Maybe I wasn't very clear on how the ratchet works. The changes are
gradual yes, but it doesn't leave you an option: if you touch a file you
will it will have to conform to the coding style afterwards. It's not
like the previous gradual process we had before where it would be based
on people actively working towards a style.
That being said, I also completely like the option of just doing one big
change commit.
Regarding actual coding styles: we're a bit limited by what tools exist.
I like Spotless because it can be used to both check and apply a style.
Then you need a formatter that works with Spotless and of those we only
have the Eclipse Formatter, google-java-format, and Prettier. Prettier
is a Javascript tool that I would like to avoid. Eclipse is doable but
you need to fiddle with configuration files. I like google-java-format
because of it's take-it-or-leave-it approach. You either use the style
or you don't but it's very thorough. The downside is that it won't do
tabs-only formatting.
Best,
Aljoscha
On 06.10.20 17:43, Arvid Heise wrote:
After having written that I did a quick search, you can even use git blame
with one big massive change commit [1], which would further help the idea
of "just get over with it".
With that option, I'd even change all whitespaces if the community thinks
that it's a better option (a separate discussion that I'll gladly skip).
[1]
https://www.moxio.com/blog/43/ignoring-bulk-change-commits-with-git-blame
On Tue, Oct 6, 2020 at 5:38 PM Arvid Heise <ar...@ververica.com> wrote:
I'm also +1 for automatically enforceable code style.
I also would just go over it as Chesnay said. While it makes some changes
a bit harder to track (inline git blame), it's easy to skip over in any git
history and if it's only one massive commit, then it's also much easier to
ignore than many gradual changes. Further, if we just do it once, git blame
will quickly become more reliable again.
Btw I completely don't care about the code style as long as it plays well
with IntelliJ (it used to be different, but things change :p).
On Tue, Oct 6, 2020 at 5:23 PM Chesnay Schepler <ches...@apache.org>
wrote:
We shouldn't switch to spaces _now_; cutting this bit from your proposal
will massively simplify things and there's hardly any value in changing
it.
Also I'm getting rather tired of this constant idea of "gradual
application". We've been doing this for 2-3 years now since we
introduced Checkstyle and basically got nowhere. We should just bite the
bullet and get it over with; we could've solved this whole problem
already.
In conclusion, I'm +1 on finally locking down the codestyle and applying
it immediately, I'm -1 on any gradual application scheme because they
_just don't work_.
On 10/6/2020 2:15 PM, Aljoscha Krettek wrote:
Hi All,
I know I know, but please keep reading because I recently learned
about some new developments in the area of coding-style automation.
The tool I would propose we use is Spotless
(https://github.com/diffplug/spotless). This doesn't come with a
formatter but allows using other popular formatters such as
google-java-format. The nice thing about Spotless is that it serves as
a verifier for CI but can also apply the configured style
automatically. That is, for the programmer all she has to do is `mvn
spotless:apply` to fix any style violations.
An interesting feature, which was (somewhat) recently added is
"ratchet"
(
https://github.com/diffplug/spotless/blob/main/plugin-maven/README.md#ratchet).
With this, you can set up Spotless to only apply it's rules to files
that were changed after a configured commit. This would allow a
gradual application of the new coding style instead of one big change.
If we decide to use Spotless, we would of course also have to decide
on a coding style. For this I would propose google-java-format, which
the flink-statefun project uses. The main difference from our current
"style" is that this uses spaces instead of tabs for indentation. By
default it would be 2 spaces but it can be configured to use 4 spaces
which would make code look more or less like our current style. There
are no more configuration knobs, so using tabs is not an option.
Finally, why should we do this? I think most engineers agree that
having a common enforced style is good to have so I only want to
highlight a few thoughts here about things we could improve:
- No more nits about coding style in reviews, this makes it easier
for both the reviewer and developer
- No manual fixing of Checkstyle errors because Spotless can do that
automatically
- Because Flink is such a big project little islands of coding style
have formed between people that commonly work on components. It can be
a nuisance when you work on a different component and then reviewers
don't like your typical coding style. And you first have to get used
to the slight differences in style when reading code.
There are also downsides I see in this:
- We break the history, but both "git blame" and modern IntelliJ can
ignore whitespace when attributing changes. So for files that are
already "well" formatted not much would change.
- In the short-term it will be harder to apply changes both to master
and one of the release-x branches because formatting will be
different. I think this is not too hard though because Spotless can
automatically apply the style.
In summary, we would have some short-term pain with this but I think
it would be good in the long run. What are your thoughts?
Best,
Aljoscha
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