Here is the flow of gerrit code review.

• Engineer commit change list in local git and push to gerrit for review.

  $git add file

  $git commit -m "message"

  $git push origin HEAD:refs/for/<branch name>

  Engineer should add reviewers one by one to review the CL.

• When code in review, engineer can amend the CL and push that into gerrit again as patch set 2, 3 etc.

  $git add file

  $git commit --amend

  $git push origin HEAD:refs/for/<branch name>

• The reviewer can provide comment in gerrit, and provides score as -1, 0, or 1.

  The +1 stands for agree with the CL and -1 for disagree with it.

  The reviewer can provide comment in gerrit, and provides score as -1, 0, or 1.

• The integrator can provide -2 or +2 for the CL, based on reviewers' comment and other rules.

  The +2 rating moves CL into "Ready for submit" state. The integrator can click "Submit" button to merge the CL. Only integrator has this privilege.

  The -2 rating moves CL into "Cannot be merged" state. Then no one else can merge the CL, even other integrator. Only integrator has this privilege.

• The integrator can merge CL with +2 rating into git repository, or provide -1 to get it back to code review.

• The integrator can provide +1 to "Cannot be merged" to bring it back to code review status. It should be the same integrator who provides -2 to the CL. In another word, if integrator A provides -2 and integrator B provides +1, the CL is still in "Cannot be merged" status, until integrator A provides +1.

• The CL owner or integrator can abandon CL in code review state or "Cannot be merged" state.

  Eventually, one CL is either merged or abandoned in gerrit.