Package libc6:amd64 not installed about deb2snap

[bladernr]

Going to suggest this is not just an AMD64 thing...

I have built deb2snap within a pbuilder armhf environment just as nobuto-m did in the first issue he raised. I then installed isc-dhcp-server and attempted to build a snap from that.

Instead, I get an error like the one nobuto-m saw, only for the armhf port of libc6:

root@klaatu:/deb2snap# ./deb2snap dhcpd
Package libc6:armhf not installed

And likewise, it is installed:

root@klaatu:/deb2snap# apt-cache policy libc6:armhf
libc6:
  Installed: 2.21-0ubuntu4
  Candidate: 2.21-0ubuntu4
  Version table:
 *** 2.21-0ubuntu4 0
        500 http://ports.ubuntu.com/ vivid/main armhf Packages
        100 /var/lib/dpkg/status

[bladernr]

Removing the try/except around the addDeps() stuff results in this trace from apt.cache:

root@klaatu:/deb2snap/tools# ./dep-tree libc6:armhf
Adding Deps for libc6:armhf
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/apt/cache.py", line 198, in getitem
return self._weakref[key]
File "/usr/lib/python3.4/weakref.py", line 125, in getitem
o = self.datakey
KeyError: 'libc6:armhf'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "./dep-tree", line 76, in
addDeps(args.packages)
File "./dep-tree", line 56, in addDeps
installedPkg = cache[p].installed
File "/usr/lib/python3/dist-packages/apt/cache.py", line 205, in getitem
raise KeyError('The cache has no package named %r' % key)
KeyError: "The cache has no package named 'libc6:armhf'"

[bladernr]

Ok, it's because the packages refer to libc6:ARCH where apt cache actually just refers to it as libc6, which is, I think, exactly what nobuto-m mentioned in the comment he removed:

In [5]: cache['vim'].installed
Out[5]: <Version: package:'vim' version:'2:7.4.052-1ubuntu3'>

In [7]: cache['libc6:amd64'].installed
Out[7]: <Version: package:'libc6' version:'2.19-0ubuntu6.6'>

And leaving $ARCH off the name still works, at least in this instance:\

In [8]: cache['libc6'].installed
Out[8]: <Version: package:'libc6' version:'2.19-0ubuntu6.6'>

[bladernr]

FWIW, I fired up python3 in that environment and generated the trace directly:
(Note: this is in a Vivid armhf pbuilder environment on a Trusty amd64 host)

Python 3.4.3 (default, Mar 26 2015, 23:09:09) 
[GCC 4.9.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import apt
>>> cache = apt.Cache()
>>> cache['libc6:armhf'].installed
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 198, in __getitem__
    return self._weakref[key]
  File "/usr/lib/python3.4/weakref.py", line 125, in __getitem__
    o = self.data[key]()
KeyError: 'libc6:armhf'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3/dist-packages/apt/cache.py", line 205, in __getitem__
    raise KeyError('The cache has no package named %r' % key)
KeyError: "The cache has no package named 'libc6:armhf'"
>>> 

And then tried again with no arch:

>>> cache['libc6'].installed
<Version: package:'libc6' version:'2.21-0ubuntu4'>

[mikix]

OK, try now. I think all the systems I tried it on were multi-arch-enabled ones. I think it was failing on single-arch systems. Hopefully my code change will help there.

[bladernr]

Yep, as discussed on IRC, it builds now on my RPi. Thanks a lot! One suggestion for Launchpad though, if you end up packaging this, you need to add the following at a minimum as dependencies:

make (the instructions list cmake, but at least on some images like the Docker Ubuntu image you turned me on to, make is not installed).

dh-exec (will also pull in debhelper and some others that may also not be installed on some build systems initially).

Of course, that only applies if you are packaging this as a deb, thus far, I've only pulled the bzr and github trees and built from scratch.

[anthonywong]

On amd64, runs 'sudo dpkg --add-architecture i386'. This fixes for me.