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So, one could theoretically "embed" an older commit into their repository as a pointer (submodule folder)? And because Git knows what that commit ID means it wi

• AceJohnny2 3y ago
  Unfortunately no, because of how it's a hack, and so extra logic had to be tacked on to support it (logic which the `git submodule` command implements). I tried it out, and the local commit object just appears as an empty folder. To try for yourself, do this: git init recursive-submodule && cd recursive submodule echo "foo" > file1 && git add file1 && git commit -m "Add file1" # this will have created an initial commit with hash 2d49d729. Then: git update-index --add --cacheinfo 160000 2d49d729fe39d1def8ce537d7efeeabbf3efb4f2 submodule && git commit -m "Add submodule" The `update-index` command is the plumbing command for adding an arbitrary object, which I used to add the previous commit object. Since we only updated the index and not the workspace, git will note that the submodule is missing. You can then run `git restore .` to set the workspace to the state the history says (ie with the missing submodule)... but that just creates an empty directory. Vanilla git won't try much further. To actually populate the submodule requires running `git submodule update --init`, and that requires a `.gitmodules` file, even for a local commit object. (To learn more about plumbing commands like update-index, look at the Git Book chapter on Internal Git Objects: https://git-scm.com/book/en/v2/Git-Internals-Git-Objects https://git-scm.com/book/en/v2/Git-Internals-Git-Objects )