chore(common): allow build agents to automatically select emsdk version

The build agents will now automatically install and activate the
Emscripten version found in minimum-versions.inc.sh when configuring
WASM projects. For developer machines, this behaviour can be enabled by
setting the environment variable `KEYMAN_USE_EMSDK` (recommended).

This will be back-ported to 17.0 so that we can ensure that all builds
use a consistent Emscripten version.

resources/build/minimum-versions.inc.sh

@@ -20,8 +20,7 @@ KEYMAN_MIN_TARGET_VERSION_CHROME=95.0         # Final version that runs on Andro
 # Dependency versions
 KEYMAN_MIN_VERSION_NODE_MAJOR=20              # node version source of truth is /package.json:/engines/node
 KEYMAN_MIN_VERSION_NPM=10.5.1                 # 10.5.0 has bug, discussed in #10350
-KEYMAN_MIN_VERSION_EMSCRIPTEN=3.1.44          # Warning: 3.1.45 is bad (#9529); newer versions work
-KEYMAN_MAX_VERSION_EMSCRIPTEN=3.1.58          # See #9529
+KEYMAN_MIN_VERSION_EMSCRIPTEN=3.1.58          # Use KEYMAN_USE_EMSDK to automatically update to this version
 KEYMAN_MIN_VERSION_VISUAL_STUDIO=2019
 KEYMAN_MIN_VERSION_MESON=1.0.0
 

resources/locate_emscripten.inc.sh

@@ -1,6 +1,8 @@
 # shellcheck shell=bash
 # no hashbang for .inc.sh
 
+. "$KEYMAN_ROOT/resources/build/minimum-versions.inc.sh"
+
 #
 # We don't want to rely on emcc being on the path, because Emscripten puts far
 # too many things onto the path (in particular for us, node).
@@ -34,4 +36,38 @@ locate_emscripten() {
   fi
   [[ -f ${EMSCRIPTEN_BASE}/${EMCC_EXECUTABLE} && ! -x ${EMSCRIPTEN_BASE}/${EMCC_EXECUTABLE} ]] && builder_die "locate_emscripten: Variable EMSCRIPTEN_BASE ($EMSCRIPTEN_BASE) contains ${EMCC_EXECUTABLE} but it is not executable"
   [[ -x ${EMSCRIPTEN_BASE}/${EMCC_EXECUTABLE} ]] || builder_die "locate_emscripten: Variable EMSCRIPTEN_BASE ($EMSCRIPTEN_BASE) does not point to ${EMCC_EXECUTABLE}'s folder"
+
+  verify_emscripten_version
+}
+
+# Ensure that we use correct version of emsdk on build agents.
+# For developers, define KEYMAN_USE_SDK to do this on your
+# build machine.
+verify_emscripten_version() {
+  if [[ "$VERSION_ENVIRONMENT" != local || ! -z "${KEYMAN_USE_EMSDK+x}" ]]; then
+    _select_emscripten_version_with_emsdk
+  fi
+}
+
+# Use emsdk to select the appropriate version of Emscripten
+# according to minimum-versions.inc.sh
+_select_emscripten_version_with_emsdk() {
+  if [[ -z "${EMSCRIPTEN_BASE+x}" ]]; then
+    builder_die "Variable EMSCRIPTEN_BASE must be set"
+  fi
+
+  if [[ -z "${KEYMAN_MIN_VERSION_EMSCRIPTEN+x}" ]]; then
+    builder_die "Variable KEYMAN_MIN_VERSION_EMSCRIPTEN must be set"
+  fi
+
+  pushd "${EMSCRIPTEN_BASE}/../.." > /dev/null
+  if [[ ! -f emsdk ]]; then
+    builder_die "emsdk[.bat] should be in $(pwd)"
+  fi
+
+  export EMSDK_KEEP_DOWNLOADS=1
+  git pull
+  ./emsdk install "$KEYMAN_MIN_VERSION_EMSCRIPTEN"
+  ./emsdk activate "$KEYMAN_MIN_VERSION_EMSCRIPTEN"
+  popd > /dev/null
 }