[llvm-dev] [RFC] Semi-Automatic clang-format of files with low frequency

[Chris Tetreault via llvm-dev]

I’m in favor of this because, like you said, unless we do something like this, we’ll never get there. Frankly, I think the inactive period should be much shorter. I would even go so far as to say something like 1 month of inactivity. This codebase is under heavy development, so any code under active development will likely be touched in a 1 month period. 6-12 months will only catch the truly stable code, but any code that only gets minimal changes will never reach 100% coverage.

I would also like to see a threshold (maybe on a per-file or per-subfolder level of granularity) where once the coverage gets over the threshold, we just “rip the band-aid off” and clang-format everything. Suppose we set the threshold at 90%, and Foo.cpp is over 90% formatted, we just format the entire file and be done with it.

I’m sympathetic to the argument that these sorts of change make managing downstreams more difficult, I maintain one myself.  However, I would argue that finishing the formatting as fast as possible will reduce downstream pain because after the codebase is completely formatted, it’ll just be done and there will be no more formatting churn. As it stands, we constantly have to deal with formatting changes because there’s always new ones.

Thanks,
   Christopher Tetreault

From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of MyDeveloper Day via llvm-dev
Sent: Sunday, June 28, 2020 8:31 AM
To: llvm-dev <llvm-dev at lists.llvm.org>
Subject: [EXT] [llvm-dev] [RFC] Semi-Automatic clang-format of files with low frequency


(Copying from Discourse)

All

A couple of months ago I added the following page documentation Clang-Formatted-Status<http://clang.llvm.org/docs/ClangFormattedStatus.html> to track the status of “How Much” clang-formatted the

LLVM/Clang project is.

I’m a contributor to clang-format and would like to see LLVM 100% clang formatted so we can use LLVM as a massive test-suite for clang-format when we make changes.

In the last couple of months since we added this page the % has gone up by ~4% and this is likely in most part of either: a mention in LLVM-Weekly, the premerge checks or perhaps some recent clang-format efforts by individuals. This is fantastic and every directory that gets to 100% increase the directories that I can run against to check against.

However, it recently twigged to me that files that don’t change very often are never going to be 100% clang-formatted simply by virtue of clang-formatting all new changes.

So I 100% understand this kind of topic comes up from time to time and I understand that we don’t want to automatically clang-format the entire tree as this can disrupt peoples downstream forks, especially where they actively have code inflight.

But I wonder if we could have a general rule that said a [NFC] clang-format change could be made on ANY file that had NOT been changed in a 6/12 months period? I believe this process could be automated at least in a semi-automatic way. Once complete the pre-merge checks should maintain the current status.

This would drive the goal of completely clang-formatted source tree, without the disruption to current active areas.

Any thoughts?

MyDeveloperDay
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20200630/4d79d399/attachment-0001.html>