WEBVTT

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I'm here today to talk to you about
diffoscope

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and how you can use it as a better diff

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or for Quality Assurance, etc., things
like that.

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Moin!

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Apparently that's like a north german
thing to say "welcome".

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North german, north Denmark, Scandinavia,
that kind of thing, I'm told.

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People are shaking their head, so I'm
going to assume that's true.

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This is my first PC, an IBM 5155.

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Sometimes, when you rebooted it, it would
launch into, it would somehow revert

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from booting from the hard disk to booting
from a basic ROM,

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as in the programming language ROM.

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It was on my motherboard for some reason.

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So, randomly, you just get a chance to
program in basic and then,

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sometimes you wouldn't, I don't know why,
but… yeah.

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It's quite fun with this kind of clicky
keyboard, and that folded in

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and it was this kind of big desk thing.

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Anyway…

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This is my first Debian.

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At the time it was already old.

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What's this one? Is this Slink? 2.2?
Yeah.

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And this is when we had US and non-US,
so that's really dating if you remember that.

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This is my first contribution to Debian,
19th December 2006,

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sending a patch to lillypond which is kind
of interesting

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and the response was "Oh yeah, rock on,
many thanks. I'll upload this and

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it'll be landing to Etch".

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And this was super motivating because
Etch was just coming out and it was like

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"Great, I've got let one line of tiny patch
in a release. This is super cool."

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Thomas' response was super motivating.

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So, after that, like that Christmas
basically spent ???

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Debian webpages and stuff.

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Very well timed.

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That's kind of a good…

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You know, someone sends a patch, be like
"Cool, thanks"

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Like a little notice in the changelog.

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It was, you know, so stupid but…
Yeah, do that kind of thing.

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So, moving on.

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Why diffoscope?
Why did we write diffoscope?

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What's the background here?

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It comes from reproducible builds.

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The very quick outline is that once you
get the source code for free software,

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you download the source code for nginx
or whatever,

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pretty much everyone just runs binaries
on their servers or their systems.

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You know, "apt install bla", "yum install",
whatever.

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Android Playstore, whatever.

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Can you actually trust whether these two
things correspond with each other?

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You've gotten the source code, it looks
alright, and then you install this binary,

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yeah…

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Who generated that? Can you trust that
process?

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Can you trust who generated it?

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Even if you could trust them, could you
trust them not to be exploited? Etc.

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This is a big problem because you can
exploit a build farm and then

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obviously exploit all of that, you know,
a trojan into the build farm,

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so every single binary that comes out
is compromised.

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Kind of problematic.

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You could also target individual developers
machines,

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so I could go of to, say, your machine,
add a backdoor to it,

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so every binary that you give to friends
and things like that,

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are compromised in some way, stealing
your bitcoins or whatever.

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I can also turn up at your door
and blackmail you into producing

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software that has compromises or extra
features, shall we say,

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that don't exist in the source code.

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So what will happen there is that you'd
release your source

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and the binaries you produce have
this sort of backdoor that, you know,

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someone is forcing you into producing.

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So, you don't want to do that.

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Anyway

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enough of that.

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What you do for reproducible builds is you
ensure that every time you build

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a piece of software, you get an identical
result.

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Multiple people then compare their builds
and check whether they all get

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the same results

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and this means that an attacker must
either have infected everyone

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at the same time, or they haven't
infected anyone.

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The point here is that you have to ensure
that builds have identical results.

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Ok, great.

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So, we started the reproducible builds
project, etc.

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And we build 2 debs.

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Oh, I'm sorry about the colors there.

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You probably can't see that.

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That says "sha1sum a.deb b.deb".

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Anyway, we're comparing the sha1sums
of 2 binary Debian files.

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So, these two files differ.

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Ok, they're not reproducible.

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Why is that?

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So we run a diff on them.

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Yeah…

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So, what can we learn from this?

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Well, not very much, visibly they're
compressed so

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as soon as we see one change, we'll see
they would just cascade changes

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because that's how compression works.

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I guess we know it's a deb probably a ar
format file, not very useful.

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Ok, great so we're gonna have a look in

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We'll do a binary diff and ok, well…

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Again, that's not really telling us
very much

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with the diff there.

