678088 - Use tools from an hg repository

Status: RESOLVED WONTFIX

(Release Engineering :: General, defect, P5)

Description

[Rafael Ávila de Espíndola (:espindola) (not reading bugmail)]

Chris asked if I had any ideas for making it easier to test changes to a compiler. The problem is a bit more general, it is hard to test changes to any tools we use during a build.

A solution I have seen being used before that worked *really* well was having the compiler be checked in the main repository. The analogous for us would be to have a tools/gcc and a tools/python for example.

Some benefits are:

*) With the tools being versioned with the code, we can insist that two builds should produce *identical* binaries. One year from now I would be able to check current code, build it an know the the produced dmg has the same md5 as one created "back in the day".

*) Testing new tools is just like testing new code: push to try.

*) Checking new tools is just like checking new code: push to m-c/m-i

The implementation I have seem of this used p4 and worked well because of p4's views lets that people not working on the tools avoid checking them out.

Jeff suggested that a way to do this with hg would be to have a mozilla-tools hg repo where we check in the versions of gcc/python/gold/etc that we use. In m-c we check only a rev number.

Testing a new tools is almost as convenient, just check it in mozilla-tools and push to try a change that updates the rev number.

Comment 1

[Aki Sasaki (not active)]

Cloning an hg repo means we clone the entire history, which makes hg a bad vcs for checking in large binary files.

CVS is, for all its faults, a much better option here, as you can check out a single directory and only get one copy of the binaries on disk.

Subversion is a slightly less ideal option, as you can check out a directory and only get two copies of the binaries on disk.

Supporting cvs or svn on our build machines is not on our radar at all.

Comment 2

[Chris AtLee [:catlee]]

git does shallow clones

another option is to use http to get the specific revision of a tool from hgweb

Comment 3

[Rafael Ávila de Espíndola (:espindola) (not reading bugmail)]

We will do bug 683975 instead.