You will create and merge the following Pull Requests.
Fetch the desired protobuf version and copy it in a folder
Example: to upgrade to 3.6.1, download and unpack protobuf-all-3.6.1.zip.
Build the Java proto library from source and, in case you cloned an upstream version of protobuf, remove the .git folders:
cd third_party/protobuf/new_proto bazel build :protobuf_java :protobuf_java_util cp bazel-bin/libprotobuf_java.jar . cp bazel-bin/libprotobuf_java_util.jar . bazel clean --expunge rm -rf .git .gitignore .gitmodules
Reason: Bazel uses upstream protobuf from source, except for Java, as Bazel‘s bootstrapping scripts currently don’t build protobuf Java when bootstrapping Bazel but use pre-built jars instead.
BUILD file to not build java from source, but to use the jars instead:
In the BUILD file delete the rules listed under
third_party/protobuf/<old_proto>/BUILD file copy the rules under the “Modifications made by bazel” section to the new BUILD file. The java rules in there should have the same names as the ones you just deleted under “Java support”. You might need to update the names of the jars in the rules sources to the ones you just build.
third_party/protobuf/<old_proto>/com_google_protobuf_java.BUILD to the new directory.
third_party/protobuf/<old_proto>/third_party/googletest/BUILD.bazel: copy the
licenses declaration and the
srcs filegroup to the corresponding file under
third_party/protobuf/<new_proto>/BUILD, in the
srcs filegroup rule, update the version number referring to the newly added
third_party/protobuf/<new_proto> directory according to the protobuf version number.
Add a new variable
_NEW_PROTOBUF_VERSION, set to value of the version.
srcs filegroup rule, add:
srcs = [ "//third_party/protobuf/" + PROTOBUF_VERSION + ":srcs", + "//third_party/protobuf/" + _NEW_PROTOBUF_VERSION + ":srcs", ],
Create a PR of these changes and merge it directly to https://bazel.googlesource.com/bazel/+/master (without the usual process of importing it to the Google-internal version control).
In the root
WORKSPACE file update relative paths of protobuf to point to the new version.
Update version number in
Update the current version in this file.
Create a PR of these changes and get it imported. Some files won't be imported (those that are only hosted on GitHub); this is expected.
Wait for the imported PR to be pushed back to GitHub. Rebase the PR from the previous step, and merge it to https://bazel.googlesource.com/bazel/+/master .
Create a PR of these changes and merge it directly to https://bazel.googlesource.com/bazel/+/master .
Update this file if you found these instructions to be wrong or incomplete.
The current version of protobuf is 3.6.1.