Re: [PATCH] Documentation: filter-branch env-filter example
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Feb 14, 2013, 20:29 UTC
- Message-ID
- <7vy5eqy6z3.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <511D3C33.6070902@hell.org.pl>
Tadeusz Andrzej Kadłubowski <yess@hell.org.pl> writes:
> filter-branch --env-filter example that shows how to change the email address > in all commits by a certain developer. > ---
Thanks. Sign-off?
Show 17 quoted lines
> Documentation/git-filter-branch.txt | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt > index dfd12c9..2664cec 100644 > --- a/Documentation/git-filter-branch.txt > +++ b/Documentation/git-filter-branch.txt > @@ -329,6 +329,19 @@ git filter-branch --msg-filter ' > ' HEAD~10..HEAD > -------------------------------------------------------- > > +You can modify committer/author personal information using `--env-filter`. > +For example, to update some developer's email address use this command: > + > +-------------------------------------------------------- > +git filter-branch --env-filter ' > + if [ $GIT_AUTHOR_EMAIL = john@old.example.com ]
Quote the variable in double-quotes, like this:
if [ "$GIT_AUTHOR_EMAIL" = john@old.example.com ]
Otherwise the comparison will break, if the e-mail part had a whitespace in it, or if it were empty, which is an example of a more likely situation where you would want to fix commits using a procedure like this, no?
But more on the example later...
Show 7 quoted lines
> + then > + GIT_AUTHOR_EMAIL=john@new.example.com > + fi > + export GIT_AUTHOR_EMAIL > +' -- --all > +-------------------------------------------------------- > +
I do not think an illustration of env-filter is a bad addition per-se, but the sample scenario is not a realistic one. No sane project should be encouraged to rewrite their entire history every time one of the contributors change his e-mail address. That is what the mailmap mechanism is for.
The only scenario that justifies use of the given sample I can think of is to rewrite the author and committer in an unpublished project because you noticed that you forgot to set user.name and user.email up before you created these commits correctly.
Taking all of the above, the added text may look more like this, I think:
The `--env-filter` can be used to modify committer and/or author identity. For example, if you found out that your commits have wrong identity of yours due to misconfigured user.email, you can make correction, before publishing the project, like this:
--------------------------------------------------------
git filter-branch --env-filter '
if test "$GIT_AUTHOR_EMAIL" = "root@localhost"
then
GIT_AUTHOR_EMAIL=yess@example.com
export GIT_AUTHOR_EMAIL
fi
if test "$GIT_COMMITTER_EMAIL" = "root@localhost"
then
GIT_COMMITTER_EMAIL=yess@example.com
export GIT_COMMITTER_EMAIL
fi
' -- --all
--------------------------------------------------------By the way, I left the "export" in; "git filter-branch --help" explicitly says that you need to re-export it. But I am not sure if they are necessary, especially after 3c730fab2cae (filter-branch: use git-sh-setup's ident parsing functions, 2012-10-18) by Peff, which added extra "export" to make sure all six identity variables are exported. After applying the above rewrite, we may want to do the following as a separate, follow-up patch.
Documentation/git-filter-branch.txt | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt index 8ebe999..066548e 100644 --- a/Documentation/git-filter-branch.txt +++ b/Documentation/git-filter-branch.txt @@ -83,8 +83,7 @@ OPTIONS This filter may be used if you only need to modify the environment in which the commit will be performed. Specifically, you might want to rewrite the author/committer name/email/time environment - variables (see linkgit:git-commit-tree[1] for details). Do not forget - to re-export the variables. + variables (see linkgit:git-commit-tree[1] for details). --tree-filter <command>:: This is the filter for rewriting the tree and its contents. @@ -340,12 +339,10 @@ git filter-branch --env-filter ' if test "$GIT_AUTHOR_EMAIL" = "root@localhost" then GIT_AUTHOR_EMAIL=yess@example.com - export GIT_AUTHOR_EMAIL fi if test "$GIT_COMMITTER_EMAIL" = "root@localhost" then GIT_COMMITTER_EMAIL=yess@example.com - export GIT_COMMITTER_EMAIL fi ' -- --all --------------------------------------------------------