Submodule Changes in PR

TODO: collapasable, copyable, download, etc

I have a pull request on github. Everything looks good, except a git submodule shows up as having changes, but I didn't do anything with that directory. There is a file list with +17 -19 filename, but no diff or details. What is going on? Is it safe to merge my PR?It sounds like the submodule reference in your pull request has changed, which means that the commit pointer for the submodule is pointing to a different commit than it was before. When you see +17 -19 for a submodule, it's an indication of how many commits ahead or behind the submodule pointer is in your branch compared to the target branch, rather than a diff of actual file changes within the submodule.

Here's what might have happened:

1. Submodule Update Without Intent: Sometimes, if you ran certain Git commands without being aware of how they interact with submodules, you might've inadvertently updated the submodule pointer.

2. Different Pointers in Base and Feature Branch: If the branch you're trying to merge into (e.g., main or master) has had its submodule pointer updated after you branched off, and you've made updates in your feature branch as well, it can result in such differences.

To ensure safety and clarity, follow these steps:

1. Check the Submodule Commit Pointers: You can check which commit the submodule is pointing to on both the source and target branches.

   git rev-parse HEAD:path/to/submodule
   

   Replace path/to/submodule with the path to your submodule directory. Running this command on both branches will show the commit SHAs, which you can then compare.

2. See the Actual Changes in Submodule: Navigate to the submodule directory and checkout the relevant commits to see what has actually changed.

   cd path/to/submodule
   git log old_commit_sha..new_commit_sha
   

   This will show you a log of commits between the old and new pointers.

3. Reset the Submodule (If Needed): If you decide you didn't want any changes in the submodule:

   git submodule update --recursive
   

   This command will reset your submodule to the commit that the main project expects it to be at. If this is the right action, after this, you can commit the change and update your pull request.

4. Talk with Your Team: If the submodule update was unintentional or if you're not sure about the changes, talk with your team or the maintainer of the submodule to understand if the update is necessary or correct. It's possible that they made an update that you need to incorporate, or they can clarify the situation.

5. Review Pull Request Before Merging: Always review the entire pull request changes, including submodules, before merging. If there's uncertainty, it might be a good idea to pull the PR locally and test it out, especially if the submodule contains critical code.

Lastly, it's always a good idea to keep submodules up-to-date with their latest stable versions, but such updates should be done deliberately, with understanding, and ideally as separate PRs to keep changes atomic and reviewable.git rev-parse HEAD:path/to/submodule 3a00b4966, but main has d7b8070d9. How can I update it?If the submodule pointer in your branch (3a00b4966) is behind the one in main (d7b8070d9), and you want to update your branch to point to the same commit as main, you can do the following:

1. Ensure Your Branch is Checked Out:

   git checkout your-feature-branch
   

2. Update Your Local main (or whichever branch you're targeting):

   git fetch origin
   git checkout main
   git pull origin main
   

3. Go Back to Your Feature Branch:

   git checkout your-feature-branch
   

4. Update the Submodule: Firstly, go into the submodule directory:

   cd path/to/submodule
   

   Then, checkout the desired commit (in this case, the one from main):

   git checkout d7b8070d9
   

   Go back to your main project directory:

   cd ../..
   

5. Commit the Submodule Update: Now, you'll see the submodule pointer has changed in the main project. You'll need to commit this change:

   git add path/to/submodule
   git commit -m "Update submodule to latest commit from main"
   

6. Push the Changes:

   git push origin your-feature-branch
   

Now your feature branch has the submodule updated to the same commit as in main. When you look at your pull request, the submodule difference should no longer be there.

Remember, always make sure you understand what changes are in the submodule's new commit, and test to ensure nothing breaks in your main project due to the submodule update.Nothing changed in my submodule, I never touched itIf you never touched the submodule and you're seeing this discrepancy, it's possible that the base branch (e.g., main) has advanced its submodule pointer and your feature branch just needs to reflect that update.

Here's a streamlined approach to get your feature branch's submodule pointer to match that of main:

1. Ensure Your Branch is Checked Out:

   git checkout your-feature-branch
   

2. Update Your Local main:

   git fetch origin
   git merge origin/main
   

3. Update the Submodule to Match main:

   git submodule update --recursive
   

4. Commit the Updated Submodule Pointer: If the submodule reference has changed, you will need to commit this change.

   git add path/to/submodule
   git commit -m "Sync submodule with main branch"
   

5. Push the Changes:

   git push origin your-feature-branch
   

After these steps, the submodule pointer in your feature branch should match that of the main branch, resolving the discrepancy in the pull request. Remember to double-check the pull request on GitHub to ensure the submodule no longer shows up as changed.

Submodule Changes in PR created at Tue Jan 20 1970 15:46:03 GMT+0000 (Coordinated Universal Time)