s3: keep the list marker exclusive for versioned objects (#10496)

* s3: keep the list marker exclusive for versioned objects

A versioned object lives in a "<key>.versions" directory, so the entry name
never matched the marker and start-after/marker returned the marker key itself.

* s3: match the list marker against the raw entry name too

A backend that echoes the marker it was given returns the ".versions" directory
name, which no longer matched once the comparison used the object name alone.
Cover both, and unit test each half.

test/s3/versioning/s3_versioning_list_marker_test.go

@@ -0,0 +1,62 @@
+package s3api
+
+import (
+	"context"
+	"testing"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+	"github.com/aws/aws-sdk-go-v2/service/s3/types"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestVersionedListMarkerIsExclusive covers start-after and marker on a versioned bucket,
+// where an object is stored in a "<key>.versions" directory and so never matches the
+// marker by entry name.
+func TestVersionedListMarkerIsExclusive(t *testing.T) {
+	client := getS3Client(t)
+	bucketName := getNewBucketName()
+
+	createBucket(t, client, bucketName)
+	defer deleteBucket(t, client, bucketName)
+	enableVersioning(t, client, bucketName)
+
+	for _, key := range []string{"file-0", "file-1", "file-2", "logs/file-0", "logs/file-1", "logs/file-2"} {
+		putObject(t, client, bucketName, key, "content")
+	}
+
+	listV2 := func(prefix, startAfter string) []string {
+		t.Helper()
+		resp, err := client.ListObjectsV2(context.TODO(), &s3.ListObjectsV2Input{
+			Bucket:     aws.String(bucketName),
+			Prefix:     aws.String(prefix),
+			StartAfter: aws.String(startAfter),
+		})
+		require.NoError(t, err)
+		return contentKeys(resp.Contents)
+	}
+	listV1 := func(prefix, marker string) []string {
+		t.Helper()
+		resp, err := client.ListObjects(context.TODO(), &s3.ListObjectsInput{
+			Bucket: aws.String(bucketName),
+			Prefix: aws.String(prefix),
+			Marker: aws.String(marker),
+		})
+		require.NoError(t, err)
+		return contentKeys(resp.Contents)
+	}
+
+	assert.Equal(t, []string{"file-2"}, listV2("file-", "file-1"))
+	assert.Equal(t, []string{"file-2"}, listV1("file-", "file-1"))
+	assert.Equal(t, []string{"logs/file-2"}, listV2("logs/", "logs/file-1"))
+	assert.Equal(t, []string{"logs/file-2"}, listV1("logs/", "logs/file-1"))
+}
+
+func contentKeys(contents []types.Object) []string {
+	keys := make([]string, 0, len(contents))
+	for _, c := range contents {
+		keys = append(keys, *c.Key)
+	}
+	return keys
+}