deja-dup can not restore long path and filenames when restored on an encrypted home directory (backuped without home encrytion)

[Christian Herzberg]

I tried to restore my deja-dup backup after a new install migrating from 14.04.x to 16.04.01. I choose to make a fresh install because need to encrypt data. Because of known bugs with encrypted swap I use the option to encrypte the user-directory.

Because of a problem with a big files (bug report may follow) at the end of the backup I had to restore directories by choosing "set back to an earlier version" (retranslation from german "Auf frühere Version zurücksetzen") for one dirctory after another.

After a big directory (ca. 70 GB) deja-dup ends the restoring process with an error message: "The following files could not be restored. Please ensure that you have write premission for them." (retranslated from german translation)
Deja-dup did not tell something about too long path/filename.

Here are two examples from the list with 28 files (they are not directly in root but in the Documents-Folder inside the user directory):

'/MATERIAL/PHYSIK NAWI/Überblick zur DVD Relativitätstheorie und Gravitationswellen. Spannende Filme über eine 100 Jahre alte Theorie und ihre höchst aktuellen Anwendungen.pdf'

'/FALDERA/12-Physik/12.2 Quantenphysik des Lichts/04 -- Lichtelektrischer Effekt/Albert Einstein: Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt. In: Annalen der Physik. 322, Nr. 6, 1905 -- 1905_17_132-148.pdf'

Because restoring my backups to an unencrypted home directory worked before, it could be related to the encrypted user-directory.

Thanks for all effort and
kindest regards

$ lsb_release -rd
Description: Ubuntu 16.04.1 LTS
Release: 16.04

$ apt-cache policy deja-dup
deja-dup:
  Installiert: 34.2-0ubuntu1
  Installationskandidat: 34.2-0ubuntu1
  Versionstabelle:
 *** 34.2-0ubuntu1 500
        500 http://de.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: deja-dup 34.2-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-45.66-generic 4.4.21
Uname: Linux 4.4.0-45-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Sat Oct 22 20:30:22 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2016-10-21 (1 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
ProcEnviron:
 LANGUAGE=de_DE
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: deja-dup
UpgradeStatus: No upgrade log present (probably fresh install)

[Christian Herzberg (chrisch)]

I tried to restore a missing file with nautilus context menu "restore missing files".
Deja-dup showed the error message:
Fehler beim Erstellen des Ordners: Der Dateiname ist zu lang
(retranslation: error creating the folder: The filename is to long.)

Restoring the same file on another ubuntu-system without home encrytion works instead without any error message.

[Christian Herzberg (chrisch)]

I tried to copy file which was restored on the second system. Ubuntu/Nautilus on the second system copy the file without problems to an USB-Stick. On the first system with the encryted home directory ubuntu/nautilus reported an error:

Fehler beim Kopieren von »0x -- BodyPerccussion, ...tung Come and get it.pdf«.
Beim Kopieren der Datei nach /home/chrisch/Dokumente/FALDERA/10-Musik/10 -- Musik -- Stunden und Material von Ingo ist ein Fehler aufgetreten.
Fehler beim Öffnen der Datei »/home/chrisch/Dokumente/FALDERA/10-Musik/10 -- Musik -- Stunden und Material von Ingo/0x -- BodyPerccussion, Shut the door, Jesus is my salvation, Musicalsongs, Notenlehrer Gehördiktat rhythmisch und Schreibübung, Wdh und Erarbeitung Come and get it.pdf«: Der Dateiname ist zu lang

(retranslation: Error copying »0x -- BodyPerccussion, ...tung Come and get it.pdf«.
An error occured copying the file to /home/chrisch/Dokumente/FALDERA/10-Musik/10 -- Musik -- Stunden und Material von Ingo
Error opening the file »/home/chrisch/Dokumente/FALDERA/10-Musik/10 -- Musik -- Stunden und Material von Ingo/0x -- BodyPerccussion, Shut the door, Jesus is my salvation, Musicalsongs, Notenlehrer Gehördiktat rhythmisch und Schreibübung, Wdh und Erarbeitung Come and get it.pdf«: The filename is too long)

Expected Behavior:
I would expect that ubuntu/neutilus will give the option to rename the file (the same way you can give a new name to a file which filename is in the target directory) and an automated option to trim the filename.

And I would expect that deja-dup does the same and show a message afterwards.