subtree merging fails

Following the instructions here: https://git-scm.com/book/en/v1/Git-Tools-Subtree-Merging will lead to an error.

In particular, if the subtree is merged and then updated, this command that is supposed to update the local subtree fails with a fatal: refusing to merge unrelated histories error.

$ git merge --squash -s subtree --no-commit rack_branch

A workaround could be using the --allow-unrelated-histories option

$ git merge --squash --allow-unrelated-histories -s subtree --no-commit rack_branch

But this completely destroys my project by pushing the subtree contents into a completely irrelevant directory in my project (no in the subtree).

Any ideas??

https://github.com/git/git-scm.com/issues/896#issuecomment-277587626

Have you tried using (without -s subtree) -X subtree=path/to/add/subtree/at?

From the man page:

          subtree[=<path>]
               This option is a more advanced form of subtree
strategy, where the strategy
               makes a guess on how two trees must be shifted to match
with each other when
               merging. Instead, the specified path is prefixed (or
stripped from the
               beginning) to make the shape of two trees to match.

On Tue, Feb 7, 2017 at 2:16 AM, Stavros Liaskos <st.liaskos@gmail.com> wrote:

On Tue, Feb 07, 2017 at 08:59:06AM -0600, Samuel Lijin wrote:

I'm not 100% certain, but it's highly likely that the subtree=<prefix> argument needs to include a trailing slash "/" in the prefix, otherwise files will be named e.g. "fooREADME" instead of "foo/README" when prefix=foo.

These days I would steer users towards the "git-subtree" command in contrib/ so that users don't need to deal with these details. It handles all of this stuff for you.

https://github.com/git/git/blob/master/contrib/subtree/git-subtree.txt

https://github.com/git/git/tree/master/contrib/subtree

Updating the progit book to also mention git-subtree, in addition to the low-level methods, would probably be a good user-centric change.

@Samuel Lijin I tried now and I get: "merge: branch_name
- not something we can merge". Maybe that is something easy to fix but currently I am using a workaround script so I am not putting any more effort at this at the moment.

@David Aguilar That's true but the trailing slash is already there. This commands looks promising. An update would be GREAT!

FYI that's the script I am using to address this problem:

#!/bin/bash

function initial {
  if git remote | grep -q lisa_remote
  then
    echo "Subtree delete & update"
    git checkout lisa_branch
    git pull
    git checkout master
    git merge --squash -s subtree --no-commit lisa_branch
    git merge --squash --allow-unrelated-histories -s subtree
--no-commit lisa_branch
  else
    echo "Add subtree"
    git remote add lisa_remote git@xxxxxxxx:lisa/lisa.git
    git fetch lisa_remote
    git checkout -b lisa_branch lisa_remote/master
    git checkout master
    git read-tree --prefix=lisaSubTree/ -u lisa_branch
    gitrm
    git rm --cached -r lisaSubTree/.gitignore
    git rm --cached -r lisaSubTree/*
  fi
}
initial

On Tue, Feb 7, 2017 at 7:44 PM, David Aguilar <davvid@gmail.com> wrote: