Re: [PATCH] docs: add filter-branch note about The BFG

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 18, 2013, 05:57 UTC
Message-ID: <xmqqr49ak8fi.fsf@gitster.dls.corp.google.com>
In-Reply-To: <CAFY1edaEZzDUuG9kopbAp9h2Frc2aLRKkjKMUnpSonML2xZN=A@mail.gmail.com>

Roberto Tyley <roberto.tyley@gmail.com> writes:

Show 10 quoted lines

> * The BFG takes advantage of multi-core machines, cleaning commit
> file-trees in parallel, which git-filter-branch currently does not do.
> * Any particular version of a file is cleaned exactly _once_. The BFG,
> unlike git-filter-branch, does not give you the opportunity to handle
> a file differently based on where or when it was committed within your
> history.
> * The link:http://rtyley.github.io/bfg-repo-cleaner/#examples[command-set]
> is much more restrictive than git-filter branch, and dedicated just to
> the tasks of removing unwanted data - e.g. `--strip-blobs-bigger-than
> 1M`.

I do not know offhand if the above formats well with AsciiDoc. You may have to do it like this:

* The first line of the bulletted paragraph is
  followed by the second and subsequent lines indented
  to align with the first one.

The first bullet point may be somewhat misleading, though. Nothing stops your script you use in filter-branch from processing blobs belonging to a single tree in parallel---the user just needs to do a bit more work to do so.

I think the second point is the most characteristic in BFG (and that is what allows easy parallelization of the filtering). Also, it cannot be stressed enough that the "removing unwanted contents" use case can take advantage of the "bad contents in a blob is bad, no matter where in the tree and when in the history the blob appears". That is what makes BFG particularly shine for the use case. Its design very much aligns the objective the use case wants to achieve.