Git: Cherry-pick a commit into a branch and resolve a merge conflict

Here’s the merge conflict message our merge master got when she tried to cherry pick my pull request (PR) to version 4.7 of the published OpenShift docs (lines , below).

openshift-cherrypick-robot commented 4 days ago • 
@theythemself: #29573 failed to apply on top of branch "enterprise-4.7":

Applying: [RHDEVDOCS-2614](https://issues.redhat.com/browse/RHDEVDOCS-2614) Define ClusterLogForwarder compatability Matrix
Using index info to reconstruct a base tree...
M	logging/cluster-logging-external.adoc
Falling back to patching base and 3-way merge...
Auto-merging logging/cluster-logging-external.adoc
CONFLICT (content): Merge conflict in logging/cluster-logging-external.adoc
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 [RHDEVDOCS-2614](https://issues.redhat.com/browse/RHDEVDOCS-2614) Define ClusterLogForwarder compatability Matrix
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

Here, I start by deleting the enterprise-4.7 branch (line ) because it had a previous unmerged commit sitting at the top of the pile. (In the future, I think I’ll avoid this by creating a working branch off of the enterprise-4.7 branch.)

[memyself@memyself openshift-docs]$ git checkout master
Switched to branch 'master'
Your branch is up to date with 'upstream/master'.

[memyself@memyself openshift-docs]$ git branch -D enterprise-4.7
Deleted branch enterprise-4.7 (was 803d05ddd).

Next, I create a new enterprise-4.7 branch that tracks Red Hat’s upstream repo (line). I don’t track my forked copy of the repo, origin, because it has that previous unmerged commit sitting at the top of the pile. (Again, there are other better ways to deal with that problem, I’m just sharing the one I used here.)

[memyself@memyself openshift-docs]$ git checkout --track upstream/enterprise-4.7
Branch 'enterprise-4.7' set up to track remote branch 'enterprise-4.7' from 'upstream'.
Switched to a new branch 'enterprise-4.7'

I fetch the latest changes from upstream and use status to verify that my branch is up to date.

[memyself@memyself openshift-docs]$ git fetch upstream
remote: Enumerating objects: 6, done.
remote: Counting objects: 100% (6/6), done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 6 (delta 4), reused 5 (delta 4), pack-reused 0
Unpacking objects: 100% (6/6), 1.22 KiB | 1.22 MiB/s, done.
From github.com:openshift/openshift-docs
   335951a8d..0f6dbceae  enterprise-4.5 -> upstream/enterprise-4.5

[memyself@memyself openshift-docs]$ git status
On branch enterprise-4.7
Your branch is up to date with 'upstream/enterprise-4.7'.

nothing to commit, working tree clean

I go to the pull request with the failed cherry pick and copy the hash of the commit. I always squash commits so each pull request has only one commit.

I cherry pick that commit into the 4.7 branch. The merge conflict on line 5 is expected.

[memyself@memyself openshift-docs]$ git cherry-pick 3cad05d66d11c2d38a08322222f6c9dcbfc839ab
Auto-merging modules/olm-mirroring-package-manifest-catalog.adoc
Auto-merging modules/cluster-logging-deploy-console.adoc
Auto-merging modules/cluster-logging-deploy-cli.adoc
CONFLICT (content): Merge conflict in modules/cluster-logging-deploy-cli.adoc
error: could not apply 3cad05d66... RHDEVDOCS-2589 OpenShift Logging: Update any installation/upgrade specific information to use our new channels.
hint: after resolving the conflicts, mark the corrected paths
hint: with 'git add <paths>' or 'git rm <paths>'
hint: and commit the result with 'git commit'

I check the status.

[memyself@memyself openshift-docs]$ git status
On branch enterprise-4.7
Your branch is up to date with 'upstream/enterprise-4.7'.

You are currently cherry-picking commit 3cad05d66.
  (all conflicts fixed: run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   logging/cluster-logging-exported-fields.adoc
	modified:   logging/cluster-logging-upgrading.adoc
	modified:   modules/cluster-logging-configuring-image-about.adoc
	modified:   modules/cluster-logging-deploy-cli.adoc
	modified:   modules/cluster-logging-deploy-console.adoc
	modified:   modules/cluster-logging-eventrouter-deploy.adoc
	modified:   modules/cluster-logging-log-store-status-comp.adoc
	modified:   modules/cluster-logging-updating-logging.adoc
	modified:   modules/cluster-logging-visualizer-kibana.adoc
	modified:   modules/olm-mirroring-package-manifest-catalog.adoc

In Atom editor (not shown here), I inspect the file that contains the conflict, modules/cluster-logging-deploy-cli.adoc. In it, I select the set of changes I want to keep. Then, I stage and commit the changes.

Back on the command line, I complete the cherry pick process.

[memyself@memyself openshift-docs]$ git cherry-pick --continue

I -f force push the changes to 4.7 to origin, which is my fork of the repo.

[memyself@memyself openshift-docs]$ git push -f origin enterprise-4.7
Enumerating objects: 27, done.
Counting objects: 100% (27/27), done.
Delta compression using up to 8 threads
Compressing objects: 100% (14/14), done.
Writing objects: 100% (14/14), 1.62 KiB | 1.62 MiB/s, done.
Total 14 (delta 13), reused 0 (delta 0), pack-reused 0
remote: Resolving deltas: 100% (13/13), completed with 13 local objects.
To github.com:rolfedh/openshift-docs.git
 + 803d05ddd...bcc5f087b enterprise-4.7 -> enterprise-4.7 (forced update)

Finally, on GitHub, in rolfedh/openshift-docs, I create the pull request to merge the commit into openshift:enterprise-4.5 from rolfedh:enterprise-4.5.

I’ll need to repeat this process and come up with a more complete set of screenshots.

Here’s a TLDR version of this blog post: Job aid: Git cherry-pick a commit and manually resolve a conflict
I use this short version to copy/paste commands into my terminal.