How to import existing Git repository into another

Question

I have a Git repository in a folder called XXX  and I have second Git repository called YYY   I want to import the XXX repository into the YYY repository as a subdirectory named ZZZ and add all XXX s change history to YYY   Folder structure before    -- XXX       --  git       --  project files   -- YYY      --  git      --  project files    Folder structure after   YYY  --  git   lt -- This now contains the change history from XXX  --  ZZZ   lt -- This was originally XXX        --  project files   --   project files    Can this be done  or must I resort to using sub-modules

User · Answer

I don t know of an easy way to do that   You COULD do this    Use git filter-branch to add a ZZZ super-directory on the XXX repository Push the new branch to the YYY repository Merge the pushed branch with YYY s trunk    I can edit with details if that sounds appealing

User · Answer

The simple way to do that is to use git format-patch   Assume we have 2 git repositories foo and bar   foo contains    foo txt  git   bar contains    bar txt  git   and we want to end-up with foo containing the bar history and these files     foo txt  git foobar bar txt   So to do that    1  create a temporary directory eg PATH YOU WANT patch-bar  2  go in bar directory  3  git format-patch --root HEAD --no-stat -o PATH YOU WANT patch-bar --src-prefix a foobar  --dst-prefix b foobar   4  go in foo directory  5  git am PATH YOU WANT patch-bar     And if we want to rewrite all message commits from bar we can do  eg on Linux   git filter-branch --msg-filter  sed  1s     bar       COMMIT SHA1 OF THE PARENT OF THE FIRST BAR COMMIT  HEAD   This will add   bar    at the beginning of each commit message

User · Answer

I can suggest another solution  alternative to git-submodules  for your problem - gil  git links  tool  It allows to describe and manage complex git repositories dependencies    Also it provides a solution to the git recursive submodules dependency problem   Consider you have the following project dependencies  sample git repository dependency graph  Then you can define  gitlinks file with repositories relation description     Projects CppBenchmark CppBenchmark https   github com chronoxor CppBenchmark git master CppCommon CppCommon https   github com chronoxor CppCommon git master CppLogging CppLogging https   github com chronoxor CppLogging git master    Modules Catch2 modules Catch2 https   github com catchorg Catch2 git master cpp-optparse modules cpp-optparse https   github com weisslj cpp-optparse git master fmt modules fmt https   github com fmtlib fmt git master HdrHistogram modules HdrHistogram https   github com HdrHistogram HdrHistogram c git master zlib modules zlib https   github com madler zlib git master    Scripts build scripts build https   github com chronoxor CppBuildScripts git master cmake scripts cmake https   github com chronoxor CppCMakeScripts git master   Each line describe git link in the following format    Unique name of the repository Relative path of the repository  started from the path of  gitlinks file  Git repository which will be used in git clone command Repository branch to checkout Empty line or line started with   are not parsed  treated as comment     Finally you have to update your root sample repository     Clone and link all git links dependencies from  gitlinks file gil clone gil link    The same result with a single command gil update   As the result you ll clone all required projects and link them to each other in a proper way   If you want to commit all changes in some repository with all changes in child linked repositories you can do it with a single command   gil commit -a -m  Some big update    Pull  push commands works in a similar way   gil pull gil push   Gil  git links  tool supports the following commands   usage  gil command arguments Supported commands      help - show this help     context - command will show the current git link context of the current directory     clone - clone all repositories that are missed in the current context     link - link all repositories that are missed in the current context     update - clone and link in a single operation     pull - pull all repositories in the current directory     push - push all repositories in the current directory     commit - commit all repositories in the current directory   More about git recursive submodules dependency problem

User · Answer

If you want to retain the exact commit history of the second repository and therefore also retain the ability to easily merge upstream changes in the future then here is the method you want  It results in unmodified history of the subtree being imported into your repo plus one merge commit to move the merged repository to the subdirectory   git remote add XXX remote  lt path-or-url-to-XXX-repo gt  git fetch XXX remote git merge -s ours --no-commit --allow-unrelated-histories XXX remote master git read-tree --prefix ZZZ  -u XXX remote master git commit -m  Imported XXX as a subtree     You can track upstream changes like so   git pull -s subtree XXX remote master   Git figures out on its own where the roots are before doing the merge  so you don t need to specify the prefix on subsequent merges   The downside is that in the merged history the files are unprefixed  not in a subdirectory   As a result git log ZZZ a will show you all the changes  if any  except those in the merged history  You can do   git log --follow -- a   but that won t show the changes other then in the merged history   In other words  if you don t change ZZZ s files in repository XXX  then you need to specify --follow and an unprefixed path  If you change them in both repositories  then you have 2 commands  none of which shows all the changes   Git versions before 2 9  You don   t need to pass the --allow-unrelated-histories option to git merge   The method in the other answer that uses read-tree and skips the merge -s ours step is effectively no different than copying the files with cp and committing the result   Original source was from github s  Subtree Merge  help article  And another useful link

