Three sprints and a conduit

This is Apoli 1.92.0 and Origins 1.42.1: three bugs about sprinting and water, and a conduit that finally earns its place in an Origins world.

An anchor, not a water walker

The report was vivid. With Sable installed, a walk_on_fluid origin doesn't walk on water. It sinks to the seabed and can't swim back up. You become an anchor, only able to move deeper into the ocean.

apoli:walk_on_fluid never adds a shape. It answers a question the fluid block asks during collision, whether the entity colliding with it can stand on this fluid, and a source block that hears "yes" hands back a solid top surface. Vanilla asks that question with two fluids, the one above the block and the block's own. It tests the entity against the block's own fluid, and only uses the one above to check that it isn't more of the same fluid, which is what stops you standing in the middle of a lake.

Sable swaps in its own collision context for every entity in the world, and its version tests the entity against the fluid above. Above an ocean surface is air, an entity can't stand on air, and the surface stops existing.

That alone would just drop you in the water. What makes you an anchor is the other half of walk_on_fluid: the same "can you stand on this?" answer also decides whether you swim or walk. Standing on water means walking, and someone walking in the ocean has no swim stroke, no water drag and full gravity. Down you go.

Apoli now asks the question again the vanilla way whenever a source fluid block would otherwise return nothing, and only when Sable is installed, so a world without it keeps the normal collision path untouched. Striders on lava were broken the same way, and the same hook fixes them.

prevent_sprinting now prevents sprinting

apoli:prevent_sprinting parsed, loaded, showed up in the power list and did nothing at all. It had a codec and no implementation. Now it has one, in two places. Any setSprinting(true) on a living entity is turned into a stop, so a sprint in progress ends instead of only failing to start again, and the client's own "can I sprint?" check answers no, so the sprint never starts and no packet is sent. A sprint packet that arrives anyway is refused on the server.

It works on any living entity now, not only players.

Flying isn't a meal

A smaller thing, found while testing something else: a player with apoli:creative_flight could sprint at zero hunger, and an ordinary origin couldn't.

That's vanilla. The client's sprint check reads "more than 6 food points, or you may fly", so any source of flight is also a source of endless sprinting. That shortcut exists for creative mode, where hunger is frozen anyway. It was never meant as a perk you could hand out in survival.

Apoli now keeps the shortcut for actual creative and spectator mode and takes it away from flight granted by a power. A survival origin that flies still has to eat.

Conduits, for the origins that hate water

Origins 1.42.1 rebalances Hydrophobia and gives the conduit two jobs.

For the Enderian and the Blazeborn, Water Protection now behaves like the enchantment it looks like. It slows the damage down and softens it, and it never cancels it. Each combined level across the four armour slots adds 0.3 seconds to the gap between hits, up to 8 levels (2.4 seconds on top of the base second), and takes 4% off each hit, up to 16. A full set of Water Protection IV turns a 1 heart hit every second into a 0.36 heart hit every 3.4 seconds. The delay stops improving halfway up and the reduction doesn't, which is what makes the second half of the set worth wearing.

The 4% is vanilla's own curve, damage × (1 − points / 25). Sixteen points out of a possible twenty-five is as far as it goes, so zero is out of reach by construction, with no clamp needed.

What it doesn't do any more is grant immunity. Standing in an active conduit's field does: while minecraft:conduit_power is on you, water and rain stop hurting entirely. Rain and water are exactly the conditions vanilla applies conduit power in, so the two line up without any extra plumbing.

The reduction is applied by the power instead of by a minecraft:damage_protection effect on the enchantment, which looks like the long way round, so here's why. Water damage sits in #minecraft:bypasses_enchantments. An enchantment effect would need it taken out of that tag, and that would also hand the same 4% per level to plain minecraft:protection, at which point there's not much reason to go looking for the dedicated one.

For the Merling, the same block does the opposite favour. An active conduit now treats any entity that suffocates out of water as if it were in the water, and gives it Conduit Power on dry land anywhere in range: 32 blocks for the smallest frame that activates it, and 96 for a full one. Conduit Power already stops the suffocation, so a Merling with a conduit at their base can walk out of the sea and stay out, for as long as they stay inside the field. It's a build worth making, and a reason for a Merling to be on the shore with everyone else.

The whole Hydrophobia mechanic is still one power file per origin, documented field by field on the Water Protection page. Every number in it (the base second, the 0.3, the 4%, both caps, and which effect grants immunity) is a line you can edit.