[Reproducible-builds] Bug#808120: diffoscope: Should use less memory

[Mike Hommey]

Source: diffoscope
Version: 43
Severity: wishlist

Dear Maintainer,

   * What led up to the situation?

Comparing
http://archive.mozilla.org/pub/firefox/try-builds/mh@glandium.org-393e224a2bfe01eb5537d3d5ffa486d92006c4f0/try-linux-debug/firefox-45.0a1.en-US.linux-i686.tar.bz2
with
https://queue.taskcluster.net/v1/task/HaDsgSx0RUKwV2fEltHhow/runs/0/artifacts/public/build/target.tar.bz2

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

I wanted a full report, so I did:

`diffoscope --html debug32.html firefox-45.0a1.en-US.linux-i686.tar.bz2 target.tar.bz2 --max-report-size 1000000000000 --max-diff-input-lines 10000000000`

   * What was the outcome of this action?

A 533KB HTML file that, considering its size, doesn't contain much differences.
Yet, while processing this, the diffoscope process (not its children readelf,
objdump or diff processes) sucked more than 4GB of memory. That tells me
something unexpectedly suboptimal is happening.

   * What outcome did you expect instead?

Less memory usage.


-- 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)