I have a git project contains 10 submodules project. I migrated this project to another as a single project. (All submodules are just a folder in the new project now)
Is there anyway to migrate the history data of files in the submodules to new one?
For each submodule, you would need to import their history into the main Git project repository.
You have an example in the 2013 article "Integrating a submodule into the parent repository" from Lucas Jenß.
The idea is to clone the submodule repository beside the main parent one:
•
├── parent/
└── sub/
Remove the submodule declaration in the parent repo:
git submodule deinit -f -- path/to/submodule
rm -rf .git/modules/path/to/submodule
git rm -f path/to/submodule
Rewrite the sub/ repository history in order to move each element to the right path (the path/to/submodule one it was in the parent repository as a submodule)
However, Lucas is using a (now 2022) old obsolete git filter-branch command in order to move each submodule element to the path it needs to have in the parent repository:
CMD="git ls-files -s | sed \"s/${TAB}/${TAB}$TARGET_PATH\//\" | \
GIT_INDEX_FILE=\${GIT_INDEX_FILE}.new \
git update-index --index-info && mv \${GIT_INDEX_FILE}.new \${GIT_INDEX_FILE}"
It was valid (but cumbersome and not fool-proofed against corner case, like empty commits) in 2013.
These days (2022), it is achieved with git filter-repo (after installation, as it is python-based)
cd sub
git filter-repo --to-subdirectory-filter path/to/submodule
# done!
Finally, merge the sub history into the parent one:
$ git remote add sub ../sub/
$ git fetch sub
$ git merge --allow-unrelated-histories --no-commit sub/master
Automatic merge went well; stopped before committing as requested
Repeat that for all 10 submodules.
And you get one single Git project, with each submodule history preserved.