[MM-57034]: Check for s3 object is File or Directory (#26837)

* check for path when number of object is one

* add test and updated condition to check for path

* updated test and removed string trim

* using exported method

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/platform/shared/filestore/s3store.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"crypto/tls"
 	"io"
+	"io/fs"
 	"net/http"
 	"net/url"
 	"os"
@@ -641,6 +642,7 @@ func (b *S3FileBackend) listDirectory(path string, recursion bool) ([]string, er
 	var paths []string
 	ctx, cancel := context.WithTimeout(context.Background(), b.timeout)
 	defer cancel()
+	var count int
 	for object := range b.client.ListObjects(ctx, b.bucket, opts) {
 		if object.Err != nil {
 			return nil, errors.Wrapf(object.Err, "unable to list the directory %s", path)
@@ -652,6 +654,12 @@ func (b *S3FileBackend) listDirectory(path string, recursion bool) ([]string, er
 		if trimmed != "" {
 			paths = append(paths, trimmed)
 		}
+		count++
+	}
+	// Check if only one item was returned and it matches the path prefix
+	if count == 1 && len(paths) > 0 && strings.TrimRight(path, "/") == paths[0] {
+		// Return a fs.PathError to maintain consistency
+		return nil, &fs.PathError{Op: "readdir", Path: path, Err: fs.ErrNotExist}
 	}
 
 	return paths, nil

server/platform/shared/filestore/s3store_test.go

@@ -4,12 +4,14 @@
 package filestore
 
 import (
+	"bytes"
 	"context"
 	"crypto/rand"
 	"encoding/base64"
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"net/http/httptest"
 	"net/http/httputil"
 	"net/url"
@@ -20,6 +22,7 @@ import (
 
 	"github.com/mattermost/mattermost/server/public/model"
 	s3 "github.com/minio/minio-go/v7"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -320,3 +323,59 @@ func (fc fauxCloser) Close() error {
 	fc.s3WithCancel.cancel()
 	return fc.closeErr
 }
+
+func TestListDirectory(t *testing.T) {
+	s3Host := os.Getenv("CI_MINIO_HOST")
+	if s3Host == "" {
+		s3Host = "localhost"
+	}
+
+	s3Port := os.Getenv("CI_MINIO_PORT")
+	if s3Port == "" {
+		s3Port = "9000"
+	}
+
+	s3Endpoint := fmt.Sprintf("%s:%s", s3Host, s3Port)
+
+	cfg := FileBackendSettings{
+		DriverName:                         driverS3,
+		AmazonS3AccessKeyId:                "minioaccesskey",
+		AmazonS3SecretAccessKey:            "miniosecretkey",
+		AmazonS3Bucket:                     "mattermost-test-1",
+		AmazonS3Region:                     "",
+		AmazonS3Endpoint:                   s3Endpoint,
+		AmazonS3PathPrefix:                 "",
+		AmazonS3SSL:                        false,
+		AmazonS3SSE:                        false,
+		AmazonS3RequestTimeoutMilliseconds: 5000,
+	}
+
+	fileBackend, err := NewS3FileBackend(cfg)
+	require.NoError(t, err)
+
+	found, err := fileBackend.client.BucketExists(context.Background(), cfg.AmazonS3Bucket)
+	require.NoError(t, err)
+
+	if !found {
+		err = fileBackend.MakeBucket()
+		require.NoError(t, err)
+	}
+
+	fileBackend.pathPrefix = "19700101/"
+	require.NoError(t, err)
+	b := []byte("test")
+
+	path1 := "19700101/" + randomString() + ".txt"
+	_, err = fileBackend.WriteFile(bytes.NewReader(b), path1)
+	require.NoError(t, err, "Failed to write file1 to S3")
+
+	_, err = fileBackend.ListDirectory("")
+	var pErr *fs.PathError
+	assert.True(t, errors.As(err, &pErr), "error is not of type fs.PathError")
+
+	err = fileBackend.RemoveFile(path1)
+	require.NoError(t, err, "Failed to remove file1 from S3")
+
+	err = fileBackend.RemoveDirectory("19700101")
+	require.NoError(t, err)
+}