[Geany-Devel] Ping on Bug #943 - windows build command

[Matthew Brush]

On 13-10-07 08:31 AM, Nick Treleaven wrote:
> On 05/10/2013 15:40, Matthew Brush wrote:
>> On 13-10-05 07:06 AM, Nick Treleaven wrote:
>>> On 05/10/2013 14:59, Nick Treleaven wrote:
>>>>> I don't remember seeing any bug reports for this, so it's possible
>>>>> it's
>>>>> limited to you or the specific application you were using, maybe a bug
>>>>> in a certain version of DMD? The commit messages doesn't explain what
>>>>> the actual root of the problem was or why it could not be fixed
>>>>> properly, or what was tried to fix it before abandoning the existing
>>>>> code.
>>>>
>>>> It was last year, but I think it wasn't just with dmd, although that
>>>> triggered it the most, and it only happened when dmd wrote more than a
>>>> certain amount to stderr (cascading errors). It was very suspicious
>>>> that
>>>> the custom spawn code works until there are too many errors, at least
>>>> with dmd.
>>>
>>> One person reported it on the devel list. See:
>>> http://lists.geany.org/pipermail/devel/2011-July/004845.html
>>>
>>> Unfortunately I missed that mail at the time, but I tried the provided
>>> fix before committing my system() change, and I remember it didn't fix
>>> all the issues with blocking and/or hanging Geany I had.
>>>
>>
>> That was going to be my guess for the deadlock, once the buffers fill up
>> they have to be drained or else can't keep writing to input. The same
>> issue should apply to any spawning method we use probably (ie. GSpawn).
>
> Did we get deadlock with g_spawn? I'm only aware of missing output.
>

It sounded like what was described by Josh in your link:

"The problem seems to be that pipes are only 4kb buffered by default, 
so any process needing to write more than this would block while writing 
to stdout and Geany would kill it, as it wasn't reading the pipes until 
after the process exited."

>> So with the pull request adding system() as a fallback/hidden
>> preference, maybe we could just drop the win32 API code altogether,
>> switch back to using the same codepath as all platforms (ie. GLib async
>> spawning) and if people experience issues, we can use as further data
>> points to troubleshoot GLib async spawning and we can recommend they try
>> the system() option[1] as a workaround?
>
> system() is *synchronous*, so we couldn't remove the SYNC_SPAWN code and
> have it as an option.
>

I mean to remove the win32_spawn function (as it existed before the 
system() hack), the one that was left orphaned in win32.c and renamed it 
to broken_win32_spawn() that uses the win32 API rather than GLib 
spawning or system().

>> IMO, any function in our code base prefixed with _broken, that no one
>> wants to touch, and looses platform-independence for our code, should
>> just be deleted[2] :)
>
> I thought you said it was most important to fix the common case, that's
> why I made the PR.
>

I imagine the most common case would be that g_spawn_async_with_pipes() 
works. I've used it a number of times on Windows without issues and I've 
not found online or encountered any issues with lost output that's being 
claimed as the reason for all these work-arounds for it.

>> BTW, did you try undefining SYNC_SPAWN lately to see if async spawning
>> still doesn't work for you now? If so and it doesn't, what Windows
>> version and GLib versions do you have?
>
> I just tried it. Running build on a C file:
>
> gcc -Wall -c "build.c" (in directory: C:\git\geany\src)
> Compilation failed.
> gcc: error: "build.c": Invalid argument
> gcc: fatal error: no input files
> compilation terminated.
>
> No idea why gcc says that, also tried for another file in parent directory.
>
> Running build on a D file just says 'Compilation failed' without
> reporting the line compilation fails on.
>
> Windows Vista. GTK 2.22.0, GLib 2.26.0.
>

GTK+ 2.22 is over 3 years old by now, FWIW.

Cheers,
Matthew Brush