Re: [BUG] rewriting history with filter-branch --commit-filter

On Wed, Aug 20, 2014 at 10:16:11AM +0200, Davide Fiorentino wrote:

I was in the need to rewrite author name and email and commit date for a single commit and I guess I found a bug.
I run this git-filter script

$ git filter-branch --commit-filter ‘
    if [ "$GIT_COMMIT"="9cfca27" ]; 
        then GIT_AUTHOR_NAME=“Michelle”; 
            GIT_AUTHOR_EMAIL=“michelle@email.com”; 
            GIT_AUTHOR_DATE="2009-12-31T23:59:59”; 
            git commit-tree "$@“; 
        else 
            git commit-tree "$@“;
    fi' HEAD

and found that all history was rewritten as if “Michelle” not only commit 9cfca27.

The filter snippets you provide to filter-branch are shell script. The
`[` command (aka `test`) is just another shell command, and follows the
usual whitespace splitting rules. In your command:

  [ "$GIT_COMMIT"="9cfca27" ]

it sees only one single argument, all concatenated together. A single
argument given to `test` is the same as `test -n`: it tells you whether
the string is empty, so this conditional is always true. You wanted:

  [ "$GIT_COMMIT" = "9cfca27" ]

instead. The whitespace makes the "=" a separate argument, and the
command knows it's an operator. You should also use the full commit id,
as that is what will be in $GIT_COMMIT.

-Peff