Support for PROJ 6.0.0

[sebastic]

Mapserver still uses proj_api.h which is deprecated in PROJ 6.0.0 and will be removed in PROJ 7.0.0 (scheduled for March 2020).

When using proj_api.h with PROJ 6.0.0 -DACCEPT_USE_OF_DEPRECATED_PROJ_API_H=1 needs to be added to CFLAGS to prevent a compiler error.

Mapserver should be updated to (also) support the proj.h API.

Note that PHP MapScript still includes projects.h which is no longer available in PROJ 6.0.0.

[bmulcahy]

In the mean time a quick work around for anyone needing to use PROJ 6 or anyone who has recently built GDAL with PROJ 6 without realizing mapserver wasn't compatible, not saying that is what I did but just in case someone does.

Add

#define ACCEPT_USE_OF_DEPRECATED_PROJ_API_H 1
before line 41 in mapserver/mapproject.h

THIS IS NOT A SOLUTION just a work around.

[sdlime]

This should really be targeted for 7.4. @rouault, any feel for how big a deal this is likely to be?

[rouault]

any feel for how big a deal this is likely to be?

I haven't looked in details, but not trivial.
And I'm not sure we can keep PROJ <6 and PROJ >= 6 support at the same time.

[sdlime]

Thanks and ugh... I had this as a code sprint activity for 8.0, perhaps it's best left there. Will start reading up.

[fxcoudert]

Currently blocking integration of latest proj in Homebrew: Homebrew/homebrew-core#38215

[sdlime]

@rouault is the preferred method to set a cflag -DACCEPT_USE_OF_DEPRECATED_PROJ_API_H=1 or the define in mapproject.h as suggested by @bmulcahy? They're equivalent and the latter is trivial (no messing with cmake) so I was going to add that quickly before creating the 7.4 branch. Just making sure...

[rouault]

or the define in mapproject.h

this is fine to me, but I also see that mapwcs20.c directly includes <proj_api.h>. I guess that include should be replaced by mapproject.h (or it is possible that mapproject.h is indirectly included)

[sdlime]

mapproject.h is included in mapserver.h which is also included in mapwcs20.c so I think we're ok. It looks like mapwcs20.c is only using the pg_is_latlong() function/macro...

[sebastic]

What about PHP MapScript? It still uses projects.h in 7.4.0-beta1.

[sdlime]

What about PHP MapScript? It still uses projects.h in 7.4.0-beta1.

Will have to address in beta2...

[sdlime]

@sebastic, I made a small change in PHP/MapScript with the workaround. Any chance you could test on your end? --Steve

[sebastic]

I guess you mean commit b4b680d?

That won't suffice, because projects.h is still used (and is no longer available in PROJ 6.0.0), php_proj.c needs to be ported to use proj_api.h instead. And possibly also the two methods in map.c.

[rouault]

That won't suffice, because projects.h is still used (and is no longer available in PROJ 6.0.0), php_proj.c needs to be ported to use proj_api.h instead

I'd suggest completely dropping php_proj.c . This has nothing to do mapserver itself. This is a PHP binding to PROJ old projects.h. There's no way to emulate completely with new API since this is really a raw bindng to projects.h function. And we could drop it since it doesn't seem to be used elsewhere in the PHP bindings.
Actually it isn't even in CMakeLists.txt ! So the file should be removed
@sebastic Do you have actual build issues related to it ?

And possibly also the two methods in map.c.

From what I see, they use mapserver abstracted API and don't depend explicitly on PROJ headers

[sebastic]

@sebastic Do you have actual build issues related to it ?

No, MapServer 7.4.0-beta1 builds successfully with PROJ 6.0.0.

[rouault]

Support for proj.h API has been added in master a few weeks ago per #5888