Re: [PATCH v2] filter-branch: use printf instead of echo -e

[Michele Locati <michele@locati.it>]

Il 21/03/2018 22:50, Johannes Schindelin ha scritto:
> Hi Michele,
> 
> On Mon, 19 Mar 2018, Michele Locati wrote:
> 
>> [...]
>> -- 
>> 2.16.2.windows.1
> 
> Yaaaaay!
> 
> Out of curiosity: did the CONTRIBUTING.md file help that was recently
> turned into a guide how to contribute to Git (for Windows) by Derrick
> Stolee?

Well, no. Here's what led me here...

The people behind the concrete5 CMS asked support for improving the 
following procedure:

concrete5 is stored in
https://github.com/concrete5/concrete5
In order to make it installable with Composer (a PHP package manager), 
we need to extract its "/concrete" directory, and push the results to 
https://github.com/concrete5/concrete5-core
We previously used "git filter-branch --all" with this script:
https://github.com/concrete5/core_splitter/blob/70879e676b95160f7fc5d0ffc22b8f7420b0580b/bin/splitcore

That script is executed every time someone pushes concrete5/concrete5, 
and it took very long time (3~5 minutes).

I noticed on the git-filter-branch manual page that there's a 
"--state-branch", and it seemed quite interesting.
So, I asked in git@vger.kernel.org how to use it, and the author of that 
feature (Ian Campbell) told me to look at some code he wrote.
So, I wrote
https://github.com/concrete5/incremental-filter-branch
which wraps "git filter-branch --filter-state", and it's used in
https://github.com/concrete5/core_splitter/blob/99bbbcea1ab90572a04864ccb92327532ab6a42c/bin/splitcore
(it not yet in production: Korvin wants to be sure everything works well 
before adopting it)
The time required for the operation dropped from 3~5 minutes to ~10 
seconds ;)

While writing that script, I noticed a couple of things that could be 
improved in "git-filter-branch", so I submitted
https://marc.info/?l=git&m=152111905428554&w=2
(so that the script could run without problems if there's nothing to do)
and
https://marc.info/?l=git&m=152147095416175&w=2
(so that  --filter-state could be used on Mac and other non-Linux systems).
How did I learn how to submit to git? I searched for "git src", landed 
on https://github.com/git/git, read Documentation/SubmittingPatches and 
used git send-email.

And yes, all that on Windows (and WSL).


> 
> Ciao,
> Johannes

Ciao!

--
Michele