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Ok, great.

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??? one level in

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"ar x" is on the new maintainer thing,
"how you unpack a deb"

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Everyone remembers this, right?

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You unpack a.deb with "ar x" and you
do that to b.deb

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and then we diff the results of that.

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Ok, so…yeah, 7zip.

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Ok, compressed content, not very useful.

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Ok, so let's unpack the control.tar inside
these debs.

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And then we run diff on that.

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Still not really telling anything useful
about how to make this package reproducible

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So let's unpack the tar.xz into the tar.

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Inside that tar, there's a file called
md5sums and we start to see some differences

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between some files in these two debs.

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??? meaningful, so now
we have some idea that

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it has something to do with this
usr/bin/pmixer binary.

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Ok, interesting.

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We'll unzip that and then we do a diff on
pmixer itself.

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Now we're back into just binary
"globgoly" mode

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This isn't very helpful and this is taking
quite a while

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and if I remember correctly, Debian has
a lot of packages.

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So this might take a little while.

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So, basically, ??? mean

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I should build a better diff.

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That's not quite true, this is actually…

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It was lunar that started this project

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and it was called debbindiff, because
we wanted to diff

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binary Debian packages.

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So this is the initial commit, 2014.

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"The version is successfully able to report
differences in two .changes files.

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Not with much interesting details,
but it's a start."

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And it was a start.

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Fast forwarding… Oh, sorry about these
colors,

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I don't know if we can do anything about
the lights?

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Yeah?

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No?

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Allright, whatever…

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Basically, we're diffoscoping on…

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It works kind of diff does normally,

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you give it two files, it outputs
a unified diff.

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So "diffoscope a b", one file contains
the word "foo", one contains the word "bar".

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Nothing actually out of the ordinary.

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It's sort of colored by default, so that's
why you can't see it, but whatever.

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It supports archive formats, so if you
give it two tar files,

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if we then tar up our "a" file and
our "b" file into a a.tar and b.tar

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and then run diffoscope on those tar files

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we get this kind of, like, hierarchy here.

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So it's saying that there are differencies
between these files,

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in the file list they have different time
stamps, because I made them

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at different times,

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and here are the contents, so we got
"foo" there and "bar" there.

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So we can see the difference between them.

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Well, I can, I don't know if you can,
you get the slide there.

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If we gzip these tar files and then run
diffoscope on those gzip things,

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it'll say "ok, what we've done is unpack it
first, and here's the metadata

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about the gzip process",

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and inside that are a.tar and b.tar
from the previous slides.

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And then the "a" file and the "b" file.

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So, it's really going two levels deep
into this tar.gz file.

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That's pretty cool.

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And it's completely recursive, I think
it will actually blow out after, I think,

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1000 [levels].

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[light is turned down for the audience
to see the slides]

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I'll just bump back a bit, just in case.

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[Applause]

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Thank you.

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So that's the a and b files.

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We've tared them up and so I see
the hierarchy of foo and bar file layer.

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I've gziped them, so this is a gzip layer.

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Here's the tar layer and then there's
the files themselves.

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This is from a real .deb from the archive.

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Inside this .deb, there's a data.tar.xz
and in that xz file there's a data.tar

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and inside that tar file, there's a file
called aff and inside that

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there's a version string that is different.

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And that looks like a build date so we
probably know that if we went back

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to the source package, we could very
quickly work out,

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with get a very quick grep, work out
where this file is being generated from,

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the de_DE.aff file and then ???
probably quite obvious

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that it's using the current build time
and then we can just patch that, fix it etc.

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This is gone from two rather obscure
binary .debs all the way to the fix

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probably in about 5 minutes, and you can
probably send the patch in that time

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because it'd be quite quick.

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Without diffoscope here, without this sort
of recursive unpacking,

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you'd be just completely lost, you'd be
there with arx all day

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and working out which files are different
and trying to use xxd

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and this kind of nonsense.

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diffoscope's got some other things as well

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if you try to do reproducible packages
and things are varying just on

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the line ordering, we detect whether
a file differs only in the line ordering.

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So, here's file "a", "These lines are in
order".

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File "b" has "These order are in lines".