User · Answer

I think you can do this using  git mv  and  git pull    I m a fair git noob - so be careful with your main repository - but I just tried this in a temp dir and it seems to work   First - rename the structure of XXX to match how you want it to look when it s within YYY   cd XXX mkdir tmp git mv ZZZ tmp ZZZ git mv tmp ZZZ   Now XXX looks like this   XXX   - ZZZ       - ZZZ   Now use  git pull  to fetch the changes across   cd    YYY git pull    XXX   Now YYY looks like this   YYY   - ZZZ       - ZZZ   -  other folders that already were in YYY

User · Answer

git-subtree is a script designed for exactly this use case of merging multiple repositories into one while preserving history  and or splitting history of subtrees  though that seems to be irrelevant to this question   It is distributed as part of the git tree since release 1 7 11   To merge a repository  lt repo gt  at revision  lt rev gt  as subdirectory  lt prefix gt   use git subtree add as follows   git subtree add -P  lt prefix gt   lt repo gt   lt rev gt    git-subtree implements the subtree merge strategy in a more user friendly manner   For your case  inside repository YYY  you would run   git subtree add -P ZZZ  path to XXX git master   The downside is that in the merged history the files are unprefixed  not in a subdirectory   As a result git log ZZZ a will show you all the changes  if any  except those in the merged history  You can do   git log --follow -- a   but that won t show the changes other then in the merged history   In other words  if you don t change ZZZ s files in repository XXX  then you need to specify --follow and an unprefixed path  If you change them in both repositories  then you have 2 commands  none of which shows all the changes   More on it here

User · Answer

See Basic example in this article and consider such mapping on repositories    A  lt -  YYY   B  lt -  XXX   After all activity described in this chapter  after merging   remove branch B-master     git branch -d B-master   Then  push changes   It works for me

User · Answer

I wanted to import only some files from the other repository  XXX  in my case  The subtree was too complicated for me and the other solutions didn t work  This is what I did   ALL COMMITS   git log --reverse --pretty format  H -- ZZZ   tr   n         This gives you a space-separated list of all the commits that affect the files I wanted to import  ZZZ  in reverse order  you might have to add --follow to capture renames as well   I then went into the target repository  YYY   added the other repository  XXX  as remote  did a fetch from it and finally   git cherry-pick  ALL COMMITS   which adds all the commits to your branch  you ll thus have all the files with their history and can do whatever you want with them as if they ve always been in this repository

User · Answer

I was in a situation where I was looking for -s theirs but of course  this strategy doesn t exist   My history was that I had forked a project on GitHub  and now for some reason  my local master could not be merged with upstream master although I had made no local changes to this branch   Really don t know what happened there -- I guess upstream had done some dirty pushes behind the scenes  maybe    What I ended up doing was    as per https   help github com articles syncing-a-fork  git fetch upstream git checkout master git merge upstream master        Lots of conflicts  ended up just abandonging this approach git reset --hard     Ditch failed merge git checkout upstream master   Now in detached state git branch -d master     git checkout -b master     create new master from upstream master   So now my master is again in sync with upstream master  and you could repeat the above for any other branch you also want to sync similarly

User · Answer

Adding another answer as I think this is a bit simpler  A pull of repo dest is done into repo to import and then a push --set-upstream url repo dest master is done   This method has worked for me importing several smaller repos into a bigger one   How to import  repo1 to import to repo dest    checkout your repo1 to import if you don t have it already  git clone url repo1 to import repo1 to import cd repo1 to import    now  pull all of repo dest git pull url repo dest ls  git status   shows Your branch is ahead of  origin master  by xx commits    now push to repo dest git push --set-upstream url repo dest master    repeat for other repositories you want to import   Rename or move files and dirs into desired position in original repo before you do the import  e g    cd repo1 to import mkdir topDir git add topDir git mv this that and the other topDir  git commit -m move things into topDir in preparation for exporting into new repo    now do the pull and push to import   The method described at the following link inspired this answer  I liked it as it seemed more simple  BUT Beware  There be dragons  https   help github com articles importing-an-external-git-repository git push --mirror url repo dest pushes your local repo history and state to remote  url repo dest   BUT it deletes the old history and state of the remote  Fun ensues   -E

User · Answer

Let me use names a  in place of XXX and ZZZ  and b  in place of YYY   since that makes the description a bit easier to read   Say you want to merge repository a into b  I m assuming they re located alongside one another    cd a git filter-repo --to-subdirectory-filter a cd    cd b git remote add a    a git fetch a git merge --allow-unrelated-histories a master git remote remove a   For this you need git-filter-repo installed  filter-branch is discouraged    An example of merging 2 big repositories  putting one of them into a subdirectory  https   gist github com x-yuri 9890ab1079cf4357d6f269d073fd9731  More on it here

