River Flow Control (Server)

A companion mod for Rivers. Requires Rivers to be installed. Server-side only — players install nothing and there is no version for them to match.

The problem

Setting disableFlow: true in Rivers' config does not stop boats drifting. It looks like it works for whoever is driving, and then someone watches an unattended boat sail off downriver.

Rivers applies its current as a Harmony patch category called "flow", and Patch() runs on both sides. That category is not only rendering — it also patches EntityBoat and PModuleInLiquid, which is the physics that actually pushes things downstream.

The only thing that ever switches it off is RePatchFlow(), which unpatches the category when the static ClientFlowDisabled is true. But that flag is assigned in exactly one place: OnSpeedMessage, a client packet handler. Server-side it stays false forever, so RePatchFlow() is a no-op there.

So disableFlow only ever produces a packet asking clients to unpatch themselves. The server keeps its own flow patches and keeps pushing entities, no matter what the config says. Whether a boat drifts then depends on which side is simulating it, which is why it looks intermittent.

What this does

Sets the flag on the server and calls Rivers' own RePatchFlow(), so the flow patches come off the server too.

• Reads Rivers' own ModConfig/rivers.json — there is no second setting to keep in sync. Set disableFlow there and it is enforced. Leave it false and this mod stays out of the way.
• Re-applies on a timer, because Rivers re-runs Patch() on several paths.
• Pure reflection, with no compile-time reference to Rivers. If a future version renames something, this logs a warning and leaves your server running rather than breaking it.

It logs plainly what it did:

[RiverFlowServer] server river flow forced OFF (was False) - EntityBoat and PModuleInLiquid unpatched

Do I also need the client mod?

Usually not. Rivers already broadcasts the setting to each player on join and their client unpatches itself. This fixes the half that nothing was fixing. My separate River Flow Control forces the client side as well, if you want belt and braces.