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It's very difficult to say, actually,
it's like one of these tongue twisters.

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Run diffoscope on these two and it says
it's got ordering differences only.

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That's interesting, so you probably need
to sort,

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you go all the way back to the source code,
work out very quickly,

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if you know it's just ordering differences
you just kind of know

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what the output's gonna be, you can
search for order in ???

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and you get the right files,

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??? sort in the right place,
BAM, send it patch of (???),

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everything is great.

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Oh, and send it to upstream as well
because you're good.

99:59:59.999 --> 99:59:59.999
It supports a lot more things.

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We've been showing the terminal
text output here.

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It's got a HTML output mode, which is
really useful in the hierarchal thing

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when it gets a bit more complicated.

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Instead of being laid on top of each other
like a unified diff,

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you get the diff on the left and the right
and you get sort of a nested

99:59:59.999 --> 99:59:59.999
thing inside with colors and lines and
you can link this and various things in it

99:59:59.999 --> 99:59:59.999
including bits of metadata here, other
bits here, what command you used.

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That's the HTML output.

99:59:59.999 --> 99:59:59.999
We also support a lot of file formats,
it's not just on text,

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it's about all of these, so let's quickly
run through some of them.

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You give it two Androip apk files which
are kind of like zips, but magic.

99:59:59.999 --> 99:59:59.999
It'll know how to compare them.

99:59:59.999 --> 99:59:59.999
There's like a Manifest file that needs
decoding.

99:59:59.999 --> 99:59:59.999
It supports Berkeley DB databases,

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Word documents, that's a Word document
with "a" and that's a Word document with "b"

99:59:59.999 --> 99:59:59.999
and it'll correctly do that.

99:59:59.999 --> 99:59:59.999
If you run that through diff normally,
that ??? be a binaly mess,

99:59:59.999 --> 99:59:59.999
so completely useless.

99:59:59.999 --> 99:59:59.999
E-books, there's epub, it also supports
mobi.

99:59:59.999 --> 99:59:59.999
So if you give it two epub files, it'll say
"They just differ in this date".

99:59:59.999 --> 99:59:59.999
Brilliant.

99:59:59.999 --> 99:59:59.999
Normally that will be completely useless
diff binary ???

99:59:59.999 --> 99:59:59.999
So you can be like "epub date, ok", grep
the source code for that,

99:59:59.999 --> 99:59:59.999
make a patch really quickly.

99:59:59.999 --> 99:59:59.999
Mono binaries, git repositories, why not?

99:59:59.999 --> 99:59:59.999
Gnumeric spreadsheets, ISO images.

99:59:59.999 --> 99:59:59.999
Oh yeah, ISO images is really cool.

99:59:59.999 --> 99:59:59.999
So, it'll basically unpack the ISO, then
inside that there might be a squashfs image

99:59:59.999 --> 99:59:59.999
then it'll completely go down to that and
work out any differences

99:59:59.999 --> 99:59:59.999
between the two contents in the ISO file,
including any metadata.

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This is on the squashfs metadata headers,
I think.

99:59:59.999 --> 99:59:59.999
But say inside that ISO, there was a file
that was a pdf, and inside that pdf was

99:59:59.999 --> 99:59:59.999
a ??? which varied,

99:59:59.999 --> 99:59:59.999
it will basically go all the way down
and say "yeah, it's actually here,

99:59:59.999 --> 99:59:59.999
in this ??? that the data differs."

99:59:59.999 --> 99:59:59.999
And that means you can just go again
all the way back to the source

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and say "ok, cool, we know how to fix
this quite quickly"

99:59:59.999 --> 99:59:59.999
And this is really valuable in getting
the recent Tails distribution reproducible

99:59:59.999 --> 99:59:59.999
so their ISOs are reproducible.

99:59:59.999 --> 99:59:59.999
If you build one and I build one, we get
the exact same one

99:59:59.999 --> 99:59:59.999
and that's kind of useful for something
like Tails where you would probably want to

99:59:59.999 --> 99:59:59.999
of all, there's a lot of projects that you
might want to compromise,

99:59:59.999 --> 99:59:59.999
you might want to go after that one,
because of the kind of people that are using it.

