From e708e3cf73dfc034a43230bcb49eb28fd9b6260b Mon Sep 17 00:00:00 2001
From: Pieter Noordhuis <pieter.noordhuis@databricks.com>
Date: Mon, 13 Apr 2026 22:50:52 +0200
Subject: [PATCH] Use `slices.Backward` and `slices.Reverse` for reverse
 iteration

Replace manual reverse-index loops and swap-based reversals with
`slices.Backward` and `slices.Reverse` from the standard library.

Co-authored-by: Isaac
---
 bundle/run/pipeline.go          | 8 ++++----
 bundle/run/progress/pipeline.go | 6 +++---
 cmd/apps/init.go                | 4 ++--
 cmd/root/user_agent_command.go  | 9 +++------
 libs/dagrun/dagrun.go           | 9 +++------
 libs/filer/files_client.go      | 4 ++--
 6 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/bundle/run/pipeline.go b/bundle/run/pipeline.go
index 916df54828..8dea20a50a 100644
--- a/bundle/run/pipeline.go
+++ b/bundle/run/pipeline.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"slices"
 	"time"
 
 	"github.com/databricks/cli/bundle"
@@ -63,10 +64,9 @@ func (r *pipelineRunner) logErrorEvent(ctx context.Context, pipelineId, updateId
 		return err
 	}
 	updateEvents := filterEventsByUpdateId(events, updateId)
-	// The events API returns most recent events first. We iterate in a reverse order
-	// to print the events chronologically
-	for i := len(updateEvents) - 1; i >= 0; i-- {
-		r.logEvent(ctx, updateEvents[i])
+	// The events API returns most recent events first.
+	for _, event := range slices.Backward(updateEvents) {
+		r.logEvent(ctx, event)
 	}
 	return nil
 }
diff --git a/bundle/run/progress/pipeline.go b/bundle/run/progress/pipeline.go
index a98f074f78..f12d0455fc 100644
--- a/bundle/run/progress/pipeline.go
+++ b/bundle/run/progress/pipeline.go
@@ -3,6 +3,7 @@ package progress
 import (
 	"context"
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/databricks/databricks-sdk-go"
@@ -83,9 +84,8 @@ func (l *UpdateTracker) Events(ctx context.Context) ([]ProgressEvent, error) {
 	}
 
 	var result []ProgressEvent
-	// we iterate in reverse to return events in chronological order
-	for i := len(events) - 1; i >= 0; i-- {
-		event := events[i]
+	// Return events in chronological order.
+	for _, event := range slices.Backward(events) {
 		// filter to only include update_progress and flow_progress events
 		if event.EventType == "flow_progress" || event.EventType == "update_progress" {
 			result = append(result, ProgressEvent(event))
diff --git a/cmd/apps/init.go b/cmd/apps/init.go
index 85772b6a91..5658989525 100644
--- a/cmd/apps/init.go
+++ b/cmd/apps/init.go
@@ -1404,8 +1404,8 @@ func removeEmptyDirs(root string) error {
 	if err != nil {
 		return err
 	}
-	for i := len(dirs) - 1; i >= 0; i-- {
-		_ = os.Remove(dirs[i])
+	for _, dir := range slices.Backward(dirs) {
+		_ = os.Remove(dir)
 	}
 	return nil
 }
diff --git a/cmd/root/user_agent_command.go b/cmd/root/user_agent_command.go
index 306f2d7bfa..70c7f4049a 100644
--- a/cmd/root/user_agent_command.go
+++ b/cmd/root/user_agent_command.go
@@ -2,6 +2,7 @@ package root
 
 import (
 	"context"
+	"slices"
 	"strings"
 
 	"github.com/databricks/databricks-sdk-go/useragent"
@@ -24,12 +25,8 @@ func commandString(cmd *cobra.Command) string {
 		reversed = append(reversed, p.Name())
 	})
 
-	ordered := make([]string, 0, len(reversed))
-	for i := len(reversed) - 1; i >= 0; i-- {
-		ordered = append(ordered, reversed[i])
-	}
-
-	return strings.Join(ordered, commandSeparator)
+	slices.Reverse(reversed)
+	return strings.Join(reversed, commandSeparator)
 }
 
 func withCommandInUserAgent(ctx context.Context, cmd *cobra.Command) context.Context {
diff --git a/libs/dagrun/dagrun.go b/libs/dagrun/dagrun.go
index 273c913ef3..b40fa6f10f 100644
--- a/libs/dagrun/dagrun.go
+++ b/libs/dagrun/dagrun.go
@@ -2,6 +2,7 @@ package dagrun
 
 import (
 	"fmt"
+	"slices"
 	"strings"
 	"sync"
 )
@@ -129,12 +130,8 @@ func (g *Graph) DetectCycle() error {
 							break
 						}
 					}
-					for i, j := 0, len(nodes)-1; i < j; i, j = i+1, j-1 {
-						nodes[i], nodes[j] = nodes[j], nodes[i]
-					}
-					for i, j := 0, len(edges)-1; i < j; i, j = i+1, j-1 {
-						edges[i], edges[j] = edges[j], edges[i]
-					}
+					slices.Reverse(nodes)
+					slices.Reverse(edges)
 					edges = append(edges, closeLbl)
 					return &CycleError{Nodes: nodes, Edges: edges}
 				}
diff --git a/libs/filer/files_client.go b/libs/filer/files_client.go
index 4160b9b209..6af4c598de 100644
--- a/libs/filer/files_client.go
+++ b/libs/filer/files_client.go
@@ -326,8 +326,8 @@ func (w *FilesClient) recursiveDelete(ctx context.Context, name string) error {
 	// Delete the directories in reverse order to ensure that the parent
 	// directories are deleted after the children. This is possible because
 	// fs.WalkDir walks the directories in lexicographical order.
-	for i := len(dirsToDelete) - 1; i >= 0; i-- {
-		err := w.deleteDirectory(ctx, dirsToDelete[i])
+	for _, dir := range slices.Backward(dirsToDelete) {
+		err := w.deleteDirectory(ctx, dir)
 		if err != nil {
 			return err
 		}