[Plplot-devel] CMake version discussion

[Alan W. I. <ir...@be...>]

On 2017-10-06 11:00+0100 Phil Rosenberg wrote:

> I [...] spotted this bug report
> https://cmake.org/Bug/view.php?id=15831. I think the gist of it is
> that find_library will only search in Windows SDKs that are at least
> as old as the one used to build that version of Cmake. This seems a
> bit daft to me as it forces upgrade whenever a new SDK is released

Brad King refers in that discussion to the target version, but I
am not sure exactly what he means by that.  But what is clear from
that discussion is Brad felt the early SDK policy for Windows 10 was
wrong, and they instead adopted the same policy as is used for
Mac OS X and their SDK's which I assume is a rational one without
the need for forced CMake (or SDK) upgrades.  The implementation
of that fundamental change in policy was done by commit
<https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=a57caf7e>
where the new policy is summarized as

Select "a Windows 10 SDK if one exists.  Use the
SDK for the exact version if is available.  Otherwise use the latest
version of the SDK available because that will have at least the APIs
expected for the target version."

Does that policy (implemented in the run-up to CMake 3.4.0) appear
like a rational one to you?

> I
> know in the past Alan has mentioned the need to not upgrade due to a
> bug in a release.

I have said a lot of things in the past concerning CMake versions
because early versions of CMake-3.x.y truly sucked.  But my experience
with CMake versions between 3.6.2 and 3.9.x is much better.  My
attitude now concerning CMake versions is summarized in "1.1 CMake
version compatibility" which you can find for the recent 5.13.0
release in README.cumulated_release.

In sum, due to our extensive comprehensive testing of various CMake
versions, I feel most/all versions of CMake between 3.6.2 (our minimum
allowed version) and CMake 3.9.x should be fine.

Of course, the caveat to that summary is we have not comprehensively
tested PLplot for Windows SDK's, and there is still a lot of on-going
bug fixing for the various Windows SDK's by the CMake developers so I
think, in general, you would be better off using 3.9.4 than your
current 3.7.1.  Anyhow, why not try 3.9.4 and see? If it does not
satisfy your personal needs, then you can always move back to 3.7.1.
But the bigger issue as PLplot developers is we need to know about any
problems you might have with 3.9.4 and your particular Windows SDK so
we can make the appropriate bug reports to CMake to get the issue
fixed to protect _all_ our users in your situation.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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