Use GitHub Releases API to resolve Linux package asset URLs

The PowerShell release naming convention changed over time (e.g.
powershell-preview_ vs powershell_ prefix for .deb packages).
Instead of hardcoding the package filename pattern, query the
GitHub Releases API for the actual asset URLs. This handles all
historical and future naming conventions correctly.

Author: MariusStorhaug

action.yml

@@ -96,24 +96,44 @@ runs:
         # Determine Linux distribution type
         ARCH=$(dpkg --print-architecture 2>/dev/null || rpm --eval '%{_arch}' 2>/dev/null || echo "x86_64")
 
+        # Query GitHub Releases API for the actual asset URLs to handle naming
+        # convention differences across releases (e.g. powershell-preview_ vs powershell_).
+        RELEASE_JSON=$(
+          curl -s -f \
+            -H "Accept: application/vnd.github+json" \
+            -H "Authorization: Bearer $GITHUB_TOKEN" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            "https://api.github.com/repos/PowerShell/PowerShell/releases/tags/v${REQUESTED_VERSION}"
+        )
+        if [[ -z "$RELEASE_JSON" ]]; then
+          echo "Error: Failed to fetch release info for v${REQUESTED_VERSION} from GitHub."
+          exit 1
+        fi
+
         if command -v apt-get >/dev/null || command -v dpkg >/dev/null; then
           # Debian/Ubuntu based
           echo "Detected Debian/Ubuntu based system..."
-          DEB_NAME="powershell_${REQUESTED_VERSION}-1.deb_${ARCH}.deb"
-          URL="https://github.com/PowerShell/PowerShell/releases/download/v${REQUESTED_VERSION}/${DEB_NAME}"
+          URL=$(echo "$RELEASE_JSON" | jq -r --arg arch "$ARCH" \
+            '[.assets[] | select(.name | test("^powershell.*\\.deb_" + $arch + "\\.deb$"))] | .[0].browser_download_url // empty')
+          if [[ -z "$URL" ]]; then
+            echo "Error: No .deb package found for architecture '$ARCH' in release v${REQUESTED_VERSION}."
+            exit 1
+          fi
+          DEB_NAME=$(basename "$URL")
           echo "Downloading from: $URL"
           wget -q "$URL" -O "$DEB_NAME"
           echo "Starting installation of PowerShell [$REQUESTED_VERSION]..."
           sudo dpkg -i "$DEB_NAME" || sudo apt-get -f install -y
         elif command -v rpm >/dev/null; then
           # RHEL/Fedora/CentOS based
           echo "Detected RHEL/Fedora/CentOS based system..."
-          if [[ "$ARCH" == "aarch64" ]]; then
-            RPM_NAME="powershell-${REQUESTED_VERSION}-1.rh.${ARCH}.rpm"
-          else
-            RPM_NAME="powershell-${REQUESTED_VERSION}-1.rh.x86_64.rpm"
+          URL=$(echo "$RELEASE_JSON" | jq -r --arg arch "$ARCH" \
+            '[.assets[] | select(.name | test("^powershell.*\\.rh\\." + (if $arch == "aarch64" then $arch else "x86_64" end) + "\\.rpm$"))] | .[0].browser_download_url // empty')
+          if [[ -z "$URL" ]]; then
+            echo "Error: No .rpm package found for architecture '$ARCH' in release v${REQUESTED_VERSION}."
+            exit 1
           fi
-          URL="https://github.com/PowerShell/PowerShell/releases/download/v${REQUESTED_VERSION}/${RPM_NAME}"
+          RPM_NAME=$(basename "$URL")
           echo "Downloading from: $URL"
           wget -q "$URL" -O "$RPM_NAME"
           echo "Starting installation of PowerShell [$REQUESTED_VERSION]..."