Fix Gerrit login with Google OAuth 2: com.google.gerrit.server.account.AccountException: Cannot assign external ID to account 1000007; external ID already in use.

We have figured out to fix this issue by performing actions in the All-Users repos in Server.By using this workaround users can access the Gerrit application back.

git clone /gerrit/gerrit/git/All-Users.git/

cd All-Users/

git fetch origin refs/meta/external-ids:refs/meta/external-ids

git checkout refs/meta/external-ids

git log

git show fa89bc7791e1dfd3fb6c595b3cf9969a0b60beaa # the sha should be the one when the account was created

rm files found in the git show log

git add *

git commit -m "Fix the external id error"

git push origin HEAD:refs/meta/external-ids (sudo maybe needed)

You may also need to modify gerrit site: mv db/account_patch_reviews.h2.db db/account_patch_reviews.h2.db.backup. rm -rf cache/*

Restart gerrit