Workflows

Git merge

To better understand the difference in between git and git-subrepo we start with describing a merge in git.

    D - E topic
  /      
A - B - C master

$ git checkout master
$ git merge topic

    D - E topic
  /       \
A - B - C - F master

The next time you merge you can rely on the previous parents created.

    D - E - G - H topic
  /       \
A - B - C - F - I master

$ git checkout master
$ git merge topic

    D - E - G - H topic
  /       \       \
A - B - C - F - I - J master

In the example above it will use E as the common ancestor between H and I.

git-subrepo pull

As described in Advanced git-subrepo depends on finding ancestry through content tree hashes. By using this the actual parent connections are not stored explicitly.

#10,a - #20,b - #30,c subrepo
#10,a - #20,b - #30,c subrepo/fetch
#41,a - #51,d - #61,e project/subrepo/branch
#40,A - #50,D - #60,E project

in the case above we find that #10 and #41 have equal tree hash and then it's used as common ancestor. We apply the changes on our project/subrepo/branch onto subrepo/fetch.

#10,a - #20,b - #30,c subrepo
#10,a - #20,b - #30,c - #52,d' - #62,e' subrepo/fetch
#41,a - #51,d - #61,e project/subrepo/branch
#40,A - #50,D - #60,E project

Then apply that onto our project branch again

#10,a - #20,b - #30,c subrepo
#10,a - #20,b - #30,c - #52,d' - #62,e' subrepo/fetch
#41,a - #51,d - #61,e project/subrepo/branch
#40,A - #50,D - #60,E - #63,E' project

As you see, the actual subrepo is still left intact. To "simplify" the next example we rename E' => F, in our project it's a new commit and we don't want to add extra ' in the example. If we decide to move on without pushing our changes, the next pull will look like this

#10,a - #20,b - #30,c - #70,h subrepo
#10,a - #20,b - #30,c - #70,h  subrepo/fetch
#41,a - #51,d - #61,e - #64,f - #81,g project/subrepo/branch
#40,A - #50,D - #60,E - #63,F - #80,G project

As you see here the common ancestor is still a based (#10, #41), so when we rebase everything

Pull only

If you only intend to

Describe the different workflows

• Pull only
• Pull-push
• Local changes