From 89c63d222bc71efd9d1396183a54cdb979af5f54 Mon Sep 17 00:00:00 2001
From: Rafal Chlodnicki <rchl2k@gmail.com>
Date: Sat, 26 Sep 2026 18:01:03 +0200
Subject: [PATCH 1/2] Run native ST build on arm64 host when using docker

---
 docker/README.md             | 14 +++++++++-----
 docker/entrypoint.sh         | 32 ++++++++++++++++++++++++++++++++
 docker/ut-run-tests          |  3 ++-
 sbin/install_sublime_text.sh |  9 ++++++---
 4 files changed, 49 insertions(+), 9 deletions(-)
 mode change 100644 => 100755 docker/ut-run-tests

diff --git a/docker/README.md b/docker/README.md
index c55e549b..c623c7ed 100644
--- a/docker/README.md
+++ b/docker/README.md
@@ -123,9 +123,13 @@ ut-run-tests . --color always
 ## Run a single test file
 
 ```sh
-docker run --rm -it \
-  -e PACKAGE=$PACKAGE \
-  -v $PWD:/project \
-  -v unittesting-home:/root \
-  unittesting-local run_tests --tests-dir tests --pattern test_example.py
+ut-run-tests . --file tests/test_example.py
 ```
+
+## ARM hosts (Apple Silicon, arm64 Linux)
+
+On an ARM host, the launcher builds and runs a native arm64 image. The
+container installs the arm64 build of Sublime Text 4.
+
+Runs under amd64 emulation (for example `DOCKER_DEFAULT_PLATFORM=linux/amd64`)
+are not supported.
diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index 05dfa2d6..9dabaf2b 100644
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -1,6 +1,7 @@
 #!/bin/bash
 
 echo PACKAGE = $PACKAGE
+echo ARCHITECTURE = $(uname -m)
 
 set -e
 
@@ -84,6 +85,37 @@ write_package_dependency_marker() {
     printf '%s\n' "$dependency_fingerprint" > "$DEPENDENCY_MARKER_DIR/$PACKAGE.sha256"
 }
 
+ensure_sublime_text_arch_matches() {
+    # A cache volume created on a different architecture holds a Sublime Text
+    # binary that cannot run here, and the bootstrap marker skips reinstall.
+    local binary="$HOME/sublime_text/sublime_text"
+    [ -f "$binary" ] || return 0
+
+    local expected
+    case "$(uname -m)" in
+        x86_64) expected=3e ;;
+        aarch64) expected=b7 ;;
+        *) return 0 ;;
+    esac
+
+    # e_machine field of the ELF header (low byte, little-endian).
+    local actual
+    actual=$(od -An -tx1 -j18 -N1 "$binary" | tr -d ' \n')
+    if [ "$actual" != "$expected" ]; then
+        local found
+        case "$actual" in
+            3e) found=x86_64 ;;
+            b7) found=aarch64 ;;
+            *) found="unknown (ELF machine 0x$actual)" ;;
+        esac
+        echo "Error: the cache volume has a Sublime Text build for $found," >&2
+        echo "but this container runs on $(uname -m)." >&2
+        echo "Run ut-run-tests with --refresh-cache, or use a different cache volume." >&2
+        exit 1
+    fi
+}
+
+ensure_sublime_text_arch_matches
 sudo sh -e /etc/init.d/xvfb start
 ensure_git_identity
 ensure_ci_platform_compat
diff --git a/docker/ut-run-tests b/docker/ut-run-tests
old mode 100644
new mode 100755
index 6a857f7f..eb467e75
--- a/docker/ut-run-tests
+++ b/docker/ut-run-tests
@@ -2,4 +2,5 @@
 set -euo pipefail
 
 SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
-exec python "$SCRIPT_DIR/run_tests.py" "$@"
+PYTHON="$(command -v python3 || command -v python)"
+exec "$PYTHON" "$SCRIPT_DIR/run_tests.py" "$@"
diff --git a/sbin/install_sublime_text.sh b/sbin/install_sublime_text.sh
index 604786b1..5341a718 100644
--- a/sbin/install_sublime_text.sh
+++ b/sbin/install_sublime_text.sh
@@ -28,10 +28,13 @@ if [ -z $SUBLIME_TEXT_VERSION ]; then
 fi
 
 if [ -z $SUBLIME_TEXT_ARCH ]; then
-    SUBLIME_TEXT_ARCH=x64
+    case "$(uname -m)" in
+        aarch64|arm64) SUBLIME_TEXT_ARCH=arm64 ;;
+        *) SUBLIME_TEXT_ARCH=x64 ;;
+    esac
 fi
 
-if [ $SUBLIME_TEXT_VERSION -ge 4 ] && [ "$SUBLIME_TEXT_ARCH" != "x64" ]; then
+if [ $SUBLIME_TEXT_VERSION -ge 4 ] && [ "$SUBLIME_TEXT_ARCH" != "x64" ] && [ "$SUBLIME_TEXT_ARCH" != "arm64" ]; then
     echo "wrong value of $SUBLIME_TEXT_ARCH for Sublime Text version $SUBLIME_TEXT_VERSION"
     exit 1
 fi
@@ -132,7 +135,7 @@ else
         echo "installing sublime text $SUBLIME_TEXT_VERSION"
         for i in {1..20}; do
             if [ $SUBLIME_TEXT_VERSION -ge 4 ]; then
-                URL=$(curl -s "$STWEB" | sed -n 's/.*href="\([^"]*_x64\.tar\.xz\)".*/\1/p')
+                URL=$(curl -s "$STWEB" | sed -n "s/.*href=\"\([^\"]*_${SUBLIME_TEXT_ARCH}\.tar\.xz\)\".*/\1/p")
             else
                 if [ "$SUBLIME_TEXT_ARCH" = "x64" ]; then
                     URL=$(curl -s "$STWEB" | sed -n 's/.*href="\([^"]*x64\.tar\.bz2\)".*/\1/p')

From aad45584646a3fa350b0d58872ceddab38511e19 Mon Sep 17 00:00:00 2001
From: Rafal Chlodnicki <rchl2k@gmail.com>
Date: Sat, 26 Sep 2026 18:58:08 +0200
Subject: [PATCH 2/2] revert manual testing docs

---
 docker/README.md | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/docker/README.md b/docker/README.md
index 7513becf..733d930b 100644
--- a/docker/README.md
+++ b/docker/README.md
@@ -148,7 +148,11 @@ docker run --rm -it \
 Run a single test file
 
 ```sh
-ut-run-tests . --file tests/test_example.py
+docker run --rm -it \
+  -e PACKAGE=$PACKAGE \
+  -v $PWD:/project \
+  -v unittesting-home:/root \
+  unittesting-local run_tests --tests-dir tests --pattern test_example.py
 ```
 
 ## ARM hosts (Apple Silicon, arm64 Linux)