99:59:59.999 --> 99:59:59.999
We support comparing images, so this is
using ???

99:59:59.999 --> 99:59:59.999
and then just running that through diff.

99:59:59.999 --> 99:59:59.999
That is a linux penguin and that is
something else,

99:59:59.999 --> 99:59:59.999
I can't remember now. Oh, FT.

99:59:59.999 --> 99:59:59.999
It supports images.

99:59:59.999 --> 99:59:59.999
It supports JSON and pretty print,
so if you give it two JSON files

99:59:59.999 --> 99:59:59.999
one with key/value… it'll do a nice
diff of them.

99:59:59.999 --> 99:59:59.999
It will pretty print it first, before
doing the diff, so it'll actually give you

99:59:59.999 --> 99:59:59.999
something clean, otherwise I don't know
if you've ever diffed

99:59:59.999 --> 99:59:59.999
two very long JSON lines, if they differ
in the middle, you just get

99:59:59.999 --> 99:59:59.999
a huge long unified diff, but here it's
like "oh, just ??? things have changed"

99:59:59.999 --> 99:59:59.999
OpenDocument text formats,
Ogg audio files, because why not.

99:59:59.999 --> 99:59:59.999
tcpdump capture files, that's actually
quite useful.

99:59:59.999 --> 99:59:59.999
PDFs. That PDF says "Hello World" and
this PDF says "Hello sick sad world",

99:59:59.999 --> 99:59:59.999
I don't know why. ???
in the demo.

99:59:59.999 --> 99:59:59.999
Again, run that through normal diff
program… garbage.

99:59:59.999 --> 99:59:59.999
XML documents. Again, it'll pretty print
them so it's nice, actually nice do read.

99:59:59.999 --> 99:59:59.999
If you want to get started on diffoscope,
the very easiest and quickest way to do is

99:59:59.999 --> 99:59:59.999
fire up a web browser, try.diffoscope.org,
select your files, press Compare

99:59:59.999 --> 99:59:59.999
and it'll upload them and run diffoscope
with all the support for all the file formats

99:59:59.999 --> 99:59:59.999
in the cloud for you and give you a nice
HTML page that you can then link to people

99:59:59.999 --> 99:59:59.999
So that's the very quickest way to get
started.

99:59:59.999 --> 99:59:59.999
The next quickest way is to install
trydiffoscope and then you run that

99:59:59.999 --> 99:59:59.999
on two files and it'll basically do
the same thing,

99:59:59.999 --> 99:59:59.999
run it in the same cloud service as
trydiffoscope

99:59:59.999 --> 99:59:59.999
but it'll give you the result on the
command line or

99:59:59.999 --> 99:59:59.999
if you pass the webbrowser option, it will
give you an URL or load your webbrowser,

99:59:59.999 --> 99:59:59.999
I can't remember exactly which, with
the same results.

99:59:59.999 --> 99:59:59.999
This is 1kB of Python, nothing basically.

99:59:59.999 --> 99:59:59.999
That's the next easiest way.

99:59:59.999 --> 99:59:59.999
But you can then install diffoscope itself
on your own machine.

99:59:59.999 --> 99:59:59.999
I recommend not installing recommends
because all of those file formats

99:59:59.999 --> 99:59:59.999
might drag in extra things about
the whole of TeX,

99:59:59.999 --> 99:59:59.999
I think the whole of OpenOffice, whole
of Mono, whole Java…

99:59:59.999 --> 99:59:59.999
Android, yeah, quite big.

99:59:59.999 --> 99:59:59.999
I think there's another big one I can't
think of.

99:59:59.999 --> 99:59:59.999
They're all optional, and they all say
"By the way, I support TeX documents

99:59:59.999 --> 99:59:59.999
or whatever, Mono, whatever.

99:59:59.999 --> 99:59:59.999
But you need to install this package and
then you get full pretty printed support",

99:59:59.999 --> 99:59:59.999
And it'll tell you that when it's missing.

99:59:59.999 --> 99:59:59.999
So, if you just start with
--install-recommends disabled,

99:59:59.999 --> 99:59:59.999
right on your file, if it says
"please install this package, you can then

99:59:59.999 --> 99:59:59.999
install them as you go along, as you want"

99:59:59.999 --> 99:59:59.999
rather than installing everything.

