git read-tree to project root

Question

I have my main_repo with folder structure like this

application_root

• app
• • code
• • • foo
• • • • file1
• • • • file2
• • • bar
• skin
• lib
• file1
• file2

It's the main application. And I have another repo with an extension for my main application. The problem is that extension directory layout overlap directories from the root of main project such as

extension_root

• app
• • code
• • • baz
• • • • file1
• • • • file2
• skin
• • file1
• • file2
• file3
• file4

So I can't use submodule tool. I need to merge this two repositories for farther development. I need the ability to merge from extension_repo to main_repo and back as well so if I made changes to my extension which was merged to main_repo I can merge only this changes (without application itself) to extension_repo. I don't know if it even possible. It seems that read-tree merging do what I want but I can't use it in such way

git read-tree --prefix=/ -u extension_remote_branch

because I get this error

error: Entry '.gitignore' overlaps with '.gitignore'.  Cannot bind.

I guess I'll get this error for all directories I have overlaped. I don't actually have overlaped files except of .gitignore.

Answer 1

So far I haven't found a way to do this in a single command via git; so instead I use a fairly straightforward workaround. The basic approach is to read-tree into a second, empty directory. Then move the second directory overtop the first.

The basic flow is:

mkdir upstream-tree
git read-tree --prefix=upstream-tree/ -u myremote/branch
git commit -m "Pulled in remote tree"
cp -rf upstream-tree/* local-tree/
git rm -r upstream-tree
git add local-tree
git commit -m "Merged upstream-tree into local-tree"