[cfe-dev] [PATCH] Fixit for incorrect includes

[David Blaikie]

On Tue, Jul 17, 2012 at 11:01 AM, Aaron Ballman <aaron at aaronballman.com> wrote:
> On Tue, Jul 17, 2012 at 12:55 PM, David Blaikie <dblaikie at gmail.com> wrote:
>> On Tue, Jul 17, 2012 at 10:48 AM, Aaron Ballman <aaron at aaronballman.com> wrote:
>>> On Tue, Jul 17, 2012 at 12:10 PM, David Blaikie <dblaikie at gmail.com> wrote:
>>>> On Tue, Jul 17, 2012 at 9:14 AM, Aaron Ballman <aaron at aaronballman.com> wrote:
>>>>> This patch creates a fixit for include directives where the file could
>>>>> not be found when using angle brackets, but can be found when using
>>>>> quotes.  The converse is not needed since quoted includes will search
>>>>> angle bracket locations by default.
>>>>>
>>>>> Eg)
>>>>> #include <header.h>  // can be found via #include "header.h" instead
>>>>>
>>>>> Thoughts?
>>>>
>>>> Seems like a neat idea to me - but I'm not an authoritative sign-off.
>>>>
>>>> You used NULL as null constants for 2 of the conditional operators,
>>>> then 0 for the third - that seems inconsistent. You might want to
>>>> check what the prevailing style is in this file & stick to that
>>>> (generally in LLVM, '0' seems to be winning as the authoritative null
>>>> pointer constant, I believe).
>>>
>>> Easy enough to rectify (I'll standardize on 0) -- this was a copy from
>>> above, so I'll fix up there as well.
>>>
>>>> Did you consider adding this case to the existing fixit testing files?
>>>> They're already a grab-bag of things that can be fixed (this helps
>>>> keep the test suite fast by not adding more separate test file
>>>> executions) & this seems like it'd be at home there.
>>>
>>> I thought about it, but it strikes me as different enough to warrant
>>> its own test case.  Specifically, the fixit behavior is kind of
>>> tricky.  Because the fixit writes out a separate file, but in a
>>> different directory, I have to be a bit sneaky otherwise the header
>>> file isn't available.  This is because the temp file goes to the
>>> Output directory, but the header file remains in the FixIt directory.
>>> To work around this, I copy the testcase to a temp file, modify the
>>> testcase file directly with the fixit,
>>
>> Why can't you modify the temp file directly instead? (& you'd have to
>> copy the header over too, I suppose - you can identify the temp
>> directory with %T which means you can copy to fixed name files if
>> that's important (as it would be for the header name): %T/foo.cpp or
>> whatever)
>
> You learn something new every day!  I didn't realize you could use %T
> for the temp directory.  Now the testcase looks like:
>
> // RUN: %clang_cc1 -fsyntax-only -verify %s
> // RUN: cp %s %t
> // RUN: cp %S/fixit-include.h %T
> // RUN: not %clang_cc1 -fsyntax-only -fixit %t
> // RUN: %clang_cc1 -Wall -pedantic %t
>
> Which is cleaner (to me).  Thanks!
>
>> & yeah, arguable whether the existing fixit cases should be burdened
>> with this mucking about - I don't mind too strongly either way.
>
> Since include errors are fatal,

This actually raises a good question/point: when Clang encounters
fatal errors it basically stops, right? (it doesn't produce more
diagnostics) That's incorrect if we've provided a fixit and recovered
from the error - when fixits are provided we should recover as if the
code were written that way. With your change as it stands we
"successfully" apply fixits for this code:

#include <non_existent.h>
int main(float) {
}

because we didn't provide the error about main. What we should get is
the error about main and no fixit application because we encountered
an unfixable error.

> I figured this was a clean separation.
>  I'm not strongly tied to it though.
>
> New patch attached.
>
> ~Aaron