Defer statements could possibly void stored error values (#798)

cmd/backup/archive.go

@@ -8,6 +8,7 @@ package main
 
 import (
 	"archive/tar"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -164,7 +165,7 @@ func writeTarball(path string, tarWriter *tar.Writer, prefix string) (returnErr
 		return
 	}
 	defer func() {
-		returnErr = file.Close()
+		returnErr = errors.Join(returnErr, file.Close())
 	}()
 
 	_, err = io.Copy(tarWriter, file)

internal/storage/dropbox/dropbox.go

@@ -3,6 +3,7 @@ package dropbox
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"net/url"
 	"os"
@@ -111,7 +112,7 @@ func (b *dropboxStorage) Copy(file string) (returnErr error) {
 		return
 	}
 	defer func() {
-		returnErr = r.Close()
+		returnErr = errors.Join(returnErr, r.Close())
 	}()
 
 	// Start new upload session and get session id

internal/storage/googledrive/googledrive.go

@@ -5,6 +5,7 @@ package googledrive
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -97,7 +98,7 @@ func (b *googleDriveStorage) Copy(file string) (returnErr error) {
 		return
 	}
 	defer func() {
-		returnErr = f.Close()
+		returnErr = errors.Join(returnErr, f.Close())
 	}()
 
 	driveFile := &drive.File{Name: name}

internal/storage/local/local.go

@@ -155,7 +155,7 @@ func copyFile(src, dst string) (returnErr error) {
 		return
 	}
 	defer func() {
-		returnErr = in.Close()
+		returnErr = errors.Join(returnErr, in.Close())
 	}()
 
 	out, err := os.Create(dst)

internal/storage/ssh/ssh.go

@@ -110,7 +110,8 @@ func (b *sshStorage) Name() string {
 // Copy copies the given file to the SSH storage backend.
 func (b *sshStorage) Copy(file string) (returnErr error) {
 	if err := b.sftpClient.MkdirAll(b.DestinationPath); err != nil {
-		return errwrap.Wrap(err, "error ensuring destination directory")
+		returnErr = errwrap.Wrap(err, "error ensuring destination directory")
+		return
 	}
 
 	source, err := os.Open(file)
@@ -120,7 +121,7 @@ func (b *sshStorage) Copy(file string) (returnErr error) {
 		return
 	}
 	defer func() {
-		returnErr = source.Close()
+		returnErr = errors.Join(returnErr, source.Close())
 	}()
 
 	destination, err := b.sftpClient.Create(path.Join(b.DestinationPath, name))
@@ -129,7 +130,7 @@ func (b *sshStorage) Copy(file string) (returnErr error) {
 		return
 	}
 	defer func() {
-		returnErr = destination.Close()
+		returnErr = errors.Join(returnErr, destination.Close())
 	}()
 
 	chunk := make([]byte, 1e9)