[FFmpeg-devel] [FFmpeg-cvslog] ffbuild: use response files only if ar accepts them

[Gyan Doshi]

On 2025-03-20 05:39 am, Ramiro Polla wrote:
> On Tue, Mar 18, 2025 at 11:06 AM Gyan Doshi<git at videolan.org>  wrote:
>> ffmpeg | branch: master | Gyan Doshi<ffmpeg at gyani.pro>  | Mon Mar 17 20:57:28 2025 +0530| [740d4009656abeb006e2d43001b59d875c1a7a6a] | committer: Gyan Doshi
>>
>> ffbuild: use response files only if ar accepts them
> Sorry to come in late to the discussion...
>
> I'm not a big fan of response files, because they make troubleshooting
> more annoying (I like copying the command that failed and running it
> again on its own with all arguments). IMO this shouldn't be the
> default, but only used on systems where this could be a problem (i.e.:
> Windows). Also, only based on host systems, so not while
> cross-compiling from Linux.


I don't think most users want to log a ~30K character command for debugging.
How about an option, choices : yes, no, auto(default)?


> I was wondering why ld.exe/ar.exe fail with a long argument list, but
> echo doesn't. After a bit of investigation, it seems that cygwin/msys2
> pass arguments through STARTUPINFO::lpReserved2 and shared memory. But
> only programs built for cygwin/msys2 can make use of that, otherwise
> the parameters from CreateProcess() are used. So echo is a
> cygwin/msys2 program, but ld.exe/ar.exe are not. If, by any chance,
> you have a non-cygwin/msys2 echo.exe on your path, this will fail
> again.

I think this permutation of tools is low-probability but I have a 
workaround in mind, so I'll send that.


>> @@ -68,8 +72,12 @@ $(SUBDIR)$(SLIBNAME): $(SUBDIR)$(SLIBNAME_WITH_MAJOR)
>>
>>   $(SUBDIR)$(SLIBNAME_WITH_MAJOR): $(OBJS) $(SHLIBOBJS) $(SLIBOBJS) $(SUBDIR)lib$(NAME).ver
>>          $(SLIB_CREATE_DEF_CMD)
>> +ifeq ($(AR_OBJS),true)
>>          $(Q)echo $$(filter %.o,$$^) > $$@.objs
>>          $$(LD) $(SHFLAGS) $(LDFLAGS) $(LDSOFLAGS) $$(LD_O) @$$@.objs $(FFEXTRALIBS)
>> +else
>> +       $$(LD) $(SHFLAGS) $(LDFLAGS) $(LDSOFLAGS) $$(LD_O) $$(filter %.o,$$^) $(FFEXTRALIBS)
>> +endif
>>          $(SLIB_EXTRA_CMD)
>>          -$(RM) $$@.objs
> Is there any reason why we don't ifeq the removal of the response file as well?

The command result won't abort the script so I avoided inserting more 
guards.

Regards,
Gyan