Add workflow to autogen mappings

.github/workflows/main.yml

@@ -0,0 +1,66 @@
+name: Check for new Minecraft snapshot
+
+on:
+  schedule:
+    - cron: '10 * * * *'
+  workflow_dispatch:
+
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Setup Python
+        uses: actions/setup-python@v4
+
+      - name: Setup Java JDK
+        uses: actions/setup-java@v3
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: Setup Maven
+        uses: s4u/setup-maven-action@v1.7.0
+        with:
+          java-version: 17
+
+      - name: Configure Git details
+        run: |
+          git config --global user.name 'not quite kenny'
+          git config --global user.email 'notactuallykennytv2@something.com'
+
+      - name: Check for snapshot
+        run: pip install -r requirements.txt && python download_server.py
+
+      # Wooyeah
+      - name: Read last snapshot
+        id: last_snapshot
+        uses: juliangruber/read-file-action@v1
+        with:
+          path: ./last_snapshot.txt
+      - name: Read last release
+        id: last_release
+        uses: juliangruber/read-file-action@v1
+        with:
+          path: ./last_release.txt
+      - name: Read next release
+        id: next_release
+        uses: juliangruber/read-file-action@v1
+        with:
+          path: ./next_release.txt
+
+      - name: Compile MappingsGenerator jar
+        run: mvn package && mvn package && mv target/MappingsGenerator-*.jar ./MappingsGenerator.jar
+      - name: Run MappingsGenerator
+        run: java -jar MappingsGenerator.jar server.jar ${{ steps.next_release.outputs.content }} ${{ steps.last_release.outputs.content }}
+      - name: Pack mappings
+        run: java -cp MappingsGenerator.jar com.viaversion.mappingsgenerator.MappingsOptimizer ${{ steps.last_release.outputs.content }} ${{ steps.next_release.outputs.content }}
+      - name: Pack backwards mappings
+        run: java -cp MappingsGenerator.jar com.viaversion.mappingsgenerator.MappingsOptimizer ${{ steps.next_release.outputs.content }} ${{ steps.last_release.outputs.content }}
+
+      - name: Commit changes
+        run: |
+          git add .
+          git commit -m "${{ steps.last_snapshot.outputs.content }}"
+          git push

.gitignore

@@ -1,3 +1,6 @@
+libraries/
+generated/
+
 ### Java files ###
 *.class
 

README.md

@@ -35,7 +35,7 @@ If you want to generate the compact mapping files with already present json file
 its own by starting the `MappingsOptimizer` class with the two arguments flipped:
 
 ```
-java -DbundlerMainClass=com.viaversion.mappinggenerator.MappingsOptimizer -jar <from version> <to version>
+java -cp MappingsGenerator.jar com.viaversion.mappingsgenerator.MappingsOptimizer <from version> <to version>
 ```
 
 ## Json format
@@ -92,7 +92,8 @@ mapped ids in a simple int→int mapping over the two arrays.
 ### Shifted value storage
 
 The shifted value storage stores two int arrays: One containing the unmapped ids that end a sequence of mapped ids. For
-an index `i`, all unmapped ids between `at[i] + sequence` (inclusive) and `at[i + 1]` (exclusive) are mapped to `to[i] + sequence`.
+an index `i`, all unmapped ids between `at[i] + sequence` (inclusive) and `at[i + 1]` (exclusive) are mapped
+to `to[i] + sequence`.
 
 * `id` (byte tag) is `2`
 * `at` (int array tag) contains the unmapped ids, where their mapped is is *not* simply the last mapped id + 1
@@ -107,5 +108,5 @@ simply leaving out the entry to make sure ids stay in bounds.
 
 ## License
 
-The Java code is licensed under the GNU GPL v3 license. The files under `mappings/` are free to copy, use, and expand
-upon in whatever way you like.
+The Java and Python code is licensed under the GNU GPL v3 license. The files under `mappings/` are free to copy, use,
+and expand upon in whatever way you like.

download_server.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+import json
+import os
+import six
+import subprocess
+import sys
+import wget
+from pathlib import Path
+from urllib.error import HTTPError
+
+MANIFEST_LOCATION = "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json"
+
+
+def load_json(url):
+    try:
+        with six.moves.urllib.request.urlopen(url) as stream:
+            return json.load(stream)
+    except HTTPError as e:
+        print('HTTP Error')
+        print(e)
+        sys.exit(-1)
+
+
+def main():
+    # Get latest version from manifest
+    manifest = load_json(MANIFEST_LOCATION)
+    latest = manifest["latest"]
+    snapshot = latest["snapshot"]
+    release = latest["release"]
+
+    # Compare with old version
+    last_release = release
+    last_snapshot_path = Path('last_snapshot.txt')
+    if last_snapshot_path.exists():
+        with open(last_snapshot_path, 'r') as f:
+            if f.readline() == snapshot:
+                sys.exit(1)
+
+    # Download version data
+    manifestEntry = None
+    for entry in manifest["versions"]:
+        if entry["id"] == snapshot:
+            manifestEntry = entry
+            break
+
+    if manifestEntry is None:
+        print("VERSION DATA FOR", snapshot, "NOT FOUND")
+        sys.exit(1)
+
+    # Rename old server jar as backup and download new one
+    if os.path.exists("server_old.jar"):
+        os.remove("server_old.jar")
+    if os.path.exists("server.jar"):
+        os.rename('server.jar', 'server_old.jar')
+
+    print("=== Downloading server...")
+    versionData = load_json(manifestEntry["url"])
+    serverUrl = versionData["downloads"]["server"]["url"]
+    wget.download(serverUrl, "server.jar")
+
+    with open(last_snapshot_path, 'w') as f:
+        f.write(snapshot)
+    with open(Path('last_release.txt'), 'w') as f:
+        f.write(release)
+
+    sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()

last_release.txt

@@ -0,0 +1 @@
+1.19.3

last_snapshot.txt

@@ -0,0 +1 @@
+1.19.4-pre2

next_release.txt

@@ -0,0 +1 @@
+1.19.4

pom.xml

@@ -7,7 +7,7 @@
     <groupId>com.viaversion</groupId>
     <artifactId>mappingsgenerator</artifactId>
     <name>MappingsGenerator</name>
-    <version>3.0.0</version>
+    <version>3.0.1</version>
 
     <url>https://github.com/ViaVersion/Mappings</url>
     <inceptionYear>2020</inceptionYear>

requirements.txt

@@ -0,0 +1,2 @@
+six==1.16.0
+wget==3.2

src/main/java/com/viaversion/mappingsgenerator/MappingsOptimizer.java

@@ -66,13 +66,12 @@ public final class MappingsOptimizer {
     private static final String OUTPUT_FILE_FORMAT = "mappings-%sto%s.nbt";
     private static final String OUTPUT_IDENTIFIERS_FILE_FORMAT = "identifiers-%s.nbt";
     private static final Set<String> SAVED_IDENTIFIER_FILES = new HashSet<>();
-    private static final boolean RUN_ALL = true;
 
     public static void main(final String[] args) throws IOException {
         MAPPINGS_DIR.mkdirs();
         OUTPUT_DIR.mkdirs();
 
-        if (RUN_ALL) {
+        if (false) {
             runAll();
             return;
         }