99:59:59.999 --> 99:59:59.999
And then ??? and then works as before

99:59:59.999 --> 99:59:59.999
I you can improve all your own quality
assurance and debian packaging

99:59:59.999 --> 99:59:59.999
with different scope

99:59:59.999 --> 99:59:59.999
The biggest value here is not
necessary for reproducible builds

99:59:59.999 --> 99:59:59.999
It's for basically just seeing where you
do want to have a diff or expecting a diff

99:59:59.999 --> 99:59:59.999
and you are expecting a particularly type
of diff in a particularly way

99:59:59.999 --> 99:59:59.999
you can basically see those changes


99:59:59.999 --> 99:59:59.999
And if you build two debs normally and
... i'll try to demo in a second

99:59:59.999 --> 99:59:59.999
You build a deb with a patch applied you
can ??? see a diff on the source package

99:59:59.999 --> 99:59:59.999
But that's not very useful because the
binaries are going to end in the

99:59:59.999 --> 99:59:59.999
people machines. But if you run a diff on
the binary itself, did that change and

99:59:59.999 --> 99:59:59.999
really hit the binary, I think really ...
No..

99:59:59.999 --> 99:59:59.999
I just run through a very live demo of
course, so it's gonna fail ...

99:59:59.999 --> 99:59:59.999
Checkout some .... We'll get this 
libnetx-java

99:59:59.999 --> 99:59:59.999
We just build that once

99:59:59.999 --> 99:59:59.999
Lets say we are on security team and

99:59:59.999 --> 99:59:59.999
want to apply a patch, and we want to be
really sure because we are to push it out

99:59:59.999 --> 99:59:59.999
to all our users

99:59:59.999 --> 99:59:59.999
First we will make a changelog

99:59:59.999 --> 99:59:59.999
Closing a bug

99:59:59.999 --> 99:59:59.999
Find some java file to change

99:59:59.999 --> 99:59:59.999
Let's pretend we have a real patch

99:59:59.999 --> 99:59:59.999
Let's replace that equals equals,
say that was the fix

99:59:59.999 --> 99:59:59.999
So that's the patch from upstream

99:59:59.999 --> 99:59:59.999
Upstream blast patch

99:59:59.999 --> 99:59:59.999
When we build this what we wanna see is
just that change in the file

99:59:59.999 --> 99:59:59.999
we wanna see any nonsense changes of 
extended ??? but we also definitely want

99:59:59.999 --> 99:59:59.999
to see that change, cause if our binary as
for security reasons don't have that change

99:59:59.999 --> 99:59:59.999
the we aren't fixing people machines,
they will issue a DSA ??? installed, saying

99:59:59.999 --> 99:59:59.999
And you should do proper testing as well
at multiple levels

99:59:59.999 --> 99:59:59.999
I will build that again

99:59:59.999 --> 99:59:59.999
So we wanna diff the original one

99:59:59.999 --> 99:59:59.999
We wanna diff that one with a fake 
security one

99:59:59.999 --> 99:59:59.999
You see on the progress bar 100%
1- there are diferences (there should be

99:59:59.999 --> 99:59:59.999
diferences)
Lets see what that diferences are

99:59:59.999 --> 99:59:59.999
in our web browser, its a nice html output

99:59:59.999 --> 99:59:59.999
Let have a look.
Are we seeing what we wanna see?

99:59:59.999 --> 99:59:59.999
There are some chances in the data ta, we
kind of expect that

99:59:59.999 --> 99:59:59.999
Whats changed in our control file?
Well the version changed,we wanted that

99:59:59.999 --> 99:59:59.999
to change. Perfect

99:59:59.999 --> 99:59:59.999
And its changed to ???
That's what we wanna see

99:59:59.999 --> 99:59:59.999
No other changes here so there was no 
weird control or in magic going on

99:59:59.999 --> 99:59:59.999
In our data tar the color of the timestamp
changes, we will ignore these for now

99:59:59.999 --> 99:59:59.999
The changelog has changed, well I hope so
because I have changed that entry


99:59:59.999 --> 99:59:59.999
Here is where we going to start seeing
We are going to see the changing in the

