Bug#703868: libav: Internal error: found 2 (choice -> promotion) mappings for a single choice.

[shirish शिरीष]

Source: libav
Version: 6:9.4-1
Severity: normal

Dear Maintainer,
        I was updating the system today and came across this :-

$ sudo aptitude install libswscale2=6:9.4-1 libswscale-dev=6:9.4-1
libavutil-dev=6:9.4-1 libavcodec-dev=6:9.4-1 libavutil52=6:9.4-1
libavformat-dev=6:9.4-1 libavformat54=6:9.4-1 -y
The following NEW packages will be installed:
  libavcodec-extra-54{ab}
The following packages will be upgraded:
  libavcodec-dev libavformat-dev libavformat54 libavutil-dev
libavutil52 libswscale-dev libswscale2
7 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 6,876 kB of archives. After unpacking 7,697 kB will be used.
The following packages have unmet dependencies:
 libavcodec54 : Conflicts: libavcodec-extra-54 but 6:9.4-1 is to be installed.
 libavcodec-extra-54 : Conflicts: libavcodec54 but 6:9.3-1 is installed.
Internal error: found 2 (choice -> promotion) mappings for a single choice.
Internal error: found 2 (choice -> promotion) mappings for a single choice.
Internal error: found 2 (choice -> promotion) mappings for a single choice.
Internal error: found 2 (choice -> promotion) mappings for a single choice.
The following actions will resolve these dependencies:

  Remove the following packages:
1)     libavcodec54

The following NEW packages will be installed:
  libavcodec-extra-54{a}
The following packages will be REMOVED:
  libavcodec54{a}
The following packages will be upgraded:
  libavcodec-dev libavformat-dev libavformat54 libavutil-dev
libavutil52 libswscale-dev libswscale2
7 packages upgraded, 1 newly installed, 1 to remove and 0 not upgraded.
Need to get 6,876 kB of archives. After unpacking 975 kB will be used.

While I don't understand all the implications of the above upgrade,
however I do understand that one of the packages is being removed
while the other is taking it's place. I didn't find anything in the
changelog as to why this is desirable. Also why it took one choice
when it says there are two choices.

Looking forward for more info. Maybe I did something wrong.

-- System Information:
Debian Release: 7.0
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable'), (10, 'unstable'), (1,
'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.2.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_IN.utf8, LC_CTYPE=en_IN.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

-- 
          Regards,
          Shirish Agarwal  शिरीष अग्रवाल
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