From dc31696e5314554fa7e205696f680460bb7f2ca2 Mon Sep 17 00:00:00 2001
From: Ben McClelland <ben.mcclelland@versity.com>
Date: Sat, 28 Feb 2026 15:37:59 -0800
Subject: [PATCH] fix: azure ListBuckets pagination to use client-side
 continuation tokens

Azure's ListContainers Marker parameter requires an opaque internal token
(e.g. /accountname/containername) rather than a plain container name, so
passing MaxResults and our ContinuationToken directly to the Azure API
caused 400 OutOfRangeInput errors. Rework ListBuckets to iterate all Azure
pages client-side, skip entries at or before the ContinuationToken (matching
the posix backend's "start after" semantics), and stop once MaxBuckets items
have been collected, setting ContinuationToken to the last returned bucket
name. This avoids using Azure's NextMarker entirely and correctly handles
both unpaginated and paginated requests.
---
 backend/azure/azure.go | 67 +++++++++++++++++++++++-------------------
 1 file changed, 37 insertions(+), 30 deletions(-)

diff --git a/backend/azure/azure.go b/backend/azure/azure.go
index bb6f420a..ecaaf91e 100644
--- a/backend/azure/azure.go
+++ b/backend/azure/azure.go
@@ -216,54 +216,61 @@ func (az *Azure) CreateBucket(ctx context.Context, input *s3.CreateBucketInput,
 }
 
 func (az *Azure) ListBuckets(ctx context.Context, input s3response.ListBucketsInput) (s3response.ListAllMyBucketsResult, error) {
-	pager := az.client.NewListContainersPager(
-		&service.ListContainersOptions{
-			Include: service.ListContainersInclude{
-				Metadata: true,
-			},
-			Marker:     &input.ContinuationToken,
-			MaxResults: &input.MaxBuckets,
-			Prefix:     &input.Prefix,
-		})
+	opts := &service.ListContainersOptions{
+		Include: service.ListContainersInclude{
+			Metadata: true,
+		},
+		Prefix: &input.Prefix,
+	}
+	pager := az.client.NewListContainersPager(opts)
 
 	var buckets []s3response.ListAllMyBucketsEntry
+	var cToken string
 	result := s3response.ListAllMyBucketsResult{
 		Prefix: input.Prefix,
 	}
 
-	resp, err := pager.NextPage(ctx)
-	if err != nil {
-		return result, azureErrToS3Err(err)
-	}
-	for _, v := range resp.ContainerItems {
-		if input.IsAdmin {
-			buckets = append(buckets, s3response.ListAllMyBucketsEntry{
-				Name: *v.Name,
-				// TODO: using modification date here instead of creation, is that ok?
-				CreationDate: *v.Properties.LastModified,
-			})
-		} else {
-			acl, err := getAclFromMetadata(v.Metadata, keyAclLower)
-			if err != nil {
-				return result, err
+outer:
+	for pager.More() {
+		resp, err := pager.NextPage(ctx)
+		if err != nil {
+			return result, azureErrToS3Err(err)
+		}
+		for _, v := range resp.ContainerItems {
+			// If we've already filled MaxBuckets, there is a next page — set token and stop
+			if input.MaxBuckets > 0 && int32(len(buckets)) == input.MaxBuckets {
+				cToken = buckets[len(buckets)-1].Name
+				break outer
 			}
-
-			if acl.Owner == input.Owner {
+			// Skip items at or before the continuation token (client-side "start after")
+			if input.ContinuationToken != "" && *v.Name <= input.ContinuationToken {
+				continue
+			}
+			if input.IsAdmin {
 				buckets = append(buckets, s3response.ListAllMyBucketsEntry{
 					Name: *v.Name,
 					// TODO: using modification date here instead of creation, is that ok?
 					CreationDate: *v.Properties.LastModified,
 				})
+			} else {
+				acl, err := getAclFromMetadata(v.Metadata, keyAclLower)
+				if err != nil {
+					return result, err
+				}
+				if acl.Owner == input.Owner {
+					buckets = append(buckets, s3response.ListAllMyBucketsEntry{
+						Name: *v.Name,
+						// TODO: using modification date here instead of creation, is that ok?
+						CreationDate: *v.Properties.LastModified,
+					})
+				}
 			}
 		}
 	}
 
-	if resp.NextMarker != nil {
-		result.ContinuationToken = *resp.NextMarker
-	}
-
 	result.Buckets.Bucket = buckets
 	result.Owner.ID = input.Owner
+	result.ContinuationToken = cToken
 
 	return result, nil
 }