99:59:59.999 --> 99:59:59.999
jar file which is the java class, java
compile archive format

99:59:59.999 --> 99:59:59.999
We are seeing some meaningless timestamp
changes but we can ignore those

99:59:59.999 --> 99:59:59.999
??? cause its just metadata maybe

99:59:59.999 --> 99:59:59.999
Ok part of a class, so if you can see here
it's basically a de-compilation of the

99:59:59.999 --> 99:59:59.999
java file itself and it's basically saying
"oh I use to say if now and if not now"


99:59:59.999 --> 99:59:59.999
So these are the actual byte java
byte code instructions and whats really

99:59:59.999 --> 99:59:59.999
And what is really ??? here
its that nothing else has changed


99:59:59.999 --> 99:59:59.999
We were just expecting that change between
the two op codes, of if now elseif not not now

99:59:59.999 --> 99:59:59.999
which is good cause its like it hasn't made
any code changes but also crucial we can

99:59:59.999 --> 99:59:59.999
see that it has actually made a change
to the code.

99:59:59.999 --> 99:59:59.999
For example its wasn't use some cached
version or something like that

99:59:59.999 --> 99:59:59.999
This is really useful

99:59:59.999 --> 99:59:59.999
And just running a naif diff wouldn't
give that of course, because it would just

99:59:59.999 --> 99:59:59.999
come with binary garbage
And just seeing the diff had changed again

99:59:59.999 --> 99:59:59.999
??? be told you anything, because all of the
change would have changed as well

99:59:59.999 --> 99:59:59.999
So its like well yes it's diferent

99:59:59.999 --> 99:59:59.999
The meaningful change there it's
what actually fixes the "floor"

99:59:59.999 --> 99:59:59.999
??? but we know it's there

99:59:59.999 --> 99:59:59.999
That's kind of ??? 
Shifting this deb out I'll be quite

99:59:59.999 --> 99:59:59.999
confident, that this seemed like the
actual bug

99:59:59.999 --> 99:59:59.999
I've been quite confident pushing that out
because it's very minimal amount of changes

99:59:59.999 --> 99:59:59.999
you wanna do that for security reasons

99:59:59.999 --> 99:59:59.999
So this was the live demo

99:59:59.999 --> 99:59:59.999
The other one is seeing no changes
at all, so you can build once

99:59:59.999 --> 99:59:59.999
if you build a reproducible

99:59:59.999 --> 99:59:59.999
You can build once change your compiler
or change some other part of your toolchain

99:59:59.999 --> 99:59:59.999
Build it again and if you got the exact same
results, well great, that's want you intended

99:59:59.999 --> 99:59:59.999
You wanna see no changes when you change
some part of it

99:59:59.999 --> 99:59:59.999
And that is really useful, if there were
changes diffoscope will highlight them

99:59:59.999 --> 99:59:59.999
and show exactly why they had changed,
maybe some compile authorizations,

99:59:59.999 --> 99:59:59.999
maybe some other things as well

99:59:59.999 --> 99:59:59.999
So you can use it in both ways, when you
expect changes and when you don't expect

99:59:59.999 --> 99:59:59.999
changes, and if those match the expectations
diffoscope will tell you exactly why

99:59:59.999 --> 99:59:59.999
It's all ??? when other companies
are doing security releases

99:59:59.999 --> 99:59:59.999
naming no names whatsoever,
but they like to release patches as you

99:59:59.999 --> 99:59:59.999
know just a new firmware for your router

99:59:59.999 --> 99:59:59.999
Very large file system images,
you basically have no ideia what changed

99:59:59.999 --> 99:59:59.999
between these two files, again you ???
through diff completely useless

99:59:59.999 --> 99:59:59.999
You can start to unpack them with
??? and blah blah blah

99:59:59.999 --> 99:59:59.999
But they're probably sort of concatenated
cpio archives, so that's nonsense

99:59:59.999 --> 99:59:59.999
But diffoscope would just chew you those
and give you actually what the diferences

99:59:59.999 --> 99:59:59.999
is between these two files, and say
they changed this, they've removed or

99:59:59.999 --> 99:59:59.999
added some gpl license code or something
kind of interesting

