Fix hash calculations

cursor-release.nix

@@ -3,7 +3,7 @@
   #
   # Notes:
   # - `sha256` values are Nix base32 hashes (as used by `fetchurl { sha256 = "..."; }`).
-  version = "2.2.44";
+  version = "2.2.43";
 
   sha256 = {
     x86_64-linux = "1bgifjyscqymbz0srw8np9pc88gwcccic3z4cnydyfskxhnyj0sr";

flake.nix

@@ -116,7 +116,12 @@
           pkgs = pkgsFor system;
           version = cursorRelease.version;
           channel = channelForSystem.${system} or (throw "Unsupported system: ${system}");
-          url = "https://api2.cursor.sh/updates/download/golden/${channel}/cursor/${version}";
+          # Prefer the stable resolved downloads.cursor.com URL stored by ./update-cursor.sh.
+          # Fallback to the API URL for older cursor-release.nix files.
+          url =
+            if cursorRelease ? url && cursorRelease.url ? ${system}
+            then cursorRelease.url.${system}
+            else "https://api2.cursor.sh/updates/download/golden/${channel}/cursor/${version}";
           sha256 = cursorRelease.sha256.${system} or "0000000000000000000000000000000000000000000000000000";
         in
         {

update-cursor.sh

@@ -15,10 +15,17 @@ RELEASE_FILE="$SCRIPT_DIR/cursor-release.nix"
 CHANNEL_FOR_SYSTEM_x86_64_linux="linux-x64"
 CHANNEL_FOR_SYSTEM_aarch64_linux="linux-arm64"
 
-# Get a redirect URL for a given "track" pointer (e.g. latest, 2.2).
+# Extract Cursor semver from a resolved download URL (Location header).
+extract_version_from_url() {
+    local url="${1:-}"
+    echo "$url" | grep -Eo 'Cursor-[0-9]+\.[0-9]+\.[0-9]+' | sed 's/Cursor-//' || true
+}
+
+# Get a redirect URL for a given pointer (e.g. latest, 2.2, 2.2.44) and channel.
 get_redirect_url() {
-    local track="${1:?track is required}"
+    local channel="${1:?channel is required}"
-    local url="https://api2.cursor.sh/updates/download/golden/linux-x64/cursor/${track}"
+    local pointer="${2:?pointer is required}"
+    local url="https://api2.cursor.sh/updates/download/golden/${channel}/cursor/${pointer}"
 
     # Avoid stale CDN/proxy cache results for fast-moving pointers like "latest".
     curl -sS -I \
@@ -29,12 +36,58 @@ get_redirect_url() {
       | tr -d '\r\n'
 }
 
-# Resolve a track pointer (e.g. latest, 2.2) into an actual semver (e.g. 2.2.44).
+# Resolve an exact version to a stable downloads.cursor.com URL.
+#
+# Guardrail: Cursor's API has been observed to sometimes redirect an "exact version" URL
+# (e.g. /cursor/2.2.44) to an older AppImage (e.g. 2.2.43). When that happens, we retry via
+# the major.minor pointer (e.g. /cursor/2.2) and only proceed if it resolves to the requested
+# version.
+resolve_download_url_for_version() {
+    local channel="${1:?channel is required}"
+    local version="${2:?version is required}"
+
+    local redirect_url resolved_version
+    redirect_url="$(get_redirect_url "$channel" "$version")"
+    if [[ -z "$redirect_url" ]]; then
+        echo "Error: Could not resolve Location header for ${channel} ${version}" >&2
+        return 1
+    fi
+
+    resolved_version="$(extract_version_from_url "$redirect_url")"
+    if [[ "$resolved_version" == "$version" ]]; then
+        echo "$redirect_url"
+        return 0
+    fi
+
+    local minor_pointer fallback_redirect fallback_resolved
+    minor_pointer="$(get_track_from_version "$version")"
+    echo "Warning: ${channel} ${version} resolved to ${resolved_version:-unknown}; retrying via pointer ${minor_pointer}" >&2
+    fallback_redirect="$(get_redirect_url "$channel" "$minor_pointer")"
+    if [[ -z "$fallback_redirect" ]]; then
+        echo "Error: Could not resolve Location header for fallback ${channel} ${minor_pointer}" >&2
+        return 1
+    fi
+
+    fallback_resolved="$(extract_version_from_url "$fallback_redirect")"
+    if [[ "$fallback_resolved" != "$version" ]]; then
+        echo "Error: Could not resolve requested version $version for channel $channel." >&2
+        echo "Tried:" >&2
+        echo "  - /cursor/${version} -> ${resolved_version:-unknown} ($redirect_url)" >&2
+        echo "  - /cursor/${minor_pointer} -> ${fallback_resolved:-unknown} ($fallback_redirect)" >&2
+        echo "Upstream pointers/caches are inconsistent; try again later." >&2
+        return 1
+    fi
+
+    echo "$fallback_redirect"
+}
+
+# Resolve a pointer (e.g. latest, 2.2) into an actual semver (e.g. 2.2.44).
 get_latest_version() {
     local track="${1:-latest}"
 
