LabelTypes: Return an Optional to make clear that value can be absent

When asking LabelTypes for a LabelType by name or ID, that LabelType
is only returned if the project has a label with name or ID

Most places in Gerrit correctly handled this implicit behavior, but
new code for SubmitRequirements (ChangeField:getMaxMinAnyLabels) did
not which made it fail with a NullPointerException in case a label
that was voted on the change was removed from project.config
since the vote was granted.

In this commit, we fix the NPE by reworking LabelTypes to return
an Optional which also makes it so that this programmer error
can't occur in the future.

Change-Id: I9e0f3a940ce21ef1e46b3dbb1675267ae1d76459
23 files changed
tree: 5d38fd08e28d78b2a16cca37dc41bae87d22548d
  1. .bazelignore
  2. .bazelproject
  3. .bazelrc
  4. .bazelversion
  5. .editorconfig
  6. .git-blame-ignore-revs
  7. .gitignore
  8. .gitmodules
  9. .gitreview
  10. .mailmap
  11. .pydevproject
  12. .settings/
  13. .ts-out/
  14. .zuul.yaml
  15. BUILD
  17. Documentation/
  19. Jenkinsfile
  23. antlr3/
  24. contrib/
  25. e2e-tests/
  26. java/
  27. javatests/
  28. lib/
  29. modules/
  30. package.json
  31. plugins/
  32. polygerrit-ui/
  33. prolog/
  34. prologtests/
  35. proto/
  36. resources/
  37. tools/
  38. twinkie.patch
  39. version.bzl
  40. webapp/
  41. yarn.lock

Gerrit Code Review

Gerrit is a code review and project management tool for Git based projects.

Build Status Maven Central


Gerrit makes reviews easier by showing changes in a side-by-side display, and allowing inline comments to be added by any reviewer.

Gerrit simplifies Git based project maintainership by permitting any authorized user to submit changes to the master Git repository, rather than requiring all approved changes to be merged in by hand by the project maintainer.


For information about how to install and use Gerrit, refer to the documentation.


Our canonical Git repository is located on There is a mirror of the repository on Github.

Reporting bugs

Please report bugs on the issue tracker.


Gerrit is the work of hundreds of contributors. We appreciate your help!

Please read the contribution guidelines.

Note that we do not accept Pull Requests via the Github mirror.

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Gerrit is provided under the Apache License 2.0.


Install Bazel and run the following:

    git clone --recurse-submodules
    cd gerrit && bazel build release

Install binary packages (Deb/Rpm)

The instruction how to configure GerritForge/BinTray repositories is here

On Debian/Ubuntu run:

    apt-get update & apt-get install gerrit=<version>-<release>

NOTE: release is a counter that starts with 1 and indicates the number of packages that have been released with the same version of the software.

On CentOS/RedHat run:

    yum clean all && yum install gerrit-<version>[-<release>]

On Fedora run:

    dnf clean all && dnf install gerrit-<version>[-<release>]

Use pre-built Gerrit images on Docker

Docker images of Gerrit are available on DockerHub

To run a CentOS 8 based Gerrit image:

    docker run -p 8080:8080 gerritcodereview/gerrit[:version]-centos8

To run a Ubuntu 20.04 based Gerrit image:

    docker run -p 8080:8080 gerritcodereview/gerrit[:version]-ubuntu20

NOTE: release is optional. Last released package of the version is installed if the release number is omitted.