Fixed : don't crash when stat graph setting is broken

[kevin-frugier]

For some reason, after returning to ForestAdmin UI after a while, some settings of my graphs were broken without having changed anything.

That's a bummer in itself (why did ForestAdmin loose my config out of the blue?), but the real problem is that this case was not properly handled by forest-express-mongoose hence resulting into a crash of my app.

error: UnhandledRejection: exception: $sort must have at least one sort key error: MongoError: exception: $sort must have at least one sort key error: Node app stopping. [forest] 🌳🌳🌳 exception: $sort must have at least one sort key 

The change of line-stat-getter.js fixes the crash.
The change of pie-stat-getter.js changes the cryptic
[forest] 🌳🌳🌳 Cannot read property 'reference' of undefined
into
[forest] 🌳🌳🌳 Missing param `group_by_field`

None of that would be required if the graph setting never broke for no reason (it's indeed impossible to create a graph without proper settings).

[arnaudbesnier]

Hi @kevin-frugier, I am not a big fan of the idea of hiding the Forest issue you pointed by adding protections on the liana.

The best for us would be to have a simple way to reproduce your charts "destruction" and then fix this issue. Do you have any reproduction steps?

Thanks!

[kevin-frugier]

Hi @arnaudbesnier,

Personally I'm not a big fan of an update of Forest crashing my PRODUCTION server either.
But it doesn't mean both sides can't be reinforced.

Anyway the liana is already quite robust to failures because it doesn't crash on exceptions.
It currently crashes on unhandledRejection which is what I prevent with the fix of line-stat-getter.js (I prevent the rejection to be raised in the first place).
You could simply handle unhandled rejections the same way you handle exceptions if you don't want to fine tune every bits of (potentially) broken code.

As for reproduction steps, the only thing I can tell you is that I migrated from Node 0.10.46 to 6.9.5 (at last!) but none of the model declaration has changed and the graph anyway is not declared at all on the serverside (only in Forest) and uses standard data.

Luckily, it's during the validation phase of this migration (to 6.9.5) that I noticed that Forest had lost some of my graphs settings (like 'group_by').

[roopakv]

would actually love if there was some progress on this.