     local redirect_url
-    redirect_url="$(get_redirect_url "$track")"
+    # Version discovery can just use linux-x64; the resolved version is shared across architectures.
+    redirect_url="$(get_redirect_url "$CHANNEL_FOR_SYSTEM_x86_64_linux" "$track")"
 
     if [[ -n "$redirect_url" ]]; then
         # Extract version from URL like: .../Cursor-2.2.44-x86_64.AppImage
@@ -75,7 +128,7 @@ semver_max() {
 # Function to compute sha256 for a given system+version
 prefetch_sha256() {
     local system="$1"
-    local version="$2"
+    local url="$2"
     local channel=""
 
     case "$system" in
@@ -84,15 +137,13 @@ prefetch_sha256() {
         *) echo "Error: Unsupported system: $system" >&2; return 1 ;;
     esac
 
-    local url="https://api2.cursor.sh/updates/download/golden/${channel}/cursor/${version}"
-
     if ! command -v nix-prefetch-url >/dev/null 2>&1; then
         echo "Error: nix-prefetch-url not found. Please install Nix (or nix-prefetch-url) and retry." >&2
         return 1
     fi
 
     # IMPORTANT: this function is captured by command substitution. Keep stdout as the hash only.
-    echo "Prefetching ($system) from: $url" >&2
+    echo "Prefetching ($system) from resolved URL: $url" >&2
 
     local out hash
     out="$(nix-prefetch-url --type sha256 "$url" 2>&1)"
@@ -114,9 +165,12 @@ update_release() {
 
     echo "Computing hashes for version: $version"
 
-    local sha_x86 sha_aarch64
+    local url_x86 url_aarch64 sha_x86 sha_aarch64
-    sha_x86="$(prefetch_sha256 x86_64-linux "$version")"
+    url_x86="$(resolve_download_url_for_version "$CHANNEL_FOR_SYSTEM_x86_64_linux" "$version")"
-    sha_aarch64="$(prefetch_sha256 aarch64-linux "$version")"
+    url_aarch64="$(resolve_download_url_for_version "$CHANNEL_FOR_SYSTEM_aarch64_linux" "$version")"
+
+    sha_x86="$(prefetch_sha256 x86_64-linux "$url_x86")"
+    sha_aarch64="$(prefetch_sha256 aarch64-linux "$url_aarch64")"
 
     echo "x86_64-linux sha256: $sha_x86"
     echo "aarch64-linux sha256: $sha_aarch64"
@@ -132,6 +186,11 @@ update_release() {
   # - \`sha256\` values are Nix base32 hashes (as used by \`fetchurl { sha256 = "..."; }\`).
   version = "$version";
 
+  url = {
+    x86_64-linux = "$url_x86";
+    aarch64-linux = "$url_aarch64";
+  };
+
   sha256 = {
     x86_64-linux = "$sha_x86";
     aarch64-linux = "$sha_aarch64";