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I've been using the git subtree extension (https://github.com/apenwarr/git-subtree) . I use "--squash" to make the log of main project clean, my steps like this:

  1. add lib into main project

    git subtree add -P sub/libdir --squash lib_remote master

  2. get update from lib

    git subtree pull -P sub/libdir --squash lib_remote master

  3. push changes to lib_remote

    git subtree push -P sub/libdir --squash lib_remote master

It works very well for me(both main project and lib, have a history make good sense). The problem is the time of git subtree push, becomes longer and longer.

My purpose of using git-subtree is almost the same with Screndib, who asked git-subtree is not retaining history so I cannot push subtree changes, how can I fix this/avoid this issue in the future?

I guess, when using --squash, every time to process a push , git subtree needs to search the whole history since the "subtree add".

How can I reduce the time of subtree push? Or make it work more effective, rather than the whole history, only process changes since last git subtree push(or pull)?

Anthony Mastrean
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Megodno
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  • Note: as [mentioned here](http://stackoverflow.com/a/30441980/6309) (Git 2.5+, Q2 2015), `--squash` is not available for `git subtree push` – VonC May 25 '15 at 16:06
  • Does this answer your question? [How can I reduce the ever-increasing time to push a subtree?](https://stackoverflow.com/questions/16134975/how-can-i-reduce-the-ever-increasing-time-to-push-a-subtree) – Anthony Mastrean Feb 27 '20 at 18:53

2 Answers2

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I assume "lib_remote" in your code menas the url of the remote lib repo not a branch in your current repo? Both remote repo url and branch in your current repo are working.

I see you were using git subtree add to add the remote lib as subtree and then you just using git subtree push to push the changes.

It is better to do a git subtree split operation to split the subtree changes to a seperate branch in your curent repo before the push operation, then push the splited branch to the remote repo and keep this splited branch existed, every time before the pushing, do a git subtree split operation again, this will build the history of the subtree form the point you last splited, it will be much faster. Otherwise, without this split just like you did, git subtreee has to build the history of the subree from the point you added, as long as the subtree commits growing,the time of the building will get longer and longer.

If you are not use --squash while adding, you can consider using --rejoin while you spliting, this will be much faster.

So, the step should be the following.

  1. add lib into main project

    git subtree add -P sub/libdir --squash lib_remote_url master

  2. get update from lib

    git subtree pull -P sub/libdir --squash lib_remote_url master

  3. split the subtree changes to a seperate branch

    git subtree split -P sub/libdir -b lib_remote_branch

  4. push changes to lib_remote

    git push lib_remote_url lib_remote_branch:master

Keep the lib_remote_branch existed and redo the step 3 and step 4 when next time push.

weynhamz
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    Thanks for the attention, but I failed to make it work. Here is the problem: do the step 3 and step 4, have some another commits, then do the step 3 again. The time still get longer. Even after a split, subtree seems still process the whole history since "add". Use --rejoin instead of --squash , this should work. But I really do not want the whole history of sublib merge into the main project, that will make it is very hard to get any sence out from gitk of the main project. I follow the exact steps as your description, may I do sth wrong? – Megodno Mar 13 '12 at 08:56
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    storing it in a seperate branch will not fix the issue at all – owagh Apr 08 '13 at 13:24
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The main problem is with the new commits on different prefixes since you did your first add. My solution to this problem is to do a "clean-up" operation where you filter all of your changes that are not in other repositories and then do a git subtree add on this new branch.

This is a rather brute-force way of doing it but it's basically the same as saying do a "git subtree add" on a fresh copy of your main repository. That's the only thing that worked for me...

owagh
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