Minecraft-Console-Client/tools

MCC Version Adaptation Tools

Scripts for analyzing Minecraft version differences and generating MCC palette files.

Requires: Python 3.10+

Data Sources

Two types of data can be used as input:

Source	How to Get	Authoritative?
Decompiled Java source	MinecraftDecompiler.jar → MinecraftOfficial/<ver>-decompiled/	Mostly (see caveat below)
Server data reports	java -DbundlerMainClass=net.minecraft.data.Main -jar server.jar --reports	Yes

Important since MC 1.21.9: Some items and blocks are registered outside Items.java/Blocks.java field declarations (via block registration callbacks). In these cases, the decompiled source undercounts entries. Always use server data reports for item and block palettes when available.

Decompiling a new MC version

# Server side (default) — also downloads server.jar into MinecraftOfficial/downloads/<ver>/
tools/decompile.sh --version 1.21.9

# Client side
tools/decompile.sh --version 1.21.9 --side CLIENT

If you keep server assets outside the repo, set MCC_SERVERS=/path/to/servers before using tools/mcc-env.sh or tools/start-server.sh.

The script auto-downloads MinecraftDecompiler.jar from GitHub releases if it doesn't exist.

Generating server data reports

cd /tmp
java -DbundlerMainClass=net.minecraft.data.Main \
  -jar $MCC_SERVERS/<version>/server.jar \
  --reports --output /tmp/mc_reports

This generates:

• /tmp/mc_reports/reports/registries.json — all registries with protocol IDs
• /tmp/mc_reports/reports/blocks.json — all blocks with block state IDs
• /tmp/mc_reports/reports/packets.json — packet protocol definitions

diff_registries.py — Compare registries between versions

Compares Items, EntityTypes, Blocks, DataComponents, and EntityDataSerializers between two MC versions. Reports whether each palette needs updating, lists added/removed entries, and shows ID shift statistics.

# Basic comparison (decompiled source only)
python3 tools/diff_registries.py 1.21.8 1.21.9

# With cross-validation against server registries.json (recommended)
python3 tools/diff_registries.py 1.21.8 1.21.9 --registry /tmp/mc_reports/reports/registries.json

The --registry flag enables cross-validation: compares the count and set of entries found in decompiled Java source against the server's authoritative registry. Any mismatches indicate that palette generation must use server data instead of Java source.

Output indicates for each registry:

• IDENTICAL → reuse existing palette
• PALETTE UPDATE NEEDED → create new palette file + update version routing
• Count MISMATCH (with --registry) → server has entries not in Java source

gen_item_palette.py — Generate ItemPalette C# file

Two modes:

# Preferred: from server registries.json (accurate since 1.21.9)
python3 tools/gen_item_palette.py --from-registry /tmp/mc_reports/reports/registries.json 1219

# Legacy: from decompiled Items.java
python3 tools/gen_item_palette.py 1.21.1 121

Output: MinecraftClient/Inventory/ItemPalettes/ItemPalette<suffix>.cs

Validates each item name against ItemType.cs and warns about missing enum values. Add missing values to ItemType.cs in alphabetical order before compiling.

gen_block_palette.py — Generate BlockPalette C# file

python3 tools/gen_block_palette.py /tmp/mc_reports/reports/blocks.json 1219
# → MinecraftClient/Mapping/BlockPalettes/Palette1219.cs

Generates a complete block palette with block state ID ranges from the server's blocks.json. Validates against Material.cs and warns about missing enum values.

gen_entity_palette.py — Generate EntityPalette C# file

python3 tools/gen_entity_palette.py /tmp/mc_reports/reports/registries.json 1219
# → MinecraftClient/Mapping/EntityPalettes/EntityPalette1219.cs

Generates entity type palette from server's registries.json. Validates against EntityType.cs and warns about missing enum values.

gen_entity_metadata_palette.py — Generate EntityMetadataPalette C# file

python3 tools/gen_entity_metadata_palette.py 1.21.9 1219
# → MinecraftClient/Mapping/EntityMetadataPalettes/EntityMetadataPalette1219.cs

Reads EntityDataSerializers.java static block registration order. Maps Java field names to MCC's EntityMetaDataType enum. If a new serializer type appears that isn't in the mapping table, it will warn you to update:

1. The script's FIELD_TO_ENUM dict
2. MCC's EntityMetaDataType.cs enum
3. DataTypes.cs ReadNextMetadata() read logic

gen_command_argument_registry.py — Generate DeclareCommands registry arrays

python3 tools/gen_command_argument_registry.py 1.20.6 1.21.5 1.21.6

Reads ArgumentTypeInfos.java, skips the SharedConstants.IS_RUNNING_IN_IDE block, and prints C# array initializers for the runtime COMMAND_ARGUMENT_TYPE registry order. Use this when Mojang inserts new command argument types and the modern DeclareCommands parser needs updated ID routing.

gen_block_shapes.py — Download & compact block collision shapes

Downloads block collision shapes from PrismarineJS minecraft-data and compacts them into a single JSON for MCC's physics engine.

# Auto-download for a specific MC version
python3 tools/gen_block_shapes.py 26.1
# → MinecraftClient/Physics/BlockShapeData.json

# From a local file (if network is slow)
python3 tools/gen_block_shapes.py --from-file /path/to/blockCollisionShapes.json

Output: MinecraftClient/Physics/BlockShapeData.json (embedded as a resource via .csproj).

Data source: https://raw.githubusercontent.com/PrismarineJS/minecraft-data/master/data/pc/<version>/blockCollisionShapes.json

Uses curl with resume (-C -) for reliable download over slow connections. Falls back to manual download if retries are exhausted.

Recommended workflow

1. Generate server reports (Step 0)
2. Run diff_registries.py --registry to identify changes and validate source completeness
3. For each registry needing update:
   • Items: gen_item_palette.py --from-registry
   • Blocks: gen_block_palette.py
   • Entities: gen_entity_palette.py
   • Metadata: gen_entity_metadata_palette.py
4. Update block collision shapes: gen_block_shapes.py
5. Add any missing enum values to ItemType.cs, Material.cs, EntityType.cs, EntityMetaDataType.cs
6. Update version routing (see SKILL.md)
7. Build and test