test(get-magento-version): document and pin what happens in various kinds of installs

get-magento-version/get-magento-version.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+WORKING_DIR="${1:-.}"
+PATTERN="magento/product-(community|enterprise)-edition|mage-os/product-community-edition"
+
+cd "$WORKING_DIR"
+
+if [ -f composer.lock ]; then
+  RESULT=$(jq -r --arg p "$PATTERN" '.packages[] | select(.name | test($p)) | "\(.name) \(.version)"' composer.lock | head -1)
+elif [ -f composer.json ]; then
+  RESULT=$(jq -r --arg p "$PATTERN" '.require | to_entries[] | select(.key | test($p)) | "\(.key) \(.value)"' composer.json | head -1)
+fi
+
+PRODUCT=$(echo "${RESULT:-}" | awk '{print $1}')
+VERSION=$(echo "${RESULT:-}" | awk '{print $2}' | sed 's/^v//')
+PROJECT=$(echo "$PRODUCT" | sed 's/product-/project-/')
+
+echo "version=\"$VERSION\""
+echo "project=$PROJECT"