Dealing with (and debugging) package installation errors

[fingolfin]

Unfortunately it seems difficult to debug issues when installing a package using PackageManager fails, esp. packages that have compiled code. The reason for that is that the failed package is deleted, and with it all debug logs etc. For example, from gap-packages/NormalizInterface#96:

...
#I Running compilation script on /home/i/.julia/gaproot/v4.11/pkg/NormalizInterface-1.2.0 ...
#I Package availability test failed
#I (for NormalizInterface 1.2.0)
#I Removed directory /home/i/.julia/gaproot/v4.11/pkg/NormalizInterface-1.2.0

So... it seems it even compiled, but then failed to load. Replicating the problem can be difficult; in this case, I believe the package actually compiled correctly, but then there was an issue caused by the setting of the GAPROOTs. But I am not 100% sure, and since manually building the package worked, I have a hard time reproducing it.

So it would be nice if there was some facilities to help with that. E.g. an option to tell the PackageManager to not delete the package that was just compiled. Perhaps also some other things could be done, I am happy to discuss.

[fingolfin]

Perhaps there could be an option debug := true (say: InstallPackage("blah" : debug) which disables deletion of logs and incomplete packages. That shouldn't be too hard?

[fingolfin]

See #119 for a first draft on this

[mtorpey]

I've renamed the option to keepDirectory, and I've included it in doc and tests. Thanks!