Sort entries in StellarSDK.xdr.ScVal.scvMap(...)

[leighmcculloch]

According to this report:
https://discord.com/channels/897514728459468821/1183574303921418250/1321262080061476935

the StellarSDK.xdr.ScVal.scvMap(...) function currently does not sort the entries in the map.

The network requires them to be sorted, and as @Shaptic pointed out there are some functions that do sort the entries appropriately, but not this one it seems.

[Shaptic]

This is generated code and so we can't exactly control how "helpful" its behavior is. If you're coding at this level, unfortunately you've just gotta know exactly what you're doing.

Per your link, this code:

const milestonesScVal = milestones.map(milestone => {
        return StellarSDK.xdr.ScVal.scvMap([[
            new StellarSDK.xdr.ScMapEntry({
                key: StellarSDK.xdr.ScVal.scvSymbol(“description”),
                val: StellarSDK.xdr.ScVal.scvString(milestone.description)
            }),
            new StellarSDK.xdr.ScMapEntry({
                key: StellarSDK.xdr.ScVal.scvSymbol(“status”),
                val: StellarSDK.xdr.ScVal.scvString(milestone.status)
            }),
            new StellarSDK.xdr.ScMapEntry({
                key: StellarSDK.xdr.ScVal.scvSymbol(“flag”),
                val: StellarSDK.xdr.ScVal.scvBool(false)
            })
        ]);
    });

Could instead be written as

const milestonesScVal = milestones.map(milestone => {
    return nativeToScVal({
        description: milestone.description,
        status: milestone.status,
        flag: false
    }, {
        type: {
            description: [ "symbol", "string" ], 
            status: [ "symbol", "string" ],
            flag: [ "symbol" ]
        }
    })
});

And the map keys will be sorted correctly. We built helpers for a reason :D

[leighmcculloch]

Someone might want to build with the xdr types though, as we saw reported in Discord, which is reasonable.

Could we add StellarSDK.xdr.ScVal.scvMapSorted that does the same thing but sorts the entries?

[Shaptic]

Not there because the ScVal structure is generated. I could inject it into xdr, though.

I'd again argue that if they are digging so deep into the codebase that they're building structures from scratch, they should understand the ordering requirement. Especially since maps aren't strongly typed, so there are plenty of non-trivial sorting cases that an algorithm can't resolve. Or just... use the helpers 😆

Anyway, I added best-effort sorting in stellar/js-stellar-base#787.