[cmake-developers] To warn or to error out ? - wording and compatiblity

[David Cole]

On Tue, Nov 1, 2011 at 5:58 AM, Alexander Neundorf <neundorf at kde.org> wrote:
> Hi,
>
> when using out-of-source builds and the Eclipse CDT project generator, a
> "linked resource" is created in the Eclipse project file, which points to
> CMAKE_SOURCE_DIR, so the user can browse the source directory.
>
> Now, when CMAKE_BINARY_DIR is a subdirectory of CMAKE_SOURCE_DIR (e.g.
> MyProject/build/ ), such a "linked resource" can't be created, and the
> resulting project file still works, but is less usable.
>
> I just added a warning, so that cmake now says:
>
> "-- Configuring done
> CMake Warning in CMakeLists.txt:
>  The build directory is a subdirectory of the source directory.
>
>  This is not supported well by Eclipse.  It is strongly recommended to use a
>  build directory which is not a subdirectory of the source directory.
>
>
> -- Generating done"
>
>
> I'm thinking about using FATAL_ERROR instead of warning for this, since the
> resulting project file without that link really feels wrong, and I recommend
> everybody to not build in a subdir of the source dir.
>
> This would have the effect that a build dir which was working until now does
> not work anymore with the next cmake release, the user would have to create a
> new build dir in some other location.
>
> Would this be acceptable ?
>
> Alex
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I think a warning is good enough here.

I would phrase it in the positive sense, rather than in the negative
sense, though:

Rather than:

>  The build directory is a subdirectory of the source directory.
>
>  This is not supported well by Eclipse.  It is strongly recommended to use a
>  build directory which is not a subdirectory of the source directory.

How about "It is strongly recommended to use a build directory which
is a sibling of the source directory."