[Reproducible-builds] [Debian Wiki] Update of "ReproducibleBuilds/MysteryByteIncrementInJarFiles" by HansChristophSteiner

[Lunar]

Debian Wiki:
> The "ReproducibleBuilds/MysteryByteIncrementInJarFiles" page has been changed by HansChristophSteiner:
> https://wiki.debian.org/ReproducibleBuilds/MysteryByteIncrementInJarFiles
> 
> New page:
> = mystery byte increments in jar format =
> 
> I've been working on reproducible jars, and I have fixed the
> timestamps by running the builds using `faketime`.  Now the contents
> of the jars are exactly the same when I unzip them, including the
> timestamps, but the jars themselves do not have the same hash.  Using
> `vbindiff`, I can see a smattering of bytes that are different, with
> almost always the same pattern: one build's byte will be +1 from the
> others, i.e. one has 98 and the other has 99, or 56 and 57.  It seems
> that this byte is some kind of separator between class names.

Is this a relevant issue for Debian? Using sortjar or
strip-nondeterminism in the build process makes faketime unneeded, but
it should also takes care of file ordering and these weird bytes.

The other options I can think of to solve jar related issues is to patch
all tools building jar.

-- 
Lunar                                .''`. 
lunar at debian.org                    : :Ⓐ  :  # apt-get install anarchism
                                    `. `'` 
                                      `-   
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