From a4f4e1b430863a805ef676ce1c24fb58543fdd15 Mon Sep 17 00:00:00 2001
From: Pete Davison <pd93.uk@outlook.com>
Date: Mon, 2 Sep 2024 21:30:00 +0000
Subject: [PATCH] fix: matrix loops should be deterministic

---
 taskfile/ast/for.go | 11 ++++++-----
 variables.go        | 22 ++++++++--------------
 2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/taskfile/ast/for.go b/taskfile/ast/for.go
index 5a87acf2db..35d7ce7f60 100644
--- a/taskfile/ast/for.go
+++ b/taskfile/ast/for.go
@@ -5,12 +5,13 @@ import (
 
 	"github.com/go-task/task/v3/errors"
 	"github.com/go-task/task/v3/internal/deepcopy"
+	"github.com/go-task/task/v3/internal/omap"
 )
 
 type For struct {
 	From   string
 	List   []any
-	Matrix map[string][]any
+	Matrix omap.OrderedMap[string, []any]
 	Var    string
 	Split  string
 	As     string
@@ -37,7 +38,7 @@ func (f *For) UnmarshalYAML(node *yaml.Node) error {
 
 	case yaml.MappingNode:
 		var forStruct struct {
-			Matrix map[string][]any
+			Matrix omap.OrderedMap[string, []any]
 			Var    string
 			Split  string
 			As     string
@@ -45,10 +46,10 @@ func (f *For) UnmarshalYAML(node *yaml.Node) error {
 		if err := node.Decode(&forStruct); err != nil {
 			return errors.NewTaskfileDecodeError(err, node)
 		}
-		if forStruct.Var == "" && forStruct.Matrix == nil {
+		if forStruct.Var == "" && forStruct.Matrix.Len() == 0 {
 			return errors.NewTaskfileDecodeError(nil, node).WithMessage("invalid keys in for")
 		}
-		if forStruct.Var != "" && forStruct.Matrix != nil {
+		if forStruct.Var != "" && forStruct.Matrix.Len() != 0 {
 			return errors.NewTaskfileDecodeError(nil, node).WithMessage("cannot use both var and matrix in for")
 		}
 		f.Matrix = forStruct.Matrix
@@ -68,7 +69,7 @@ func (f *For) DeepCopy() *For {
 	return &For{
 		From:   f.From,
 		List:   deepcopy.Slice(f.List),
-		Matrix: deepcopy.Map(f.Matrix),
+		Matrix: f.Matrix.DeepCopy(),
 		Var:    f.Var,
 		Split:  f.Split,
 		As:     f.As,
diff --git a/variables.go b/variables.go
index 22e47aa9df..cfdb70ae46 100644
--- a/variables.go
+++ b/variables.go
@@ -11,6 +11,7 @@ import (
 	"github.com/go-task/task/v3/internal/execext"
 	"github.com/go-task/task/v3/internal/filepathext"
 	"github.com/go-task/task/v3/internal/fingerprint"
+	"github.com/go-task/task/v3/internal/omap"
 	"github.com/go-task/task/v3/internal/templater"
 	"github.com/go-task/task/v3/taskfile/ast"
 )
@@ -272,7 +273,7 @@ func itemsFromFor(
 	var keys []string // The list of keys to loop over (only if looping over a map)
 	var values []any  // The list of values to loop over
 	// Get the list from a matrix
-	if f.Matrix != nil {
+	if f.Matrix.Len() != 0 {
 		return asAnySlice(product(f.Matrix)), nil, nil
 	}
 	// Get the list from the explicit for list
@@ -328,24 +329,16 @@ func itemsFromFor(
 }
 
 // product generates the cartesian product of the input map of slices.
-func product(inputMap map[string][]any) []map[string]any {
-	if len(inputMap) == 0 {
+func product(inputMap omap.OrderedMap[string, []any]) []map[string]any {
+	if inputMap.Len() == 0 {
 		return nil
 	}
 
-	// Extract the keys and corresponding slices
-	keys := make([]string, 0, len(inputMap))
-	slices := make([][]any, 0, len(inputMap))
-	for key, slice := range inputMap {
-		keys = append(keys, key)
-		slices = append(slices, slice)
-	}
-
 	// Start with an empty product result
 	result := []map[string]any{{}}
 
 	// Iterate over each slice in the slices
-	for i, slice := range slices {
+	_ = inputMap.Range(func(key string, slice []any) error {
 		var newResult []map[string]any
 
 		// For each combination in the current result
@@ -358,14 +351,15 @@ func product(inputMap map[string][]any) []map[string]any {
 					newComb[k] = v
 				}
 				// Add the current item with the corresponding key
-				newComb[keys[i]] = item
+				newComb[key] = item
 				newResult = append(newResult, newComb)
 			}
 		}
 
 		// Update result with the new combinations
 		result = newResult
-	}
+		return nil
+	})
 
 	return result
 }