[No QA] Fix NewDot deploys

[roryabraham]

Details

Interestingly, there were two separate issues, one that caused the production deploy to fail, and another that caused the staging deploy to fail.

Production

First, the production deploy failed with this error:

error: pathspec 'staging' did not match any file(s) known to git

This happened because this comment wasn't entirely accurate. While we're guaranteed to have a branch, we're not guaranteed to have all the branches we need. To fix that is simple – just run a git fetch from within the action. That way we'll have all the branches from the remote.

Staging

Second, the staging deploy failed because this command: git merge -Xtheirs main failed with this error:

CONFLICT (modify/delete): .github/actions/isPullRequestMergeable/isPullRequestMergeable.js deleted in main and modified in HEAD.  Version HEAD of .github/actions/isPullRequestMergeable/isPullRequestMergeable.js left in tree.
Auto-merging .github/actions/javascript/isPullRequestMergeable/index.js
Auto-merging .github/workflows/cherryPick.yml
Auto-merging .github/workflows/createNewVersion.yml
Auto-merging .github/workflows/deploy.yml
CONFLICT (modify/delete): .github/workflows/updateProtectedBranch.yml deleted in main and modified in HEAD.  Version HEAD of .github/workflows/updateProtectedBranch.yml left in tree.
Auto-merging android/app/build.gradle
Auto-merging ios/NewExpensify/Info.plist
Auto-merging ios/NewExpensifyTests/Info.plist
Auto-merging package-lock.json
Auto-merging package.json
Auto-merging src/components/OptionsSelector.js
Auto-merging src/libs/actions/Policy.js
Auto-merging src/libs/actions/Report.js
Auto-merging src/pages/home/report/ReportActionCompose.js
Auto-merging tests/unit/isPullRequestMergeableTest.js
Automatic merge failed; fix conflicts and then commit the result.

I believe it's only by luck/coincidence that this hasn't happened before. Normally we do the following, with the intention of completely overwriting the staging branch with main:

git checkout staging
BRANCH_NAME=update-staging-from-main
git checkout -b "$BRANCH_NAME"
git merge -Xtheirs main
git push --set-upstream origin "$BRANCH_NAME"

The key piece here is the -Xtheirs flag, which basically says "if there's a conflict, use the version of the code from main". However, that doesn't work in the specific scenario where a file was modified on staging and deleted on main. Because we want to prioritize the changes from main, we'll automatically resolve the conflicts using the change from main, using the following command:

git merge -Xtheirs main || git diff --name-only --diff-filter=U | xargs git rm && git merge --continue

And what this says is basically:

"Merge main into staging, and if there's a conflict, use the version of the code from main. If that doesn't work, delete any files that failed to merge automatically and continue."

This is safe, because the inverse scenario (a file is edited on main but deleted on staging) is not possible because all changes propagate from main -> staging -> production.

Fixed Issues

$ n/a – broken deploys.

Local Test

Go to the App repo locally and run these commands:

git fetch
git checkout main
git checkout -b fake-main
git checkout main
git checkout -b fake-staging
echo "Update README on staging" >> README.md
git add README.md
git commit -m "Update README on staging"
git checkout fake-main
rm README.md
git add README.md
git commit -m "Delete README on main"
git checkout fake-staging
git merge -Xtheirs fake-main || {
  git diff --name-only --diff-filter=U | xargs git rm;  
  git merge --continue;
}

It will most likely open a pager for the commit message (but that won't happen in the GH Actions runner by default), but otherwise the commit should succeed.

Live Test

1. Merge this PR
2. Ship the checklist again.
3. The deploy should work.

[chiragsalian]

can you explain the functionality of the double and single pipe here?

[roryabraham]

So this has been replaced by the following:

git merge -Xtheirs main || {
  git diff --name-only --diff-filter=U | xargs git rm;
  git merge --continue;
}

Breaking that down:

1. First we try to execute git merge -Xtheirs main
2. If that fails, the || will ensure that the next statement will run. If it succeeds, the next statement will not run.
3. The next statement is a command group – everything inside the {} is treated as a single command in the same shell.
   1. git diff --name-only --diff-filter=U will list the names of unmerged files in the ongoing git merge
   2. We pipe those unmerged files into git rm using xargs. Basically the output of the git diff command becomes the argument for git rm. In effect, we're running git rm on all the unmerged files.
   3. Lastly, we'll continue with the git merge.

[luacmartins]

Code LGTM, tests are failing though

[roryabraham]

Okay, going to merge so we can test and hopefully deploy NewDot.

[OSBotify]

✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release.

[OSBotify]

🚀 Deployed to staging by @roryabraham in version: 1.1.81-0 🚀

platform	result
🤖 android 🤖	failure ❌
🖥 desktop 🖥	success ✅
🍎 iOS 🍎	success ✅
🕸 web 🕸	failure ❌

[OSBotify]

🚀 Deployed to production by @roryabraham in version: 1.1.82-5 🚀

platform	result
🤖 android 🤖	success ✅
🖥 desktop 🖥	success ✅
🍎 iOS 🍎	failure ❌
🕸 web 🕸	success ✅