feat(vars): add interactive prompting for required variables (#2579)

requires.go

@@ -4,35 +4,180 @@ import (
 	"slices"
 
 	"github.com/go-task/task/v3/errors"
+	"github.com/go-task/task/v3/internal/input"
+	"github.com/go-task/task/v3/internal/term"
 	"github.com/go-task/task/v3/taskfile/ast"
 )
 
-func (e *Executor) areTaskRequiredVarsSet(t *ast.Task) error {
-	if t.Requires == nil || len(t.Requires.Vars) == 0 {
+func (e *Executor) canPrompt() bool {
+	return e.Interactive && (e.AssumeTerm || term.IsTerminal())
+}
+
+func (e *Executor) newPrompter() *input.Prompter {
+	return &input.Prompter{
+		Stdin:  e.Stdin,
+		Stdout: e.Stdout,
+		Stderr: e.Stderr,
+	}
+}
+
+// promptDepsVars traverses the dependency tree, collects all missing required
+// variables, and prompts for them upfront. This is used for deps which execute
+// in parallel, so all prompts must happen before execution to avoid interleaving.
+// Prompted values are stored in e.promptedVars for injection into task calls.
+func (e *Executor) promptDepsVars(calls []*Call) error {
+	if !e.canPrompt() {
 		return nil
 	}
 
-	var missingVars []errors.MissingVar
-	for _, requiredVar := range t.Requires.Vars {
-		_, ok := t.Vars.Get(requiredVar.Name)
-		if !ok {
-			missingVars = append(missingVars, errors.MissingVar{
-				Name:          requiredVar.Name,
-				AllowedValues: requiredVar.Enum,
-			})
+	// Collect all missing vars from the dependency tree
+	visited := make(map[string]bool)
+	varsMap := make(map[string]*ast.VarsWithValidation)
+
+	var collect func(call *Call) error
+	collect = func(call *Call) error {
+		compiledTask, err := e.FastCompiledTask(call)
+		if err != nil {
+			return err
+		}
+
+		for _, v := range getMissingRequiredVars(compiledTask) {
+			if _, exists := varsMap[v.Name]; !exists {
+				varsMap[v.Name] = v
+			}
+		}
+
+		// Check visited AFTER collecting vars to handle duplicate task calls with different vars
+		if visited[call.Task] {
+			return nil
+		}
+		visited[call.Task] = true
+
+		for _, dep := range compiledTask.Deps {
+			depCall := &Call{
+				Task:   dep.Task,
+				Vars:   dep.Vars,
+				Silent: dep.Silent,
+			}
+			if err := collect(depCall); err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}
+
+	for _, call := range calls {
+		if err := collect(call); err != nil {
+			return err
 		}
 	}
 
-	if len(missingVars) > 0 {
-		return &errors.TaskMissingRequiredVarsError{
-			TaskName:    t.Name(),
-			MissingVars: missingVars,
+	if len(varsMap) == 0 {
+		return nil
+	}
+
+	prompter := e.newPrompter()
+	e.promptedVars = ast.NewVars()
+
+	for _, v := range varsMap {
+		value, err := prompter.Prompt(v.Name, v.Enum)
+		if err != nil {
+			if errors.Is(err, input.ErrCancelled) {
+				return &errors.TaskCancelledByUserError{TaskName: "interactive prompt"}
+			}
+			return err
 		}
+		e.promptedVars.Set(v.Name, ast.Var{Value: value})
 	}
 
 	return nil
 }
 
+// promptTaskVars prompts for any missing required vars from a single task.
+// Used for sequential task calls (cmds) where we can prompt just-in-time.
+// Returns true if any vars were prompted (caller should recompile the task).
+func (e *Executor) promptTaskVars(t *ast.Task, call *Call) (bool, error) {
+	if !e.canPrompt() || t.Requires == nil || len(t.Requires.Vars) == 0 {
+		return false, nil
+	}
+
+	// Find missing vars, excluding already prompted ones
+	var missing []*ast.VarsWithValidation
+	for _, v := range getMissingRequiredVars(t) {
+		if e.promptedVars != nil {
+			if _, ok := e.promptedVars.Get(v.Name); ok {
+				continue
+			}
+		}
+		missing = append(missing, v)
+	}
+
+	if len(missing) == 0 {
+		return false, nil
+	}
+
+	prompter := e.newPrompter()
+
+	for _, v := range missing {
+		value, err := prompter.Prompt(v.Name, v.Enum)
+		if err != nil {
+			if errors.Is(err, input.ErrCancelled) {
+				return false, &errors.TaskCancelledByUserError{TaskName: t.Name()}
+			}
+			return false, err
+		}
+
+		// Add to call.Vars for recompilation
+		if call.Vars == nil {
+			call.Vars = ast.NewVars()
+		}
+		call.Vars.Set(v.Name, ast.Var{Value: value})
+
+		// Cache for reuse by other tasks
+		if e.promptedVars == nil {
+			e.promptedVars = ast.NewVars()
+		}
+		e.promptedVars.Set(v.Name, ast.Var{Value: value})
+	}
+
+	return true, nil
+}
+
+// getMissingRequiredVars returns required vars that are not set in the task's vars.
+func getMissingRequiredVars(t *ast.Task) []*ast.VarsWithValidation {
+	if t.Requires == nil {
+		return nil
+	}
+	var missing []*ast.VarsWithValidation
+	for _, v := range t.Requires.Vars {
+		if _, ok := t.Vars.Get(v.Name); !ok {
+			missing = append(missing, v)
+		}
+	}
+	return missing
+}
+
+func (e *Executor) areTaskRequiredVarsSet(t *ast.Task) error {
+	missing := getMissingRequiredVars(t)
+	if len(missing) == 0 {
+		return nil
+	}
+
+	missingVars := make([]errors.MissingVar, len(missing))
+	for i, v := range missing {
+		missingVars[i] = errors.MissingVar{
+			Name:          v.Name,
+			AllowedValues: v.Enum,
+		}
+	}
+
+	return &errors.TaskMissingRequiredVarsError{
+		TaskName:    t.Name(),
+		MissingVars: missingVars,
+	}
+}
+
 func (e *Executor) areTaskRequiredVarsAllowedValuesSet(t *ast.Task) error {
 	if t.Requires == nil || len(t.Requires.Vars) == 0 {
 		return nil
@@ -50,7 +195,6 @@ func (e *Executor) areTaskRequiredVarsAllowedValuesSet(t *ast.Task) error {
 				Name:  requiredVar.Name,
 			})
 		}
-
 	}
 
 	if len(notAllowedValuesVars) > 0 {