99:59:59.999 --> 99:59:59.999
So its very useful for diffing those kind
binary blobs that come from various people

99:59:59.999 --> 99:59:59.999
So the current state of diffoscope,
the development is up and down

99:59:59.999 --> 99:59:59.999
It started around May 2014 something like that
A bunch of work here, that's is idle I think

99:59:59.999 --> 99:59:59.999
There are just for debconfs basically

99:59:59.999 --> 99:59:59.999
Anyway it's going up and down its kind
of interesting

99:59:59.999 --> 99:59:59.999
??? a lot of reproducible builds projects
of course, so every time we do a build


99:59:59.999 --> 99:59:59.999
on the ??? reproducible builds or
testing framework if we run diffoscope

99:59:59.999 --> 99:59:59.999
on the result, if it's reproducible it
just says , hey the file is the same

99:59:59.999 --> 99:59:59.999
But if not, we publish the diffoscopes of
all your packages that are unreproducible

99:59:59.999 --> 99:59:59.999
just you can just go there and be like
whats the diference between these two things

99:59:59.999 --> 99:59:59.999
I invested a lot of work optimizing
diffoscope, ??? rather perverse end square

99:59:59.999 --> 99:59:59.999
loops inside it. So i manage to cut down
some of the time here, cut down here

99:59:59.999 --> 99:59:59.999
That's been quite a few performances and 
enhancements over the past ...

99:59:59.999 --> 99:59:59.999
these are the git tags , this is version 80
and this is version 50 I just run the same

99:59:59.999 --> 99:59:59.999
benchmark across them all

99:59:59.999 --> 99:59:59.999
So they shows when I have introduced some
rather stupid code, embarrassing , but whatever

99:59:59.999 --> 99:59:59.999
???

99:59:59.999 --> 99:59:59.999
There's work been done right now,
on parallel processing, there's been

99:59:59.999 --> 99:59:59.999
quite a few attempts before, but adding it
it's kind of interesting and difficult

99:59:59.999 --> 99:59:59.999
Luckily we have a ??? student Liliana,
is she in the room? Is she hiding?

99:59:59.999 --> 99:59:59.999
She's here and she's been talking tomorrow
about her work on paralel processing in

99:59:59.999 --> 99:59:59.999
diffoscope and that will be amazing because
a lot of it is IO bound or waiting for Xtel

99:59:59.999 --> 99:59:59.999
processors with multiple cpu machines,
you mind as well just play well

99:59:59.999 --> 99:59:59.999
while as I stand waiting for the result
for a pdf to be unpacked I maybe as well

99:59:59.999 --> 99:59:59.999
be running on another cpu, I think we are
going to see some real performance wins

99:59:59.999 --> 99:59:59.999
as we do that paralell processing merge and
working and ???

99:59:59.999 --> 99:59:59.999
You can check out our website diffoscope.org
recently migrated to Salsa .... yeeaahhh

99:59:59.999 --> 99:59:59.999
And everything ??? reproducible is now on
Salsa, it's kind of cool

99:59:59.999 --> 99:59:59.999
That's quite recent...

99:59:59.999 --> 99:59:59.999
Thank you very muck, Danke shcön

99:59:59.999 --> 99:59:59.999
You got any questions?
About diffoscope?

99:59:59.999 --> 99:59:59.999
Thank you very much !

99:59:59.999 --> 99:59:59.999
Q: A buzz word question, can you diff containers
image formats?

99:59:59.999 --> 99:59:59.999
A: Depend which ones. So if they are just
directory, then yes, because is just a directory

99:59:59.999 --> 99:59:59.999
Do you have particullary in mind? Like docker?

99:59:59.999 --> 99:59:59.999
Yes, there's docker and then there's old
CI, I believe is the standard one

99:59:59.999 --> 99:59:59.999
And that could make a buzz word complaint


99:59:59.999 --> 99:59:59.999
Ah ok we were all about buzz words

99:59:59.999 --> 99:59:59.999
Probable diffoscope block change as well

99:59:59.999 --> 99:59:59.999
And then run diffoscope on connectors and
see the difference between updates of your

99:59:59.999 --> 99:59:59.999
container images

99:59:59.999 --> 99:59:59.999
BAM ... solved
Where do I invest?

