autotester: use upstream HeadlessMC 2.10.0

Author: Skidamek

autotester/README.md

@@ -87,18 +87,14 @@ The client image builds its HeadlessMC launcher from the git repo and ref in
 
 ```yaml
 headlessmc:
-  repo: "https://github.com/Skidamek/headlessmc.git"
-  ref: "64d3c126e72bbfccf95e71afaa6536f50bc64097"  # branch, tag, or commit SHA
+  repo: "https://github.com/headlesshq/headlessmc.git"
+  ref: "2.10.0"  # branch, tag, or commit SHA
 ```
 
-`ref` may be a branch, tag, or commit SHA; it is pinned to a SHA here for
-reproducible image builds. This default ref carries the patch required to launch
-**MC 26.2** headlessly
-(stock HeadlessMC can't yet — its LWJGL stubs don't satisfy 26.2's new render
-backend); it does not change behavior on other versions. Point `repo`/`ref` at
-any other HeadlessMC build and rebuild the image
-(`uv --project autotester run autotester build-images`). If they are unset, the
-build falls back to upstream HeadlessMC (`headlesshq/headlessmc`).
+`ref` may be a branch, tag, or commit SHA; the default uses the immutable
+upstream 2.10.0 release for reproducible image builds and Minecraft 26.2
+support. Point `repo`/`ref` at another HeadlessMC build and rebuild the image
+with `uv --project autotester run autotester build-images`.
 
 ## Scenarios
 

autotester/docker/client/Dockerfile

@@ -1,10 +1,8 @@
 # Git repository and ref the HeadlessMC launcher is built from. These are
 # normally supplied by `autotester build-images` from settings.yaml
-# (headlessmc.repo/ref). The defaults below are only a fallback for a bare
-# `docker build` and point at upstream HeadlessMC; set headlessmc.repo/ref in
-# settings.yaml to build a patched launcher (e.g. for MC 26.2 headless).
+# (headlessmc.repo/ref). The defaults also use the pinned upstream release.
 ARG HEADLESSMC_REPO=https://github.com/headlesshq/headlessmc.git
-ARG HEADLESSMC_REF=main
+ARG HEADLESSMC_REF=2.10.0
 
 # ── Builder: compile the HeadlessMC launcher wrapper jar ──────────────
 # HeadlessMC must be built with JDK 21 (its Gradle build rejects newer JDKs).
@@ -35,37 +33,18 @@ FROM ubuntu:26.04
 ENV DEBIAN_FRONTEND=noninteractive
 ENV HMC_HOME=/work/hmc-cache
 
-# Install Java 17, 21, 25 from repos. Two things newer FancyModLoader (21.10+/26.x) needs that
-# the previous headless-only setup didn't provide:
-#  - The full (non-headless) *-jre packages: FatalErrorReporting.reportFatalError tries a Swing
-#    dialog even in headless mode - if it can't (java.desktop's libawt_xawt.so is only shipped
-#    by the non-headless package), that UnsatisfiedLinkError itself crashes the client and
-#    replaces the real error in the log, making any such failure undiagnosable.
-#  - xvfb (below): even with -Djava.awt.headless=true, this JDK's HeadlessGraphicsEnvironment
-#    still wraps a real X11GraphicsEnvironment internally on Linux and fails without a display
-#    to connect to - so Swing dialogs need a (virtual) X server regardless of the headless flag.
+# HeadlessMC's LWJGL transformer does not need an X server or desktop Java runtime.
 RUN apt-get update \
     && apt-get install -y --no-install-recommends \
         ca-certificates \
         curl \
         unzip \
         bash \
         procps \
-        xvfb \
         libatomic1 \
-        libx11-6 \
-        libxext6 \
-        libxrender1 \
-        libxtst6 \
-        libxi6 \
-        libxrandr2 \
-        libxxf86vm1 \
-        libgl1 \
-        libglx-mesa0 \
-        libasound2t64 \
-        openjdk-17-jre \
-        openjdk-21-jre \
-        openjdk-25-jre \
+        openjdk-17-jre-headless \
+        openjdk-21-jre-headless \
+        openjdk-25-jre-headless \
     && rm -rf /var/lib/apt/lists/*
 
 RUN mkdir -p /opt/headlessmc /opt/automodpack /work/game /work/hmc-cache \

autotester/docker/client/run-headlessmc-client

@@ -124,8 +124,5 @@ timeout 20 hmc --command "download ${minecraft}" 2>/dev/null || true
 hmc --command "config -refresh" 2>/dev/null || true
 
 # ── Launch ─────────────────────────────────────────────────────────
-# xvfb-run: newer FancyModLoader's fatal-error Swing dialog needs a real X display even with
-# -Djava.awt.headless=true (see Dockerfile) - give it a virtual one so a genuine fatal error
-# reports its real cause instead of crashing on top of it with an unrelated X11/AWT error.
-exec timeout "$client_timeout" xvfb-run -a hmc \
+exec timeout "$client_timeout" hmc \
   --command "launch ${launch_target} -lwjgl -offline --jvm \"${jvmargs}\" ${gameargs}"

autotester/settings.yaml

@@ -36,14 +36,10 @@ serverTypes:
   neoforge: NEOFORGE
 
 headlessmc:
-  # Git repository and ref the HeadlessMC launcher is built from. The default
-  # builds the patch required to launch MC 26.2 headlessly; point these at a
-  # different repo/ref to use another HeadlessMC build. ref may be a branch, tag
-  # or commit SHA — pinned to a SHA here for reproducible builds (this is the
-  # head of the mc26.2-headless branch; bump it when the fork moves, or switch
-  # to the upstream tag once the patch is merged upstream).
-  repo: "https://github.com/Skidamek/headlessmc.git"
-  ref: "64d3c126e72bbfccf95e71afaa6536f50bc64097"
+  # Git repository and ref the HeadlessMC launcher is built from. ref may be a
+  # branch, tag, or commit SHA; pin the upstream release for reproducible builds.
+  repo: "https://github.com/headlesshq/headlessmc.git"
+  ref: "2.10.0"
 
 timeouts:
   serverStartSeconds: 180