[cfe-dev] clang-format turning tests into no-ops

[Daniel Jasper]

On Thu, Nov 7, 2013 at 10:48 PM, Sean Silva <silvas at purdue.edu> wrote:

>
>
>
> On Fri, Nov 8, 2013 at 12:49 AM, Alp Toker <alp at nuanti.com> wrote:
>
>>  Hi Daniel,
>>
>> Here's a good one for you..
>>
>> I've recently been fixing a whole lot of lit tests in the LLVM / clang
>> suites that don't check anything.
>>
>> It was a mystery why people keep checking in tests like this:
>>
>> // RUN: clang-check "%s" -- -target x86_64-apple-darwin10 -fasm-blocks
>> 2>&1 |
>> // FileCheck %s
>>
>> The first line will run successfully, and the second doesn't begin with
>> RUN so the test passes silently. Not good.
>>
>> Then it dawned on me -- contributors must be running clang-format before
>> committing, causing their RUN lines to get split up at the line boundary.
>>
>> I know this isn't strictly a clang-format bug, but it's time consuming to
>> manually audit and find no-op tests like this after the fact and the
>> failure mode is insidious because these tests will always silently pass.
>>
>
> Although it doesn't eliminate the hassle of having to manually fix this,
> it seems like at least one issue worth fixing in its own right is the fact
> that RUN lines ending with a | are silently accepted by our test
> infrastructure.
>
> Also, FWIW, it seems like clang-format's comment reflowing turns out to do
> the wrong thing in a ton of (most?) scenarios (for example, it will wrap
> the last word onto the next line, leaving a bunch of spurious "one word"
> lines), to the point that I wish there were an option to tell clang-format
> to not mess with comments at all.
>

clang-format does not "reflow" yet. It just breaks a comment if it is too
long. We'll likely want a "reflow" option, but probably bound to a specific
"editor mode", so that clang-format does not mess up some person's
ASCII-art comment unless it is done in an editor and the result can easily
be undone.

FWIW, I consider a "spurious on word" comment better than a comment
violating the column limit, so I am quite strongly against just turning
comment breaking off.

-- Sean Silva
>
>
>>
>> I was wondering if you can think of a way to exclude the test suites from
>> clang-format and clang-format-diff runs. Guessing this could be tricky
>> given that there are several different ways to run clang-format but
>> something needs to be done..
>>
>> Alp.
>>
>> -- http://www.nuanti.com
>> the browser experts
>>
>>
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>>
>>
>
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