Resolving git conflicts for chained PRs after squash/merge commit

git-chain-conflicts.md

Assuming that there was a:

• PR1 based on branch main
• PR2 based on PR1

And after squash-merging PR1 into the main branch, sometimes we can't just merge PR2 due to a conflicts arising from the commits in PR1 being squashed.

Here's the step-by-step explanation of the Git workflow to resolve this issue:

1. git switch main
2. Reset the main branch to the state it was in right after PR1 was merged:

   git reset --hard [PR1-SHA-COMMIT]
   

3. Create a patch file that captures the changes made in PR2 relative to the state of the main branch:

   git diff main..PR2 > /tmp/diff.patch
   

4. Create a new branch resolve-merge-issues:

   git switch -c resolve-merge-issues
   

5. Apply the changes from PR2 to the resolve-merge-issues branch:

   git apply /tmp/diff.patch
   

6. Create a single commit that combines all the changes from PR2:

git commit -a -m "Merge commit"

6. git switch PR2
7. Merge the single commit created in step 6, which contains the changes from PR2, into the PR2 branch:

   git merge resolve-merge-issues
   

After completing these steps, the actual main branch should now be mergeable into PR2 without conflicts.