From 83b83f7768389f7ae8c1336ebc1d027376138bee Mon Sep 17 00:00:00 2001
From: Sean Turner <30396892+seanturner026@users.noreply.github.com>
Date: Thu, 13 Nov 2025 14:50:47 +0100
Subject: [PATCH] s3: add support for --upload-header If-Match and
 If-None-Match

The If-Match and If-None-Match headers were being dropped rather
than implemented in the Put Object request to S3. These headers
make requests conditional which allow AWS S3 Bucket Policies to
prevent Object overwriting.
---
 backend/s3/s3.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/backend/s3/s3.go b/backend/s3/s3.go
index c12a97619..c2c3392dd 100644
--- a/backend/s3/s3.go
+++ b/backend/s3/s3.go
@@ -4552,6 +4552,10 @@ func (o *Object) prepareUpload(ctx context.Context, src fs.ObjectInfo, options [
 			ui.req.ContentLanguage = aws.String(value)
 		case "content-type":
 			ui.req.ContentType = aws.String(value)
+		case "if-match":
+			ui.req.IfMatch = aws.String(value)
+		case "if-none-match":
+			ui.req.IfNoneMatch = aws.String(value)
 		case "x-amz-tagging":
 			ui.req.Tagging = aws.String(value)
 		default: