Generate mercurial based webrevs from current git based jdk repo?

Erik Helin erik.helin at
Wed Mar 11 16:20:07 UTC 2020

On 3/6/20 3:24 PM, Jaikiran Pai wrote:
> I'm looking for inputs on whether the current state of git repos at [1]
> can be used as a source for contributing to upstream mercurial backed
> jdk repos. More specifically is the following workflow supported (and if
> it is, what are the tools to use):
> - Clone the openjdk/jdk repo
> - Pick any issue or enhancement to contribute to and create a local
> feature/bug-fix branch for it
> - Work on the fix, commit it to that local git branch
> - Use some (variation of webrev) tool which will then generate a
> mercurial based patch comparing the local (git branch) against the
> latest upstream jdk repo's master branch (either git or mercurial).
> Upload this webrev to for reviews.
> So far I've been only using mercurial repos and just creating commits
> locally on top of the "default" branch and then using the webrev tool to
> generate the webrevs. I would like to move to the git based repos if the
> above workflow is supported through some tooling.

Yep, it is :)

If you want to use Git and the read-only jdk mirror on GitHub [0] then 
you need install the Skara CLI tools [1] to get the Git ports of webrev, 
defpath and jcheck (you can ignore the instructions about personal 
access tokens since you will only be using git-webrev, git-jcheck and 

Once you have installed the Skara CLI tools your workflow would look 
like the following to create a webrev and send it out for review:

$ git clone jdk.git
$ cd jdk.git
$ git checkout -b JDK-8142314 # create a local branch for the issue
$ # hack, hack
$ git commit -m '8142314: A bugfix'
$ git webrev
$ # upload webrev to

If you want to learn more about Git then we strongly recommend the 
online version of the "Pro Git" book [3].

You can then send out the resulting webrev for review. Once you have 
gotten reviews and are ready to push your change, then you need to use 
Mercurial and a Mercurial repository to do the final push:

$ hg clone jdk.hg
$ cd jdk.hg
$ hg apply --no-commit <URL-to-patch-in-approved-webrev>
$ hg commit # add "Reviewed-by: " etc.
$ hg push

> Of course, if/when the
> mercurial repos are moved to the git repos, we won't need the part where
> the webrev generates a mercurial patch/webrev from the git repo, so this
> is kind of stop-gap arrangement I am looking for.

Correct, but it is also a nice way to teach yourself Git and get used to 
the Git commands.


> [1]
> -Jaikiran

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