Re: [PATCH] cmake: ignore generated files

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Junio,

On Wed, 23 Sep 2020, Junio C Hamano wrote:

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>
> >> > The change that Dscho suggested was meant for those people that run
> >> > CMake in same directory of source dir, which is mostly discouraged
> >> > in CMake land.
> >
> > It is discouraged, but not disallowed.
> > ...
> >> > I think the original CMake proposal didn't touch .gitignore because
> >> > they run in a separated build-dir.
> >>
> >> If so, not only my "do we need a matching change to CMakeLists to
> >> teach how to clean crufts?" becomes unnecessary, but the original
> >> patch that started this thread to touch .gitignore at the top level,
> >> does, too.
> >>
> >> I wonder what led Dscho not to follow the "create a 'build' dir and
> >> do things there" practice.  Judging from the fact that the "because
> >> they run in a separate build directory" assumption did not hold to
> >> somebody as experienced as Dscho, it is likely others would do the
> >> same.
> >
> > That's because Dscho does not like the separate build directory, even if
> > they know that in the CMake world, it is kind of expected.
>
> Sorry, but that does not sound like a convincing excuse because ...
>
> > It's just that it would be super convenient for Visual Studio users to
> > just generate their project files in-place. That's why I started down that
> > road.
> > ...
> > Ideally, we would tell Visual Studio users to "just install CMake, start
> > its GUI, direct it to the Git source, configure and generate". Alas, it is
> > not that easy:
> >
> > - The `SH_EXE` is not found by default (`C:\Program Files\Git\bin\sh.exe`
> >   should be used in the vast majority of the cases),
> > - If the build directory is left unspecified, the non-writable `C:\Program
> >   Files\CMake\bin` directory is used,
> > - The `compat\vcbuild\vcpkg` system is not initialized automatically, and
> >   even if the user initialized it, the dependencies (such as expat, zlib)
> >   are still not found.
>
> ... if the build directory needs to be specified anyway, there don't

It doesn't need to be specified.

> seem to be a big difference between telling them to create an empty
> build place and use it and telling them to point at the source tree
> itself, so ...
>
> > I would like to make things easier, and forcing users to use a separate
> > build directory (that needs to be outside of the Git source tree because
> > our `.gitignore` does not handle it well) would go the other direction, I
> > fear.
>
> ... the above sounds like the argument concentrates too much on
> where the build directory is (i.e. between "in place" and "a
> throw-away directory next door"), which sounds like much smaller
> point compared to the other things that needs to be improved in the
> VS users.  And making a choice against what is recommended as best
> practice...?  I dunno.

All I want is for the CMake support to be easier to use, yet we go in the
opposite direction: instead of allowing to use CMake under more
circumstances (which actually *works*, we just don't have the appropriate
patterns in our `.gitignore` yet to avoid adding and committing the
generated files), we now seem to intend to require a separate build
directory.

That's the opposite direction of making things more convenient for Visual
Studio users.

Ciao,
Dscho