Install _compat.h

[jamesjer]

The headers cPersistence.h and ring.h are listed in headers in setup.py, but _compat.h is not, so it is not installed like the others. This is a problem because cPersistence.h has this on line 18:

#include "_compat.h"

The missing header causes the BTrees build to fail.

[jamadden]

As near as I can tell, this library has never installed the _compat.h header as such, even back when the first standalone release, 4.0.0, was made.

persistent/setup.py

Lines 64 to 65 in c9272cb

	headers = ['persistent/cPersistence.h',
	'persistent/ring.h']

It is included as data installed alongside the .py files, though. Typically, that's the directory that winds up on the compiler command line. E.g., on my Raspbian box, I see BTrees compile with -I/<path-to-venv>/local/lib/python2.7/site-packages. BTrees includes persistent/cPersistence.h, which is next to persistent/_compat.h in that directory.

BTrees also ships with its own _compat.h header, and because of the use of unqualified paths in the #include lines, that's the one that should be used when compiling BTrees. I don't recall the vagaries of C include file order right now, but even if that one is picked up first before persistent/_compat.h when reading persistent/cPersistence.h I think that'd be ok: We get "lucky" in that the BTree version is a superset of the persistent version (as far as other .h files are concerned).

I had no trouble installing persistent 4.6.1 from source from PyPI and then installing BTrees 4.6.1 from source from PyPI (on 32-bit Raspbian arm just to be sure).

Maybe it would help if you could provide more details about the failure you're seeing.

[jugmac00]

Maybe that's related to https://community.plone.org/t/valueerror-need-more-than-0-values-to-unpack-ploneintranet/5771/9 ?

[d-maurer]

Jürgen Gmach wrote at 2020-3-8 05:51 -0700:

Maybe that's related to https://community.plone.org/t/valueerror-need-more-than-0-values-to-unpack-ploneintranet/5771/9 ?

It is unrelated: Here, apparently "_compat.h" is not found; there "_compat.h" has been found but its "Python.h" include failed (because the Python installation was binary only lacking development resources like "Python.h").

[jugmac00]

Thanks Dieter. Maybe it's about time for me to learn at least some basic C.

[jamesjer]

Thanks for the helpful information. It turns out that the way I had been injecting "-IBTrees" in to the build flags for the C compiler stopped working, leading to the compiler's inability to find _compat.h. I fixed that issue and BTrees builds fine again. Sorry for the noise. Let's close this.