llvm dev - Jul 2016 - [cfe-dev] [lldb-dev] Sequential ID Git hook

> El jun. 30, 2016, a las 19:31, Matthias Braun via cfe-dev <cfe-dev at
lists.llvm.org> escribió:
> 
> 
>> On Jun 30, 2016, at 4:14 PM, Renato Golin via llvm-dev <llvm-dev at
lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote:
>> 
>> 
>> On 30 Jun 2016 10:20 p.m., "Robinson, Paul" <paul.robinson
at sony.com <mailto:paul.robinson at sony.com>> wrote:
>> > We've since stopped creating the tags, and gotten used to not
having
>> > them.  We do the 'rev-list --count' trick which mainly
gets recorded as
>> > one component of the version number, and it has been working for
us.
>> 
>> Does that work for sub modules inside the umbrella project?
>> 
>> How can you trigger a hook in the umbrella project for commits inside
the sub modules?
>> 
> First: This is purely about generating sequential revision numbers, it does
not help setting up a server hook to update the submodule references in the meta
repository. The point I am trying to make here is that we only need to solve the
problem of updating the submodule references, and that generating sequential ID
numbers as an alternative to git hashes is no problem.
> 
> As far as I can see we need the following operations for sequential ID
numbers and they are all easy enough to perform with git on the client side:
> 
> 1. Produce revision number for current checkout (to use in tool --version
output):
> You can put something like
>   > echo "#define VERSION $(git rev-list --count HEAD)" >
version.h
> in your buildsystem
> 
> 2. Convert git hash to revision number:
>   git rev-list --count $HASH
> 
> 3. Convert revision number $NUM to git hash:
>   git rev-list HEAD | tail -n $NUM | head -n 1
I just want to point out another alternative that I often use in my projects: 
(Example from buildbot repo I had handy)

$ git describe
v0.9.0b8-579-ge06cac6

The format is "TAG-N-gREV", where TAG is the closest reachable git tag
in the past ("v0.9.0b8"), N is the relative number of revisions past
that tag (579), and REV is the short revision to make it unique and easy to
locate ("e06cac6", the 'g' is a literal character that
prefixes the revision). In other words, that "-579-" represents a
monotonically increasing value relative to the named tag and might serve your
purposes.

Jared

-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20160703/8917b170/attachment.html>

On 4 July 2016 at 06:01, NAKAMURA Takumi via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> "git-describe -t" works also for lw tags.
But it doesn't work if there are no tags, I just tested on LLVM and I get:

$ git describe
fatal: No names found, cannot describe anything.

Should be easy enough to create the tags on each branching point, though.

"describe" also seems to be available at least since Git 1.9, so it
should be pretty safe.

And since tagging *every* commit doesn't scale for long ranges, and
anything else will need scripting on the client side, I think we can
get rid *completely* of any server side hook, and let the client side
scripts deal with the output of "git describe".

Or am I just too optimistic?

cheers,
--renato