Pumpkin

This is caused by an NBT serialization bug in Pumpkin 0.2.0+26.3–26.51. MapDecorationsImpl uses the default DataComponentImpl::write_data, which emits NbtTag::End (0x00) for minecraft:map_decorations instead of TAG_Compound (0x0A). The invalid NBT makes the chunk unreadable on reload, so Pumpkin regenerates it and destroys block entities.

Fix: update Pumpkin to a build containing the fix(data): prevent map decoration NBT corruption change, where map_decorations is written as a compound tag.

Workaround on affected versions: back up the world, then remove the minecraft:map_decorations component from every item before serving it with Pumpkin. The actual map image is not lost because it remains in data/minecraft/maps/*.dat and is referenced by the correctly serialized minecraft:map_id component. Chunks already regenerated must be restored from a backup; their block entities cannot be recovered from the overwritten region file.

In Pumpkin, set use_tty = false in the [commands] section of pumpkin.toml, then restart the server:

[commands]
use_tty = false

This fixes the issue where the first command is not executed and each command runs only after the next one is sent. The problem is caused by a TTY handling bug in the Rustyline dependency; the upstream fix exists in commit f2bbcc5 but was not yet included in a released version when the issue was reported.

The crash is caused by unbounded recursive neighbor/shape block updates. Large groups of saplings, pressure plates, and similar self-breaking blocks propagate updates recursively until the worker stack overflows. Update your server to a build containing the fix that processes neighbor updates through a bounded iterative work stack. As a workaround on affected versions, split the fill into smaller volumes, for example 16×16×1 layers instead of 16×16×16:

/fill ~ ~ ~ ~15 ~ ~15 minecraft:acacia_sapling
/fill ~ ~1 ~ ~15 ~1 ~15 minecraft:acacia_sapling
/fill ~ ~2 ~ ~15 ~2 ~15 minecraft:acacia_sapling

Continue incrementing the Y coordinates until the full volume is filled. Avoid filling more than roughly 512–576 sapling or pressure-plate blocks in one command until patched.

This is caused by the leaf decay logic calling world.break_block(...), which triggers block-break sound and particle effects. Decaying leaves should use world.set_block_state(...) so they are removed silently, matching vanilla behavior. The fix was introduced in commit 742beaf6f9f84fb99a04402434f6c6feb86667d1; update your server to a build containing PR fix(block): don't play break effects when leaves decay. If maintaining a fork, replace the leaf-decay world.break_block(...) call with world.set_block_state(...).

This affects Pumpkin Java Edition builds 0.2.0+26.3 through 26.51. When the portal is lit from a side obsidian block, NetherPortal::create places portal blocks without vanilla's UPDATE_KNOWN_SHAPE flag, causing mid-build neighbor updates to remove the igniting fire and some portal blocks.

Fix: update Pumpkin to a release or build containing the PR fix(portal): write nether portal blocks without neighbour shape updates, which fixes issue #3839, then restart the server and relight the portal.

Temporary workaround: use flint and steel on the bottom/floor obsidian block of the portal instead of a side or vertical face. Remove any leftover fire or incomplete portal blocks before relighting.