[llvm-dev] Codifying our Brace rules-

[Chris Tetreault via llvm-dev]

While I personally would be in favor of the rule becoming "always use braces", I think it's hard to justify the amount of work it would take to realize that goal throughout the codebase. That said, I think it might be worth changing the rule from "Don’t Use Braces on Simple ..." to "Prefer Not to Use Braces on Simple ... " or "Braces May Optionally be Omitted on Simple ...". The old version mandates omitting braces based upon a judgement call. The new versions allow omitting braces based on a judgement call.

Complicated rules that mandate specific things based upon a judgement call are very hard to enforce, and can be infuriating when a developer with more clout than you is blocking your work because their interpretation of the rules differs from your own. I'm not saying this has happened in my work on LLVM, but it has happened to me in my career.

Thanks,
   Christopher Tetreault


-----Original Message-----
From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Chris Lattner via llvm-dev
Sent: Monday, June 22, 2020 1:45 PM
To: Steve Scalpone <sscalpone at nvidia.com>
Cc: llvm-dev at lists.llvm.org; Matt Arsenault <arsenm2 at gmail.com>
Subject: [EXT] Re: [llvm-dev] Codifying our Brace rules-

For those who don’t like it, is the currently documented policy broken enough to be important to changing?

I assume you wouldn’t recommend a massive rewrite of the codebase, so we’re going to be with this for quite some time.

-Chris

> On Jun 22, 2020, at 1:36 PM, Steve Scalpone via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>
> Did this conversation reach a conclusion?
>
> My ad hoc tally says that a slight majority of the responders preferred to fully brace statements and no one wanted to totally eliminate braces.
>
> The technical arguments for fully braced statements were 1) it's considered a slightly safer coding style and 2) commit diffs with fully braced statements may be slightly more to the point.
>
> I didn't register any technical arguments for less-than-fully-braced statement -- the preference seemed to be aesthetic.  I may have missed a technical argument.
>
> Certainly an "always use braces" rule would be simpler than what's documented now in the LLVM Coding Standards [1].
>
> Another option would be to make braces a developer's choice, and ask that those omitting braces please follow the rules documented in [1].
>
> [1]
> https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-
> single-statement-bodies-of-if-else-loop-statements
>
> On 6/18/20, 3:56 AM, "llvm-dev on behalf of Nicolai Hähnle via llvm-dev" <llvm-dev-bounces at lists.llvm.org on behalf of llvm-dev at lists.llvm.org> wrote:
>
>    External email: Use caution opening links or attachments
>
>
>    On Tue, Jun 16, 2020 at 10:35 AM Momchil Velikov via llvm-dev
>    <llvm-dev at lists.llvm.org> wrote:
>> My 2 pennies is braces add unnecessary clutter and impair readability
>> when used on a *single-line* statement. I count comments, that are on
>> their own line as statement(s).
>
>    +1 for this. I think braces around single-line statements can be
>    allowed, but they really shouldn't be mandated, and that's been my
>    personal policy for reviews. In particular,
>
>      if (!is_transform_applicable) {
>        return {};
>      }
>
>    is very aggravating clutter.
>
>    Braces should be required around multi-line statements. Note:
>
>    BAD:
>      for (...)
>        for (...)
>          single_line_statement;
>
>    GOOD:
>      for (...) {
>        for (...)
>          single_line_statement;
>      }
>
>    Cheers,
>    Nicolai
>    --
>    Lerne, wie die Welt wirklich ist,
>    aber vergiss niemals, wie sie sein sollte.
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