feat: add ability to specify which vars are required (#1204)

requires.go

@@ -0,0 +1,35 @@
+package task
+
+import (
+	"context"
+
+	"github.com/go-task/task/v3/errors"
+	"github.com/go-task/task/v3/taskfile"
+)
+
+func (e *Executor) areTaskRequiredVarsSet(ctx context.Context, t *taskfile.Task, call taskfile.Call) error {
+	if t.Requires == nil || len(t.Requires.Vars) == 0 {
+		return nil
+	}
+
+	vars, err := e.Compiler.GetVariables(t, call)
+	if err != nil {
+		return err
+	}
+
+	var missingVars []string
+	for _, requiredVar := range t.Requires.Vars {
+		if !vars.Exists(requiredVar) {
+			missingVars = append(missingVars, requiredVar)
+		}
+	}
+
+	if len(missingVars) > 0 {
+		return &errors.TaskMissingRequiredVars{
+			TaskName:    t.Name(),
+			MissingVars: missingVars,
+		}
+	}
+
+	return nil
+}