SchematicConversionLog

Collapses the per-block "Unsupported key" spam Minecraft's data converter produces while reading schematics saved by older versions.

Shipped .schem files carry the Minecraft DataVersion they were saved at, so WorldEdit runs every block entity in them through Mojang's DataFixerUpper. Entries whose type no longer exists in the running version — minecraft:bed is the common one, block entities for beds went away in 1.13 when bed colour moved into the block state — come back as a failed DataResult, which the server logs at ERROR, once per occurrence. A full content install produces 424 identical lines per load.

Nothing is wrong: the entry carried no information the current format needs, the block itself converts fine, and the structure pastes correctly. Reported as hundreds of ERROR lines it reads like a broken install, so it is counted instead and reported as a single line naming the distinct keys involved.

This is third-party output, so the only place to intervene is the logging backend. The filter is installed for the duration of a load on the logger configuration that serves DataFixerUpper — the nearest ancestor config, which is ROOT on stock servers — and removed afterwards, so it verifies the event's exact logger name before denying anything. Everything is guarded: a server whose logging backend is not log4j-core keeps its original output rather than failing to load schematics.