User · Answer

This function will clone remote repo into local repo dir  after merging all commits will be saved  git log will be show the original commits and proper paths   function git-add-repo       repo   1      dir    echo   2    sed  s              path    pwd        tmp    mktemp -d       remote    echo   tmp    sed  s     g   sed  s      g         git clone   repo    tmp      cd   tmp       git filter-branch --index-filter           git ls-files -s           sed  s  t  amp    dir                GIT INDEX FILE   GIT INDEX FILE new  git update-index --index-info  amp  amp          mv   GIT INDEX FILE new    GIT INDEX FILE        HEAD      cd   path      git remote add -f   remote   file    tmp  git      git pull   remote master      git merge --allow-unrelated-histories -m  Merge repo  repo into master  --edit   remote master      git remote remove   remote      rm -rf   tmp      How to use   cd current package git-add-repo https   github com example example dir to save   If make a little changes you can even move files dirs of merged repo into different paths  for example   repo  https   github com example example  path    pwd    tmp    mktemp -d   remote    echo   tmp    sed  s     g    sed  s      g     git clone   repo    tmp  cd   tmp   GIT ADD STORED     function git-mv-store       from    echo   1    sed  s                to    echo   2    sed  s                 GIT ADD STORED   s  t   from    t   to           NOTICE  This paths used for example  Use yours instead  git-mv-store  public index php   public admin php  git-mv-store  public data   public x  data  git-mv-store  public  htaccess    htaccess  git-mv-store  core config   config config  git-mv-store  core defines php   defines defines php  git-mv-store  README md   doc README md  git-mv-store   gitignore   unneeded  gitignore   git filter-branch --index-filter       git ls-files -s       sed     GIT ADD STORED          GIT INDEX FILE   GIT INDEX FILE new  git update-index --index-info  amp  amp      mv   GIT INDEX FILE new    GIT INDEX FILE    HEAD  GIT ADD STORED     cd   path  git remote add -f   remote   file    tmp  git  git pull   remote master  git merge --allow-unrelated-histories -m  Merge repo  repo into master  --edit   remote master  git remote remove   remote  rm -rf   tmp    Notices Paths replaces via sed  so make sure it moved in proper paths after merging  The --allow-unrelated-histories parameter only exists since git    2 9

User · Answer

There is a well-known instance of this in the Git repository itself  which is collectively known in the Git community as  quot the coolest merge ever quot   after the subject line Linus Torvalds used in the e-mail to the Git mailinglist which describes this merge   In this case  the gitk Git GUI which now is part of Git proper  actually used to be a separate project  Linus managed to merge that repository into the Git repository in a way that  it appears in the Git repository as if it had always been developed as part of Git  all the history is kept intact and it can still be developed independently in its old repository  with changes simply being git pulled   The e-mail contains the steps needed to reproduce  but it is not for the faint of heart  first  Linus wrote Git  so he probably knows a bit more about it than you or me  and second  this was almost 5 years ago and Git has improved considerably since then  so maybe it is now much easier  In particular  I guess nowadays one would use a gitk submodule  in that specific case

User · Answer

Based on this article  using subtree is what worked for me and only applicable history was transferred   Posting here in case anyone needs the steps  make sure to replace the placeholders with values applicable to you    in your source repository split subfolder into a new branch  git subtree split --prefix  lt source-path-to-merge gt  -b subtree-split-result  in your destination repo merge in the split result branch  git remote add merge-source-repo  lt path-to-your-source-repository gt  git fetch merge-source-repo git merge -s ours --no-commit merge-source-repo subtree-split-result git read-tree --prefix  lt destination-path-to-merge-into gt  -u merge-source-repo subtree-split-result   verify your changes and commit  git status git commit   Don t forget to   Clean up by deleting the subtree-split-result branch  git branch -D subtree-split-result  Remove the remote you added to fetch the data from source repo  git remote rm merge-source-repo

User · Answer

Probably the simplest way would be to pull the XXX stuff into a branch in YYY and then merge it into master   In YYY   git remote add other  path to XXX git fetch other git checkout -b ZZZ other master mkdir ZZZ git mv stuff ZZZ stuff                        repeat as necessary for each file dir git commit -m  Moved stuff to ZZZ  git checkout master                 git merge ZZZ --allow-unrelated-histories     should add ZZZ  to master git commit git remote rm other git branch -d ZZZ                             to get rid of the extra branch before pushing git push                                      if you have a remote  that is   I actually just tried this with a couple of my repos and it works  Unlike J  rg s answer it won t let you continue to use the other repo  but I don t think you specified that anyway   Note  Since this was originally written in 2009  git has added the subtree merge mentioned in the answer below  I would probably use that method today  although of course this method does still work

[git] How to import existing Git repository into another?

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