5 ms·

Took me a while (after reading through the reply, to no avail) to figure out what this refers to. Here's the feature this is referring to: $ apt-get moo

by smcl 10y ago

Took me a while (after reading through the reply, to no avail) to figure out what this refers to. Here's the feature this is referring to: $ apt-get moo (__) (oo) /------\/ / | || * /\---/\ ~~ ~~ ..."Have you mooed today?"... Edit: maybe not actually! Just found this too: $ aptitude moo There are no Easter Eggs in this program. $ aptitude -v moo There really are no Easter Eggs in this program.

simias 10y ago
I don't really understand what in this feature makes the build non-reproducible. Judging by the patch it's the call to time(NULL) that seems to be problematic, but I don't understand why.
- lamby 10y ago
  It doesn't; it makes anyone using the output...
- smcl 10y ago
  Yeh I only skimmed the patch but I presumed "reproducable build" referred to the actual binary, and the patch addresses runtime behaviour. Guess I'm missing something.
- karrotwaltz 10y ago
  From what I can read in patch file, it seems to be doing something different on April fools day.
- kr7 10y ago
  The output of "apt-get moo" changes on special days (4/1, 12/25, 8/16, 11/7, 2/18). So if another program was using "apt-get moo" in its build script, the build would not be reproducible. With the patch, the SOURCE_DATE_EPOCH environment variable can be set to make "apt-get moo" deterministic. I don't think anything actually uses "apt-get moo" in its build script. This kind of patch makes more sense for build tools like "ar" (static library creator). By default, "ar" injects a timestamp into the output file, so the binary is different each build. But, use the "D" flag and "ar" becomes deterministic.
  - rzzzt 10y ago
    The time-dependent part can be seen here: https://github.com/Debian/apt/blob/master/apt-private/private-moo.cc#L164 https://github.com/Debian/apt/blob/master/apt-private/privat...
    - kr7 10y ago
      There is a second part above too: https://github.com/Debian/apt/blob/master/apt-private/private-moo.cc#L33 https://github.com/Debian/apt/blob/master/apt-private/privat...
CroCroCro 10y ago
Keep adding more v.
- smcl 10y ago
  Yep it gets good - wasn't sure whether to spoil the fun or not :)
- paulddraper 10y ago
  > I got a fever! And the only prescription.. is more -v!
dabber 10y ago
try $ apt-get moo moo $ apt-get moo moo moo
TimWolla 10y ago
This is “documented” as well. apt-get has got Super Cow Powers and aptitude has not. $ apt-get apt 1.0.9.8.4 for amd64 compiled on Dec 11 2016 09:48:19 Usage: apt-get [options] command apt-get [options] install|remove pkg1 [pkg2 ...] apt-get [options] source pkg1 [pkg2 ...] … This APT has Super Cow Powers. $ aptitude --help aptitude 0.6.11 Usage: aptitude [-S fname] [-u|-i] aptitude [options] <action> ... … This aptitude does not have Super Cow Powers.
- deleted 10y ago
  [deleted]
mvo 10y ago
Try `aptitude -vv moo` :)
- ansgri 10y ago
  Thanks. A nice New Year's gift, to learn Super Cow Powers. Though talking about more -v's, I don't think Aptitude is written in Python, is it?
Gaelan 10y ago
I recall that aptitude has more messages for more v's.
dfc 10y ago
This is a patch for apt, it does not have anything to do with aptitude.

by smcl 10y ago

simias 10y ago

I don't really understand what in this feature makes the build non-reproducible. Judging by the patch it's the call to time(NULL) that seems to be problematic, but I don't understand why.

lamby 10y ago
It doesn't; it makes anyone using the output...
smcl 10y ago
Yeh I only skimmed the patch but I presumed "reproducable build" referred to the actual binary, and the patch addresses runtime behaviour. Guess I'm missing something.
karrotwaltz 10y ago
From what I can read in patch file, it seems to be doing something different on April fools day.
kr7 10y ago
The output of "apt-get moo" changes on special days (4/1, 12/25, 8/16, 11/7, 2/18). So if another program was using "apt-get moo" in its build script, the build would not be reproducible. With the patch, the SOURCE_DATE_EPOCH environment variable can be set to make "apt-get moo" deterministic. I don't think anything actually uses "apt-get moo" in its build script. This kind of patch makes more sense for build tools like "ar" (static library creator). By default, "ar" injects a timestamp into the output file, so the binary is different each build. But, use the "D" flag and "ar" becomes deterministic.
- rzzzt 10y ago
  The time-dependent part can be seen here: https://github.com/Debian/apt/blob/master/apt-private/private-moo.cc#L164 https://github.com/Debian/apt/blob/master/apt-private/privat...
  - kr7 10y ago
    There is a second part above too: https://github.com/Debian/apt/blob/master/apt-private/private-moo.cc#L33 https://github.com/Debian/apt/blob/master/apt-private/privat...

CroCroCro 10y ago

Keep adding more v.

smcl 10y ago
Yep it gets good - wasn't sure whether to spoil the fun or not :)
paulddraper 10y ago
> I got a fever! And the only prescription.. is more -v!

dabber 10y ago

try $ apt-get moo moo $ apt-get moo moo moo

TimWolla 10y ago

This is “documented” as well. apt-get has got Super Cow Powers and aptitude has not. $ apt-get apt 1.0.9.8.4 for amd64 compiled on Dec 11 2016 09:48:19 Usage: apt-get [options] command apt-get [options] install|remove pkg1 [pkg2 ...] apt-get [options] source pkg1 [pkg2 ...] … This APT has Super Cow Powers. $ aptitude --help aptitude 0.6.11 Usage: aptitude [-S fname] [-u|-i] aptitude [options] <action> ... … This aptitude does not have Super Cow Powers.

deleted 10y ago
[deleted]

mvo 10y ago

Try `aptitude -vv moo` :)

ansgri 10y ago
Thanks. A nice New Year's gift, to learn Super Cow Powers. Though talking about more -v's, I don't think Aptitude is written in Python, is it?

Gaelan 10y ago

I recall that aptitude has more messages for more v's.

dfc 10y ago

This is a patch for apt, it does not have anything to do with aptitude.