How to avoid "Updates were rejected because the remote contains work" during release with maven release-plugin and git?

Question

We recently migrated from SVN to git. Beside other (unexpected) issues doing releases on git, I am wondering how to deal with the following issue:

When I start a release-run on Jenkins and some developer (accidentally) pushes during the first phase of the release, the release build fails with the following error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-release-plugin:2.5.3:prepare (default-cli) on project xyz: Unable to commit files
[ERROR] Provider message:
[ERROR] The git-push command failed.
[ERROR] Command output:
[ERROR] To ssh://[some-ip]/home/git/xyz
[ERROR] ! [rejected]        release/xyz-6.10 -> release/xyz-6.10 (fetch first)
[ERROR] error: failed to push some refs to 'ssh://[some-ip]/home/git/xyz'
[ERROR] hint: Updates were rejected because the remote contains work that you do
[ERROR] hint: not have locally. This is usually caused by another repository pushing
[ERROR] hint: to the same ref. You may want to first integrate the remote changes
[ERROR] hint: (e.g., 'git pull ...') before pushing again.
[ERROR] hint: See the 'Note about fast-forwards' in 'git push --help' for details.
[ERROR] -> [Help 1]

The maven command used by Jenkins to initiate the release build is (we build on Windows, so we unfortunately have to activate -DautoVersionSubmodules due to otherwise too long command line on the git add including all the modified pom.xml):

mvn -B -DdevelopmentVersion=xyz-6.10.0-rc3-SNAPSHOT -DreleaseVersion=xyz-6.10.0-rc2 -Dtag=xyz-6.10.0-rc2 -Dresume=false -e -Dgoals=deploy -DautoVersionSubmodules=true -DcommitByProject=true -P[some-profiles] -T1C release:prepare release:perform -Darguments=-T1C

Is there a simple way to block other users from pushing (but allow Jenkins to push!)? Or any other stable work around - or best practice?

Versions used:

• Maven 3.3.9
• Maven Release-Plugin 2.5.3
• Git 2.8.1
• Jenkins 1.629
• Jenkins Maven Release Plug-in Plug-in 0.14.0
• Windows 10

Thank you in advance for your help.

Answer 1

I hope you agree that is was correct that the release failed. And in this case it is not a big issue to fix: update the project and do another release. The easiest way to fix this is: communication :) Simply informing coworkers that you plan to do this release. Another solution I have heard of is: create a branch first and release from this branch. Nobody will change the content of the branch, so this should be a safe solution, but it requires extra work. It's up to you to decide if it's worth it. Most of the time it is not.