From 2da7ddc39971f41bfa761466b43511a61ef2ed32 Mon Sep 17 00:00:00 2001
From: Pete Davison <pd93.uk@outlook.com>
Date: Sat, 14 Jan 2023 13:45:52 -0600
Subject: [PATCH] chore: optimize task filtering (#982)

---
 help.go |  9 +++++---
 task.go | 71 ++++++++++++++++++++++++++-------------------------------
 2 files changed, 38 insertions(+), 42 deletions(-)

diff --git a/help.go b/help.go
index 15a51fed..d0eca8f9 100644
--- a/help.go
+++ b/help.go
@@ -51,10 +51,10 @@ func (o ListOptions) Validate() error {
 // Filters returns the slice of FilterFunc which filters a list
 // of taskfile.Task according to the given ListOptions
 func (o ListOptions) Filters() []FilterFunc {
-	filters := []FilterFunc{FilterOutInternal()}
+	filters := []FilterFunc{FilterOutInternal}
 
 	if o.ListOnlyTasksWithDescriptions {
-		filters = append(filters, FilterOutNoDesc())
+		filters = append(filters, FilterOutNoDesc)
 	}
 
 	return filters
@@ -65,7 +65,10 @@ func (o ListOptions) Filters() []FilterFunc {
 // The function returns a boolean indicating whether tasks were found
 // and an error if one was encountered while preparing the output.
 func (e *Executor) ListTasks(o ListOptions) (bool, error) {
-	tasks := e.GetTaskList(o.Filters()...)
+	tasks, err := e.GetTaskList(o.Filters()...)
+	if err != nil {
+		return false, err
+	}
 	if o.FormatTaskListAsJSON {
 		output, err := e.ToEditorOutput(tasks)
 		if err != nil {
diff --git a/task.go b/task.go
index 4c774d4c..7a0d3ffd 100644
--- a/task.go
+++ b/task.go
@@ -400,23 +400,39 @@ func (e *Executor) GetTask(call taskfile.Call) (*taskfile.Task, error) {
 	return matchingTask, nil
 }
 
-type FilterFunc func(tasks []*taskfile.Task) []*taskfile.Task
+type FilterFunc func(task *taskfile.Task) bool
 
-func (e *Executor) GetTaskList(filters ...FilterFunc) []*taskfile.Task {
+func (e *Executor) GetTaskList(filters ...FilterFunc) ([]*taskfile.Task, error) {
 	tasks := make([]*taskfile.Task, 0, len(e.Taskfile.Tasks))
 
+	// Create an error group to wait for each task to be compiled
+	var g errgroup.Group
+
 	// Fetch and compile the list of tasks
-	for _, task := range e.Taskfile.Tasks {
-		compiledTask, err := e.FastCompiledTask(taskfile.Call{Task: task.Task})
-		if err == nil {
-			task = compiledTask
-		}
-		tasks = append(tasks, task)
+	for key := range e.Taskfile.Tasks {
+		task := e.Taskfile.Tasks[key]
+		g.Go(func() error {
+
+			// Check if we should filter the task
+			for _, filter := range filters {
+				if filter(task) {
+					return nil
+				}
+			}
+
+			// Compile the task
+			compiledTask, err := e.FastCompiledTask(taskfile.Call{Task: task.Task})
+			if err == nil {
+				task = compiledTask
+			}
+			tasks = append(tasks, task)
+			return nil
+		})
 	}
 
-	// Filter the tasks
-	for _, filter := range filters {
-		tasks = filter(tasks)
+	// Wait for all the go routines to finish
+	if err := g.Wait(); err != nil {
+		return nil, err
 	}
 
 	// Sort the tasks.
@@ -434,40 +450,17 @@ func (e *Executor) GetTaskList(filters ...FilterFunc) []*taskfile.Task {
 		return false
 	})
 
-	return tasks
-}
-
-// Filter is a generic task filtering function. It will remove each task in the
-// slice where the result of the given function is true.
-func Filter(f func(task *taskfile.Task) bool) FilterFunc {
-	return func(tasks []*taskfile.Task) []*taskfile.Task {
-		shift := 0
-		for _, task := range tasks {
-			if !f(task) {
-				tasks[shift] = task
-				shift++
-			}
-		}
-		// This loop stops any memory leaks
-		for j := shift; j < len(tasks); j++ {
-			tasks[j] = nil
-		}
-		return slices.Clip(tasks[:shift])
-	}
+	return tasks, nil
 }
 
 // FilterOutNoDesc removes all tasks that do not contain a description.
-func FilterOutNoDesc() FilterFunc {
-	return Filter(func(task *taskfile.Task) bool {
-		return task.Desc == ""
-	})
+func FilterOutNoDesc(task *taskfile.Task) bool {
+	return task.Desc == ""
 }
 
 // FilterOutInternal removes all tasks that are marked as internal.
-func FilterOutInternal() FilterFunc {
-	return Filter(func(task *taskfile.Task) bool {
-		return task.Internal
-	})
+func FilterOutInternal(task *taskfile.Task) bool {
+	return task.Internal
 }
 
 func shouldRunOnCurrentPlatform(platforms []*taskfile.Platform) bool {