ func (e *Executor) CompiledTask(call taskfile.Call) (*taskfile.Task, error) {
 		}
 	}
 
+	if len(origTask.Preconditions) > 0 {
+		new.Preconditions = make([]*taskfile.Precondition, len(origTask.Preconditions))
+		for i, precond := range origTask.Preconditions {
+			new.Preconditions[i] = &taskfile.Precondition{
+				Sh:  r.Replace(precond.Sh),
+				Msg: r.Replace(precond.Msg),
+			}
+		}
+	}
+
 	return &new, r.Err()
 }