99:59:59.999 --> 99:59:59.999
I wasn't aware that OCI ... that's is how it's
called? No it doesn't support that right now

99:59:59.999 --> 99:59:59.999
But it wouldn't be too difficult, presuming
are tools to unpack it and as soon we have

99:59:59.999 --> 99:59:59.999
a tool to unpack it, it can then just go
to that, there is a wishing list tool box

99:59:59.999 --> 99:59:59.999
for docker containers to the point were
I think it would be really nice if you

99:59:59.999 --> 99:59:59.999
could just give it, say, two images names
or whatever the noun is

99:59:59.999 --> 99:59:59.999
So you can say "please diff these two
docker images that are available" and

99:59:59.999 --> 99:59:59.999
it can look at your local thing and do 
a diff on them, currently it's not

99:59:59.999 --> 99:59:59.999
supported, but there is an open wishlist
bug.

99:59:59.999 --> 99:59:59.999
Q: Shouldn't any company that releases
binaries, be interested in supporting

99:59:59.999 --> 99:59:59.999
diffoscope and using it?

99:59:59.999 --> 99:59:59.999
A1: Basically when companies release binaries they are not interested in users seeing diferences...

99:59:59.999 --> 99:59:59.999
A2: Yes, I'm surprised that actually the
docker bug was only opened two months ago

99:59:59.999 --> 99:59:59.999
and hasn't been more interest on diffing
container images, but if you like to open

99:59:59.999 --> 99:59:59.999
one for OCI that will be very appreciated,
and we can get on to that, that would be

99:59:59.999 --> 99:59:59.999
great.

99:59:59.999 --> 99:59:59.999
I was looking the page for OCI, it says
it's based on docker basically, so

99:59:59.999 --> 99:59:59.999
once you get OCI for free, you would
sort it out for docker, if you're lucky

99:59:59.999 --> 99:59:59.999
The OCI image formaters, they wrote out
on docker images

99:59:59.999 --> 99:59:59.999
Ok we will sort that out, and it seems like
we're using a docker more and more

99:59:59.999 --> 99:59:59.999
on debian

99:59:59.999 --> 99:59:59.999
Any other questions?

99:59:59.999 --> 99:59:59.999
Q: Out of curiosity, which ??? are you using
inside? Are you using some bio-informatics

99:59:59.999 --> 99:59:59.999
on ??? to diff trees efficiently?

99:59:59.999 --> 99:59:59.999
A: No it's really naif, all it does is run
normal diff, the normal diff tools, but

99:59:59.999 --> 99:59:59.999
it will try to identify files and unpack
first, so use the file utility identifier

99:59:59.999 --> 99:59:59.999
thing that says its a pdf , and try to
unpack it first, he doesn't do any clever

99:59:59.999 --> 99:59:59.999
matching. The clever matching that he does
do is fuzzy matching as well, so if just

99:59:59.999 --> 99:59:59.999
rename a directory between two inside a 
container, he will say , yeah there a

99:59:59.999 --> 99:59:59.999
massive match between this two files,
and things like that. So that's kind of

99:59:59.999 --> 99:59:59.999
useful. ??? it's not so that clever, which
is kind of what you want , cause if it's

99:59:59.999 --> 99:59:59.999
too clever it would start to be a little
opaque ...

99:59:59.999 --> 99:59:59.999
I personally like dumb tools.

99:59:59.999 --> 99:59:59.999
Q: So one question to you is whether,
if you wanna do a release to stable or

99:59:59.999 --> 99:59:59.999
something like that, you can ask for the
debdiff, I'm wandering if anyone

99:59:59.999 --> 99:59:59.999
I mean I remember doing that myself
I've been submitting diffoscope output

99:59:59.999 --> 99:59:59.999
as well, because is just more readable and
useful. so I'm not sure if anyone have any

99:59:59.999 --> 99:59:59.999
objection to people asking for those.


99:59:59.999 --> 99:59:59.999
I'll propose that to the release team
see what they say

99:59:59.999 --> 99:59:59.999
Thank you very much, 
any further questions?

99:59:59.999 --> 99:59:59.999
[Applause]