response: sort entries before final .Create()

.gitignore

@@ -4,6 +4,8 @@
 *.a
 *.so
 
+.DS_Store
+
 # Folders
 _obj
 _test

pkg/response/file_transformer.go

@@ -1,10 +1,12 @@
 package response
 
 import (
+	"cmp"
 	"context"
 	"fmt"
 	"math/rand"
 	"path/filepath"
+	"slices"
 	"time"
 
 	"github.com/moov-io/ach"
@@ -99,6 +101,11 @@ func (ft *FileTransfomer) Transform(ctx context.Context, file *ach.File) error {
 		for delay, batchesByCategory := range outBatches {
 			for _, batch := range batchesByCategory {
 				if entries = (*batch).GetEntries(); len(entries) > 0 {
+					// Sort the entries before the final build
+					slices.SortFunc(entries, func(e1, e2 *ach.EntryDetail) int {
+						return cmp.Compare(e1.TraceNumber, e2.TraceNumber)
+					})
+
 					if err := (*batch).Create(); err != nil {
 						return fmt.Errorf("transform batch[%d] create error: %v", i, err)
 					}

pkg/response/file_transformer_test.go

@@ -59,6 +59,9 @@ var (
 			Value: 62_01,
 		},
 	}
+	matchRoutingNumber = service.Match{
+		RoutingNumber: "083000137",
+	}
 
 	actionReturn = service.Action{
 		Return: &service.Return{
@@ -1040,3 +1043,23 @@ func TestFileTransformer_CTX(t *testing.T) {
 		require.Equal(t, "C01", entries[0].Addenda98.ChangeCode)
 	})
 }
+
+func TestFileTransform_Sorted(t *testing.T) {
+	resp := service.Response{
+		Match:  matchRoutingNumber,
+		Action: actionReturn,
+	}
+	fileTransformer, _ := testFileTransformer(t, resp)
+
+	// read the file
+	achIn, err := ach.ReadFile(filepath.Join("..", "..", "testdata", "out-of-order.ach"))
+	require.NoError(t, err)
+	require.NotNil(t, achIn)
+
+	// transform the file several times making sure we don't error
+	// The code can sometimes reorder entries which causes the transform to fail
+	for i := 0; i < 100; i++ {
+		err := fileTransformer.Transform(context.Background(), achIn)
+		require.NoError(t, err)
+	}
+}

testdata/out-of-order.ach

@@ -0,0 +1,7 @@
+101 011000015 2214757862412170450A094101FRBBOSTON              MOOVODFI                       
+5200BT* Matt's Biz                      MjZjNDQzY2CCD12275-1         241217   1221475780000004
+622083000137345452324        0000000180               Matt Ryavec Co        cc0221475780029324
+622083000137121212           0000000100               Matt Ryavec Co        390221475780109254
+82000000020016600026000000000000000000000280MjZjNDQzY2                         221475780000004
+9000014000005000000190371392563000000509793000000509793                                       
+9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999