devcontainer: handle hosts without X11 (#29537)

* Setup xauthority link on host in initializeCommand

* Create a dummy xauthority if it does no exist on host machine

* Remove xauthority line from ci test

.devcontainer/.gitignore

@@ -0,0 +1 @@
+.Xauthority

.devcontainer/devcontainer.json

@@ -5,6 +5,7 @@
   },
   "postCreateCommand": "bash -c 'if [[ $DISPLAY == *xquartz* ]]; then echo \"export DISPLAY=host.docker.internal:0\" >> /root/.bashrc; fi'",
   "postStartCommand": "git config --file .gitmodules --get-regexp path | awk '{ print $2 }' | xargs -I{} git config --global --add safe.directory \"$PWD/{}\"",
+  "initializeCommand": ".devcontainer/setup_host.sh",
   "privileged": true,
   "containerEnv": {
     "DISPLAY": "${localEnv:DISPLAY}",
@@ -13,7 +14,7 @@
   },
   "runArgs": [
     "--volume=/tmp/.X11-unix:/tmp/.X11-unix",
-    "--volume=${localEnv:XAUTHORITY}:/root/.Xauthority",
+    "--volume=${localWorkspaceFolder}/.devcontainer/.Xauthority:/root/.Xauthority",
     "--volume=${localEnv:HOME}/.comma:/root/.comma",
     "--volume=/tmp/comma_download_cache:/tmp/comma_download_cache",
     "--volume=/tmp/devcontainer_scons_cache:/tmp/scons_cache",

.devcontainer/setup_host.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+# setup links to Xauthority
+XAUTHORITY_LINK=".devcontainer/.Xauthority"
+rm -f $XAUTHORITY_LINK
+if [[ -z $XAUTHORITY ]]; then
+    echo "XAUTHORITY not set. Fallback to ~/.Xauthority ..."
+    if ! [[ -f $HOME/.Xauthority ]]; then
+        echo "~/.XAuthority file does not exist. GUI tools may not work properly."
+        touch $XAUTHORITY_LINK # dummy file to satisfy container volume mount
+    else
+        ln -sf $HOME/.Xauthority $XAUTHORITY_LINK
+    fi
+else
+    ln -sf $XAUTHORITY $XAUTHORITY_LINK
+fi

.github/workflows/tools_tests.yaml

@@ -105,8 +105,6 @@ jobs:
     - name: Build dev container image
       run: devcontainer build --workspace-folder .
     - name: Run dev container
-      run: |
-        export XAUTHORITY="$HOME/.Xauthority"
-        devcontainer up --workspace-folder .
+      run: devcontainer up --workspace-folder .
     - name: Test environment
       run: devcontainer exec --workspace-folder . scons --dry-run