feat: added variable override flag --var

compiler.go

@@ -33,18 +33,18 @@ type Compiler struct {
 }
 
 func (c *Compiler) GetTaskfileVariables() (*ast.Vars, error) {
-	return c.getVariables(nil, nil, true)
+	return c.getVariables(nil, nil, true, map[string]string{})
 }
 
 func (c *Compiler) GetVariables(t *ast.Task, call *Call) (*ast.Vars, error) {
-	return c.getVariables(t, call, true)
+	return c.getVariables(t, call, true, map[string]string{})
 }
 
-func (c *Compiler) FastGetVariables(t *ast.Task, call *Call) (*ast.Vars, error) {
-	return c.getVariables(t, call, false)
+func (c *Compiler) FastGetVariables(t *ast.Task, call *Call, overrideVars map[string]string) (*ast.Vars, error) {
+	return c.getVariables(t, call, false, overrideVars)
 }
 
-func (c *Compiler) getVariables(t *ast.Task, call *Call, evaluateShVars bool) (*ast.Vars, error) {
+func (c *Compiler) getVariables(t *ast.Task, call *Call, evaluateShVars bool, overrideVars map[string]string) (*ast.Vars, error) {
 	result := env.GetEnviron()
 	specialVars, err := c.getSpecialVars(t, call)
 	if err != nil {
@@ -56,6 +56,12 @@ func (c *Compiler) getVariables(t *ast.Task, call *Call, evaluateShVars bool) (*
 
 	getRangeFunc := func(dir string) func(k string, v ast.Var) error {
 		return func(k string, v ast.Var) error {
+			val, ok := overrideVars[k]
+
+			if ok {
+				v = ast.Var{Value: val}
+			}
+
 			cache := &templater.Cache{Vars: result}
 			// Replace values
 			newVar := templater.ReplaceVar(v, cache)

executor.go

@@ -38,6 +38,7 @@ type (
 		CacheExpiryDuration time.Duration
 		Watch               bool
 		Verbose             bool
+		Vars                map[string]string
 		Silent              bool
 		AssumeYes           bool
 		AssumeTerm          bool // Used for testing
@@ -274,14 +275,26 @@ func WithVerbose(verbose bool) ExecutorOption {
 	return &verboseOption{verbose}
 }
 
+func WithVars(vars map[string]string) ExecutorOption {
+	return &varsOption{vars}
+}
+
 type verboseOption struct {
 	verbose bool
 }
 
+type varsOption struct {
+	vars map[string]string
+}
+
 func (o *verboseOption) ApplyToExecutor(e *Executor) {
 	e.Verbose = o.verbose
 }
 
+func (o *varsOption) ApplyToExecutor(e *Executor) {
+	e.Vars = o.vars
+}
+
 // WithSilent tells the [Executor] to suppress all output except for the output
 // of the tasks that are run.
 func WithSilent(silent bool) ExecutorOption {

executor_test.go

@@ -265,6 +265,17 @@ func TestVars(t *testing.T) {
 	)
 }
 
+func TestVarOverride(t *testing.T) {
+	t.Parallel()
+	NewExecutorTest(t,
+		WithExecutorOptions(
+			task.WithDir("testdata/var_override"),
+			task.WithSilent(true),
+			task.WithVars(map[string]string{"MYVAR": "bar"}),
+		),
+	)
+}
+
 func TestRequires(t *testing.T) {
 	t.Parallel()
 	NewExecutorTest(t,

internal/flags/flags.go

@@ -56,6 +56,7 @@ var (
 	ForceAll            bool
 	Watch               bool
 	Verbose             bool
+	Vars                map[string]string
 	Silent              bool
 	AssumeYes           bool
 	Dry                 bool
@@ -121,6 +122,7 @@ func init() {
 	pflag.BoolVar(&Insecure, "insecure", false, "Forces Task to download Taskfiles over insecure connections.")
 	pflag.BoolVarP(&Watch, "watch", "w", false, "Enables watch of the given task.")
 	pflag.BoolVarP(&Verbose, "verbose", "v", false, "Enables verbose mode.")
+	pflag.StringToStringVarP(&Vars, "var", "V", map[string]string{}, "Provide variable overrides")
 	pflag.BoolVarP(&Silent, "silent", "s", false, "Disables echoing.")
 	pflag.BoolVarP(&AssumeYes, "yes", "y", false, "Assume \"yes\" as answer to all prompts.")
 	pflag.BoolVarP(&Parallel, "parallel", "p", false, "Executes tasks provided on command line in parallel.")
@@ -238,6 +240,7 @@ func (o *flagsOption) ApplyToExecutor(e *task.Executor) {
 		task.WithCacheExpiryDuration(CacheExpiryDuration),
 		task.WithWatch(Watch),
 		task.WithVerbose(Verbose),
+		task.WithVars(Vars),
 		task.WithSilent(Silent),
 		task.WithAssumeYes(AssumeYes),
 		task.WithDry(Dry || Status),

task.go

@@ -336,7 +336,7 @@ func (e *Executor) runCommand(ctx context.Context, t *ast.Task, call *Call, i in
 		if t.Interactive {
 			outputWrapper = output.Interleaved{}
 		}
-		vars, err := e.Compiler.FastGetVariables(t, call)
+		vars, err := e.Compiler.FastGetVariables(t, call, map[string]string{})
 		outputTemplater := &templater.Cache{Vars: vars}
 		if err != nil {
 			return fmt.Errorf("task: failed to get variables: %w", err)

testdata/var_override/Taskfile.yml

@@ -0,0 +1,9 @@
+version: '3'
+
+vars:
+  MYVAR: foo
+
+tasks:
+  default:
+    cmds:
+      - echo "{{.MYVAR}}"

testdata/var_override/testdata/TestVarOverride.golden

@@ -0,0 +1 @@
+bar

variables.go

@@ -37,9 +37,9 @@ func (e *Executor) compiledTask(call *Call, evaluateShVars bool) (*ast.Task, err
 
 	var vars *ast.Vars
 	if evaluateShVars {
-		vars, err = e.Compiler.GetVariables(origTask, call)
+		vars, err = e.Compiler.getVariables(origTask, call, true, e.Vars)
 	} else {
-		vars, err = e.Compiler.FastGetVariables(origTask, call)
+		vars, err = e.Compiler.FastGetVariables(origTask, call, e.Vars)
 	}
 	if err != nil {
 		return nil, err

website/src/docs/reference/cli.md

@@ -95,6 +95,14 @@ Disable command echoing.
 task deploy --silent
 ```
 
+#### `-V, --var <key>=<value>`
+
+Provide variable overrides to override variables defined in the Taskfile.
+
+```bash
+task build --var FOO=bar
+```
+
 ### Execution Control
 
 #### `-f, --force`