From 35ea4e0460e756b7a5e0894f442f265ab39d3610 Mon Sep 17 00:00:00 2001
From: Valentin Maerten <maerten.valentin@gmail.com>
Date: Thu, 20 Feb 2025 20:08:14 +0100
Subject: [PATCH] feat: display allowed values when vars are not provided
 (#2052)

---
 errors/errors_task.go          | 36 ++++++++++++++++++++++++----------
 requires.go                    | 11 +++++++----
 task_test.go                   | 13 +++++++++---
 testdata/requires/Taskfile.yml |  2 +-
 4 files changed, 44 insertions(+), 18 deletions(-)

diff --git a/errors/errors_task.go b/errors/errors_task.go
index 3349eb22..8e840c79 100644
--- a/errors/errors_task.go
+++ b/errors/errors_task.go
@@ -141,21 +141,37 @@ func (err *TaskCancelledNoTerminalError) Code() int {
 	return CodeTaskCancelled
 }
 
-// TaskMissingRequiredVars is returned when a task is missing required variables.
-type TaskMissingRequiredVars struct {
+// TaskMissingRequiredVarsError is returned when a task is missing required variables.
+
+type MissingVar struct {
+	Name          string
+	AllowedValues []string
+}
+type TaskMissingRequiredVarsError struct {
 	TaskName    string
-	MissingVars []string
+	MissingVars []MissingVar
 }
 
-func (err *TaskMissingRequiredVars) Error() string {
+func (v MissingVar) String() string {
+	if len(v.AllowedValues) == 0 {
+		return v.Name
+	}
+	return fmt.Sprintf("%s (allowed values: %v)", v.Name, v.AllowedValues)
+}
+
+func (err *TaskMissingRequiredVarsError) Error() string {
+	var vars []string
+	for _, v := range err.MissingVars {
+		vars = append(vars, v.String())
+	}
+
 	return fmt.Sprintf(
 		`task: Task %q cancelled because it is missing required variables: %s`,
 		err.TaskName,
-		strings.Join(err.MissingVars, ", "),
-	)
+		strings.Join(vars, ", "))
 }
 
-func (err *TaskMissingRequiredVars) Code() int {
+func (err *TaskMissingRequiredVarsError) Code() int {
 	return CodeTaskMissingRequiredVars
 }
 
@@ -165,12 +181,12 @@ type NotAllowedVar struct {
 	Name  string
 }
 
-type TaskNotAllowedVars struct {
+type TaskNotAllowedVarsError struct {
 	TaskName       string
 	NotAllowedVars []NotAllowedVar
 }
 
-func (err *TaskNotAllowedVars) Error() string {
+func (err *TaskNotAllowedVarsError) Error() string {
 	var builder strings.Builder
 
 	builder.WriteString(fmt.Sprintf("task: Task %q cancelled because it is missing required variables:\n", err.TaskName))
@@ -181,6 +197,6 @@ func (err *TaskNotAllowedVars) Error() string {
 	return builder.String()
 }
 
-func (err *TaskNotAllowedVars) Code() int {
+func (err *TaskNotAllowedVarsError) Code() int {
 	return CodeTaskNotAllowedVars
 }
diff --git a/requires.go b/requires.go
index 010a9964..119b073b 100644
--- a/requires.go
+++ b/requires.go
@@ -12,16 +12,19 @@ func (e *Executor) areTaskRequiredVarsSet(t *ast.Task) error {
 		return nil
 	}
 
-	var missingVars []string
+	var missingVars []errors.MissingVar
 	for _, requiredVar := range t.Requires.Vars {
 		_, ok := t.Vars.Get(requiredVar.Name)
 		if !ok {
-			missingVars = append(missingVars, requiredVar.Name)
+			missingVars = append(missingVars, errors.MissingVar{
+				Name:          requiredVar.Name,
+				AllowedValues: requiredVar.Enum,
+			})
 		}
 	}
 
 	if len(missingVars) > 0 {
-		return &errors.TaskMissingRequiredVars{
+		return &errors.TaskMissingRequiredVarsError{
 			TaskName:    t.Name(),
 			MissingVars: missingVars,
 		}
@@ -51,7 +54,7 @@ func (e *Executor) areTaskRequiredVarsAllowedValuesSet(t *ast.Task) error {
 	}
 
 	if len(notAllowedValuesVars) > 0 {
-		return &errors.TaskNotAllowedVars{
+		return &errors.TaskNotAllowedVarsError{
 			TaskName:       t.Name(),
 			NotAllowedVars: notAllowedValuesVars,
 		}
diff --git a/task_test.go b/task_test.go
index b1a7ed4a..dabdef98 100644
--- a/task_test.go
+++ b/task_test.go
@@ -186,23 +186,30 @@ func TestRequires(t *testing.T) {
 
 	vars := ast.NewVars()
 	vars.Set("FOO", ast.Var{Value: "bar"})
+
 	require.NoError(t, e.Run(context.Background(), &ast.Call{
 		Task: "missing-var",
 		Vars: vars,
 	}))
 	buff.Reset()
 
+	vars.Set("ENV", ast.Var{Value: "dev"})
 	require.NoError(t, e.Setup())
 	require.ErrorContains(t, e.Run(context.Background(), &ast.Call{Task: "validation-var", Vars: vars}), "task: Task \"validation-var\" cancelled because it is missing required variables:\n  - FOO has an invalid value : 'bar' (allowed values : [one two])")
 	buff.Reset()
 
 	require.NoError(t, e.Setup())
-	require.NoError(t, e.Run(context.Background(), &ast.Call{Task: "validation-var-dynamic", Vars: vars}))
+	vars.Set("FOO", ast.Var{Value: "one"})
+	require.NoError(t, e.Run(context.Background(), &ast.Call{Task: "validation-var", Vars: vars}))
+	buff.Reset()
+
+	vars = ast.NewVars()
+	require.NoError(t, e.Setup())
+	require.ErrorContains(t, e.Run(context.Background(), &ast.Call{Task: "validation-var", Vars: vars}), "task: Task \"validation-var\" cancelled because it is missing required variables: ENV, FOO (allowed values: [one two])")
 	buff.Reset()
 
 	require.NoError(t, e.Setup())
-	vars.Set("FOO", ast.Var{Value: "one"})
-	require.NoError(t, e.Run(context.Background(), &ast.Call{Task: "validation-var", Vars: vars}))
+	require.NoError(t, e.Run(context.Background(), &ast.Call{Task: "validation-var-dynamic", Vars: vars}))
 	buff.Reset()
 
 	require.NoError(t, e.Setup())
diff --git a/testdata/requires/Taskfile.yml b/testdata/requires/Taskfile.yml
index 1bc638e4..75b977a0 100644
--- a/testdata/requires/Taskfile.yml
+++ b/testdata/requires/Taskfile.yml
@@ -33,10 +33,10 @@ tasks:
   validation-var:
     requires:
       vars:
+        - ENV
         - name: FOO
           enum: ['one', 'two']
 
-
   require-before-compile:
     requires:
       vars: [ MY_VAR ]