On 26 April 2010 11:38, Jonathan Nieder <jrnieder@xxxxxxxxx> wrote: > Hi Paul, > > Paul Richards wrote: > >> Is it possible to edit an old commit object and only alter the ID of >> the parent commit but otherwise leave all the other information intact >> (tree, message, authors, date, etc). >> >> I'd expect such a command to return the new hash of the modified commit. > > The standard answer to this question is to say “use grafts and > filter-branch”. The git-filter-branch(1) man page explains this > approach. It is very powerful, but sometimes I do not want to have > that much power. > > So I will tell a secret: in the scenarios when I wanted something like > this (actually, what I have occasionally wanted is to transform a > single-parent commit into a merge), I did something like the following: > > $ git cat-file commit $rev > tree dcd2cc4b76f8756423f5c1ab7d2c62d458a8b15f > parent 5f1e6d9ce35e212708f9adc55e6b9a7e0d296df4 > author Will Palmer <wmpalmer@xxxxxxxxx> 1272275407 -0500 > committer Jonathan Nieder <jrnieder@xxxxxxxxx> 1272275443 -0500 > > pretty: Respect --abbrev option > > Prior to this, the output of git log -1 --format=%h was always 7 > characters long, without regard to whether --abbrev had been passed. > > Signed-off-by: Will Palmer <wmpalmer@xxxxxxxxx> > Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx> > $ git cat-file commit $rev >tmp > $ sed -i -e "s/parent .*/parent $(git rev-parse othercommit)/" tmp > $ git hash-object -t commit -w tmp > ca55c560685284ac6d121939b2cd881f426e7074 > > Easy. Still, I would be happy to see this packaged in a command, so I > could recommend it in combination with ‘git replace’ to people who are > scared of sed. > > Thanks for bringing it up. > Jonathan > Thanks, this looks perfect. I knew about "cat-file", but "hash-object" was the missing command for me here. :) -- Paul Richards -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html