Bump the minimum pybind11 that we need

[lgritz]

Recent changes (2347) seem to rely on some pybind declarations that
are newer than the minimum version we checked for. Bump the pybind11
required version.

[lgritz]

Did this work, @sobotka ?

[sobotka]

Checking now. Hold tight.

[sobotka]

@lgritz clean cmake directly to your lg-oiio repository using the lg-pybind11 branch still seems to bomb out.

Topmost error:

[ 95%] Building CXX object src/python/CMakeFiles/PyOpenImageIO.dir/py_colorconfig.cpp.o
In file included from /lg-oiio/src/python/py_colorconfig.cpp:31:
/lg-oiio/src/python/py_oiio.h: In function ‘bool PyOpenImageIO::py_buffer_to_stdvector(std::vector<T>&, const pybind11::buffer&)’:
/lg-oiio/src/python/py_oiio.h:267:36: error: no matching function for call to ‘pybind11::buffer::request() const’
     oiio_bufinfo binfo(obj.request());

[lgritz]

Can you send me the full verbose output of a fresh build from scratch? If you use the makefile wrapper:

make nuke ; make | tee build.log

[lgritz]

Sorry, I meant:

make nuke ; make VERBOSE=1 | tee build.log

[lgritz]

It's not enough just to install the patch, you need to start from the initial cmake config step in order to get it to download the right pybind11 version.

[sobotka]

Trying another clean directory cmake build. Will ship log if error.

[lgritz]

That can't be the whole thing, it doesn't show the cmake config or generation steps at all.

[sobotka]

Replacing

    if ((BUILD_MISSING_PYBIND11 AND NOT PYBIND11_INCLUDES) OR BUILD_PYBIND11_FORCE)

with

    if ((BUILD_MISSING_PYBIND11 AND NOT PYBIND11_FOUND) OR BUILD_PYBIND11_FORCE)

in pythonutils.cmake fixes this, as per @lgritz

[lgritz]

Yes, Troy and I had a long off-ticket conversation. There was a bug, as cited above, where if you had pybind11 on your system but it was too old a version, it wouldn't do the auto-download like it was supposed to (and like it did, when it didn't find any pybind11 on your system).

I will amend the PR with that fix.

[lgritz]

Amended...

Fix logic in pybind11 auto-download:

If no pybind11 was found on the system, it would correctly auto-download.
I botched the test where, if a pybind11 was found but was an insufficient
version, it would not auto-download as intended. This was just an incorrect
test of PYBIND11_INCLUDES when it should have tested PYBIND11_FOUND.

I also augmented the logic to print a more helpful message pybind11
is found but is insufficient version, and furthermore if it's found
in the ext/ area (the auto-downloaded one) but still too old, it will
remind you that it needs to be blown away and refreshed. You'll see
something like this in the cmake configure output:

-- Pybind11 was found in /Users/lg/code/oiio/oiio.lg/ext/pybind11/include
-- ... but was version 2.4.0 (minimum is 2.4.2)
-- Try removing ext/pybind11 and let me download a newer version.