t_pyLCIO_import test broken on some systems

[tmadlener]

The t_pyLCIO_import test seems to be broken (at least partially). See, e.g. the CI workflow outputs of #132: e.g. centos

I can reproduce this locally on Ubuntu as well

• OS version: Ubuntu 20.04
• Compiler version: GCC 9.3
• Package version: master
• root version: 6.22/08

[tmadlener]

This is because of the following loading logic:

LCIO/src/python/pyLCIO/base/SetupLcioDictionary.py

Lines 16 to 31 in 8f9e86b

	lcioPath = os.environ.get( 'LCIO' )
	if not lcioPath:
	print('Environment variable $LCIO is not defined!', file=sys.stderr)
	sys.exit( 2 )
	if not os.path.exists( lcioPath ):
	print('LCIO path %s does not exist' % (lcioPath))
	sys.exit( 2 )
	liblcioPath = os.path.join( lcioPath, 'lib', 'liblcio.so' )
	# See http://root.cern.ch/root/html/TSystem.html#TSystem:Load for error codes
	result = gSystem.Load( liblcioPath )
	if result not in [0, 1]:
	print('Error loading %s' % (liblcioPath), file=sys.stderr)
	sys.exit( 2 )
	liblcioDictPath = os.path.join( lcioPath, 'lib', 'liblcioDict.so' )
	# See http://root.cern.ch/root/html/TSystem.html#TSystem:Load for error codes
	result = gSystem.Load( liblcioDictPath )

This logic only works if LCIO is installed back into its source directory, because it implicitly assumes where the libraries should be located and tries to load them via a full path. However, this is not strictly necessary, as ROOT will look on LD_LIBRARY_PATH in any case if just the library name is provided.

[gaede]

Yes, we have in principle always made in-source installations for LCIO and iLCSoft releases. This is exactly the kind of stuff, we'd have to fix across all packages when modernizing the cmake...

[tmadlener]

But even with the in-source installation the LD_LIBRARY_PATH points to the correct lib (or lib64) directory, right? So the lookup would not need to depend on the way things are installed as long as LD_LIBRARY_PATH is set correctly.

[gaede]

Yes, this was just meant as an explanation, why it was done that way. Please feel free to change as needed...

[tmadlener]

OK. Very good, I just wanted to make sure my assumption about the LD_LIBRARY_PATH is correct. In #136 I have made the lookup such that we first try to use ROOT and its automatic loading via LD_LIBRARY_PATH, before we fall back to the in-source installation lookup logic.

As a nice side-effect this makes this test independent of the way LCIO is installed (or would be installed) and now all tests can be run without installing first.