saveAs gives misleading exceptions

[sbenthall]

using saveAs, I've gotten an HDF5LibraryException even when load works fine.

I made two changes and it fixed the problem:

• adding a .mat to the file name
• creating the directory that I was telling it to save into so that it gets a valid path

There's nothing blocking, but wanted to post an issue because there may be a more helpful way to do error reporting here. Since the HDF5LibraryException seems to be related to a wide variety of possible problems (including not having LD_LIBRARY_PATH set properly), it would be nice for usability to catch it and report a more specific error when possible.

[eternia478]

Hm, well, it might be even better to just have it create the folder (well, with an option, i.e. -f or something). The fact that it isn't named as *.mat though, should have a check that automatically adds it to the end.

[jcanny]

I agree with all of this, but the problem is that HDF5 I/O is implemented using an external C library and java wrapper. We inherit the error reporting from there. Its quite difficult to fix externally, although for some things (e.g. missing files or directories) we could add an external check.

I'll leave the issue open, and given enough time, or enough complaints, we'll try to fix it later.