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

[Aaron Ballman]

On Tue, Jul 17, 2012 at 1:10 PM, David Blaikie <dblaikie at gmail.com> wrote:
> 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'm not actually recovering with my patch -- I'm still early returning
out of HandleIncludeDirective.  So if this is possible to "fixit",
does that mean this really shouldn't be a fatal error in this case?

~Aaron