[Reproducible-builds] Bug#808199: diffoscope: Weird line numbering in diff output

[Mike Hommey]

Source: diffoscope
Version: 43
Severity: normal

Dear Maintainer,

   * What led up to the situation?

Comparing
https://queue.taskcluster.net/v1/task/FEXzanIjQKW_dBmv3ZmBJQ/runs/0/artifacts/public/build/target.tar.bz2
with
https://queue.taskcluster.net/v1/task/HqZ2DuHYRJ6kR2_P8Rc7Ig/runs/0/artifacts/public/build/target.tar.bz2

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

`diffoscope --html out.html target.tar.bz2 target.tar.bz2.1`

   * What was the outcome of this action?

The HTML output line numbering on the diff is weird. Specifically, it looks
like (simplified):

1 firefox/                        1 firefox/
2 firefox/libnssdbm3.chk          2 firefox/browser/
3 firefox/libfreebl3.chk          3 firefox/browser/omni.ja
4 firefox/libnssdbm3.so           4 firefox/browser/extensions/
5 firefox/crashreporter           5 firefox/browser/extensions/{972ce4c6-7e08-4474-a285-3208198ce6fd}.xpi
6 firefox/libnss3.so              6
7 firefox/firefox-bin             7
...                               ...

Lines 1 to 5 are yellow, 6 and 7 red.

The weird thing about the numbering is that there are numbers on the right hand
side for lines that were removed. Interestingly, there is no number for line
72, which is also a removed line.

The same problem shows up for added lines.

   * What outcome did you expect instead?

No numbers for added/removed lines in the part where there were no lines
originally



-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.2.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=ja_JP.UTF-8, LC_CTYPE=ja_JP.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)