It is seemed to 813786 resolved bug you can see:
From: Julian Andres Klode <jak@debian.org>
To: 813786-close@bugs.debian.org
Subject: Bug#813786: fixed in apt 1.4~beta3
Date: Thu, 05 Jan 2017 21:03:45 +0000
But now problem is for local repository.
I install or update a packets on my local computer with Debian 64 8.6 Unstable through 2 stages.
At first, through apt-mirror (0.5.1-1 or 0.5.2-1) i update local repository on separated hard disk. At next, i install or update packets through apt, aptitude or synaptic from local repository. When i work in Debian Stable through apt (1.0.9.8.3), aptitude (0.6.11-1+b1) or synaptic (0.81.2) it is all right.
But if i use more higher versions all is worst. Now I use:
Testing:
apt (1.4~beta2)
aptitude (0.8.4-1)
synaptic (0.83+nmu1)
For example:
root@A1:/home/u1# apt update
Rec:1 file:/media/u1/DebRepo/deb-repo/mirror/mirror.mephi.ru/debian sid InRelease [209 kB]
Rec:1 file:/media/u1/DebRepo/deb-repo/mirror/mirror.mephi.ru/debian sid InRelease [209 kB]
Read package lists… Ready
Building dependency tree
Read status information… Ready
Can be updated 1 package. Run "apt list --upgradable" for the show.
N: Can't drop privileges for downloading as file
«/media/u1/DebRepo/deb-repo/mirror/mirror.mephi.ru/debian/dists/sid/InRelease» couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission non accordée).
synaptic (0.83+nmu1), when access to the local repository, issue such reports "Cannot be reset rights for download" and failing to access the repository.
Aptitude (0.8.4-1), when we update packets list (press button «u») it is showed
file:/media/u1/Debian/deb-repo/mirror/mirror.mephi.ru/debian sid/main Translation.ru [Error]
file not found — file:/media/u1/Debian/deb-repo/mirror/mirror.mephi.ru/debian/dists/sid/main/i18n/Translation-ru (2: file not found)
file:/media/u1/Debian/deb-repo/mirror/mirror.mephi.ru/debian sid/main [Ignored]
Unstable:
apt (1.4)
synaptic (0.84.2)
For example:
root@A1:~# apt update
Get:1 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid InRelease [231 kB]
Get:1 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid InRelease [231 kB]
Get:2 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/main amd64 Contents (deb) [34.4 MB]
Ign:2 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/main amd64 Contents (deb)
Get:3 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/contrib amd64 Contents (deb) [117 kB]
Ign:3 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/contrib amd64 Contents (deb)
Get:4 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/non-free amd64 Contents (deb) [839 kB]
Ign:4 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/non-free amd64 Contents (deb)
Get:2 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/main amd64 Contents (deb) [34.4 MB]
Ign:2 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/main amd64 Contents (deb)
Get:3 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/contrib amd64 Contents (deb) [117 kB]
Ign:3 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/contrib amd64 Contents (deb)
Get:4 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/non-free amd64 Contents (deb) [839 kB]
Get:2 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/main amd64 Contents (deb) [504 MB]
Ign:4 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/non-free amd64 Contents (deb)
Err:2 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/main amd64 Contents (deb)
File not found - /media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian/dists/sid/main/Contents-amd64 (2: No such file or directory)
Get:3 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/contrib amd64 Contents (deb) [1,501 kB]
Ign:3 file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian sid/contrib amd64 Contents (deb)
Reading package lists... Done
N: Download is performed unsandboxed as root as file '/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian/dists/sid/InRelease' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
E: Failed to fetch file:/media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian/dists/sid/main/Contents-amd64 File not found - /media/u1/DebRepo/DebianMirror/mirror/mirror.mephi.ru/debian/dists/sid/main/Contents-amd64 (2: No such file or directory)
E: Some index files failed to download. They have been ignored, or old ones used instead.
root@A1:~#
Can be updated 1 package. Run "apt list --upgradable" for the show.
N: Download is performed unsandboxed as root as file '/media/u1/Debian/deb-repo/mirror/mirror.mephi.ru/debian/dists/sid/InRelease' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission non accordée)
By the way, if in sources.list specify a remote repository over http, then everything works.
It seems that these programs can't work with «file://» access.