Improve error message returned by LoadAscii (and maybe other Load...)

[Federico M Pouzols]

This ticket is very similar to #9248 (which was about LoadNexusMonitors).

If you try to load for example UsageData/ls5637.mat you'll get a cryptic log message:

Error in execution of algorithm LoadAscii:
All arguments to init must be positive and non-zero

This can be very misleading to users. It would be very simple to provide a more informative error message to avoid confusion. Check also what happens with other Load... algorithms.

[Federico Montesino Pouzols]

add exception catches and better error msgs, re #10722

Changeset: 59f3b733fc51c7e87e1afa565585e3f024b4e9b2

[Federico M Pouzols]

This just adds a few checks and more informative error messages if the file cannot be loaded.

I checked other load algorithms for common formats, like loadAscii, loadNexus, etc. and apparently all of them come with at least some basic checks and error messages.

To test: use LoadAscii to load files that are definitely not ascii, or that could be interpreted as ascii/text files but are not in the correct format. Check that you get a more informative error message now. Tests should pass.

[Federico Montesino Pouzols]

Fix typo after merge conflict fixes, re #10722

Changeset: db247e43e50a7cee85c4cbf7acd5bd21aa938246

[Wenduo Zhou]

There are two places of conflicts as I merge branch into master. Please merge this branch with up-to-date master.

[Federico M Pouzols]

Re-merged with master.

[Federico Montesino Pouzols]

Merge branch 'master' into feature/10722_better_errors_loadascii_and_others

Conflicts:

Code/Mantid/Framework/DataHandling/src/LoadAscii2.cpp

Sorting out conflicts in merge with master, no issue apparently

Full changeset: ​723213cc02c53c028f2b9403d82c170feb95f685

[Wenduo Zhou]

Merge remote-tracking branch 'origin/feature/10722_better_errors_loadascii_and_others'

Full changeset: ​8684281dc9b05c71ed294d788ec71c223fdeb38a

[Wenduo Zhou]

The error message is helpful. Ticket is then close.

[Nick Draper]

Somehow these slipped through without a resolution. Set to Fixed.

[Stuart Campbell]

This ticket has been transferred to github issue ​11564