CI: run 4 MC versions per job to halve runner pressure (#3870)

* Run 2 MC versions per CI job to halve runner pressure

Pair up tested versions so each CI job runs 2 versions in parallel.
Reduces matrix from 27 jobs to 14, cutting runner queueing time
while keeping the same wall time per job (~5 min for 2 versions).

Each version's output goes to a separate log file, printed
sequentially with clear headers at the end for easy debugging.
Job names show both versions (e.g. "MC 1.8.8 1.9.4").

Tested locally: 1.9.4 + 1.12.2 both pass (45/45 each) in 5 min
total wall time vs 9 min sequential.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix internal test port conflict when running versions in parallel

Use getPort() instead of hardcoded port 25567 in internalTest.js.
When 2 versions run in the same CI job, both would try to bind
the same port, causing EADDRINUSE.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Fix lint, sync to master, run 4 versions per CI job

- Fix indentation lint errors in internalTest.js
- Group 4 MC versions per CI job (27 versions → 7 jobs)
- Rebased on latest master

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: rom1504 <rom1504@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rom1504

.github/workflows/ci.yml

@@ -32,15 +32,21 @@ jobs:
     - id: set-matrix
       run: |
         node -e "
-          const testedVersions = require('./lib/version').testedVersions;
-          console.log('matrix='+JSON.stringify({'include': testedVersions.map(mcVersion => ({mcVersion}))}))
+          const v = require('./lib/version').testedVersions;
+          const groups = [];
+          const SIZE = 4;
+          for (let i = 0; i < v.length; i += SIZE) {
+            groups.push({ versions: v.slice(i, i + SIZE).join(' ') });
+          }
+          console.log('matrix='+JSON.stringify({'include': groups}))
         " >> $GITHUB_OUTPUT
 
   MinecraftServer:
     needs: PrepareSupportedVersions
     runs-on: ubuntu-latest
+    name: MC ${{ matrix.versions }}
     strategy:
-      matrix: ${{fromJson(needs.PrepareSupportedVersions.outputs.matrix)}}
+      matrix: ${{ fromJson(needs.PrepareSupportedVersions.outputs.matrix) }}
       fail-fast: false
 
     steps:
@@ -58,4 +64,22 @@ jobs:
         run: npm install
 
       - name: Start Tests
-        run: npm run mocha_test -- --retries 2 -g ${{ matrix.mcVersion }}v
+        run: |
+          exit_code=0
+          pids=""
+          for v in ${{ matrix.versions }}; do
+            npm run mocha_test -- --retries 2 -g "${v}v" > "test-${v}.log" 2>&1 &
+            pids="$pids $!"
+          done
+          for pid in $pids; do
+            wait $pid || exit_code=$?
+          done
+          # Print logs sequentially with clear headers
+          for v in ${{ matrix.versions }}; do
+            echo ""
+            echo "=========================================="
+            echo "  Results for Minecraft ${v}"
+            echo "=========================================="
+            cat "test-${v}.log"
+          done
+          exit $exit_code

test/internalTest.js

@@ -7,6 +7,7 @@ const assert = require('assert')
 const { sleep } = require('../lib/promise_utils')
 const nbt = require('prismarine-nbt')
 const { once } = require('../lib/promise_utils')
+const { getPort } = require('./common/util')
 
 for (const supportedVersion of mineflayer.testedVersions) {
   const registry = require('prismarine-registry')(supportedVersion)
@@ -52,54 +53,53 @@ for (const supportedVersion of mineflayer.testedVersions) {
     this.timeout(10 * 1000)
     let bot
     let server
-    beforeEach((done) => {
+    let PORT
+    beforeEach(async function () {
+      PORT = await getPort()
       server = mc.createServer({
         'online-mode': false,
         version: supportedVersion,
-        // 25565 - local server, 25566 - proxy server
-        port: 25567
+        port: PORT
       })
-      server.on('listening', () => {
-        bot = mineflayer.createBot({
-          username: 'player',
-          version: supportedVersion,
-          port: 25567
-        })
-        bot.test = {}
+      await once(server, 'listening')
+      bot = mineflayer.createBot({
+        username: 'player',
+        version: supportedVersion,
+        port: PORT
+      })
+      bot.test = {}
 
-        bot.test.buildChunk = () => {
-          if (bot.supportFeature('tallWorld')) {
-            return new Chunk({ minY: -64, worldHeight: 384 })
-          } else {
-            return new Chunk()
-          }
+      bot.test.buildChunk = () => {
+        if (bot.supportFeature('tallWorld')) {
+          return new Chunk({ minY: -64, worldHeight: 384 })
+        } else {
+          return new Chunk()
         }
+      }
 
-        bot.test.generateLoginPacket = () => {
-          let loginPacket
-          if (bot.supportFeature('usesLoginPacket')) {
-            loginPacket = registry.loginPacket
-            loginPacket.entityId = 0 // Default login packet in minecraft-data 1.16.5 is 1, so set it to 0
-          } else {
-            loginPacket = {
-              entityId: 0,
-              levelType: 'fogetaboutit',
-              gameMode: 0,
-              previousGameMode: 255,
-              worldNames: ['minecraft:overworld'],
-              dimension: 0,
-              worldName: 'minecraft:overworld',
-              hashedSeed: [0, 0],
-              difficulty: 0,
-              maxPlayers: 20,
-              reducedDebugInfo: 1,
-              enableRespawnScreen: true
-            }
+      bot.test.generateLoginPacket = () => {
+        let loginPacket
+        if (bot.supportFeature('usesLoginPacket')) {
+          loginPacket = registry.loginPacket
+          loginPacket.entityId = 0 // Default login packet in minecraft-data 1.16.5 is 1, so set it to 0
+        } else {
+          loginPacket = {
+            entityId: 0,
+            levelType: 'fogetaboutit',
+            gameMode: 0,
+            previousGameMode: 255,
+            worldNames: ['minecraft:overworld'],
+            dimension: 0,
+            worldName: 'minecraft:overworld',
+            hashedSeed: [0, 0],
+            difficulty: 0,
+            maxPlayers: 20,
+            reducedDebugInfo: 1,
+            enableRespawnScreen: true
           }
-          return loginPacket
         }
-        done()
-      })
+        return loginPacket
+      }
     })
     afterEach((done) => {
       bot.on('end', () => {