Fix download fallback handling

Author: wnlen

scripts/core/common.sh

@@ -824,7 +824,8 @@ download_mirror_score() {
   case "$fail_streak" in ''|*[!0-9]*) fail_streak=0 ;; esac
 
   if [ "$label" = "origin" ]; then
-    score=$((score + 5))
+    # Prefer GitHub mirrors by default; keep origin as the final fallback.
+    score=$((score - 300))
   fi
 
   if [ "$success_at" -gt 0 ]; then

scripts/core/config.sh

@@ -705,7 +705,7 @@ download_subscription_yaml() {
       __CLASH_DOWNLOAD_UA="$(subconverter_subscription_user_agent)" \
       download_subscription_file \
         "$url" \
-        "$out_file"
+        "$out_file" || return 1
 
       subscription_cache_store "$url" "$fmt" "$out_file" "$url"
       ;;

scripts/dev/check-download-mirror-priority.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_DIR="$(cd "$SCRIPT_DIR/../.." && pwd)"
+
+# shellcheck source=scripts/core/common.sh
+source "$PROJECT_DIR/scripts/core/common.sh"
+
+tmp_dir="$(mktemp -d)"
+trap 'rm -rf "$tmp_dir"' EXIT
+
+RUNTIME_DIR="$tmp_dir/runtime"
+mkdir -p "$RUNTIME_DIR"
+
+unset CLASH_GH_PROXY
+unset URL_GH_PROXY
+unset CLASH_GH_PROXY_POOL
+
+url="https://github.com/MetaCubeX/meta-rules-dat/releases/download/latest/country.mmdb"
+ordered_entries="$(
+  github_mirror_candidate_entries_ordered "$url" \
+    | sort -t'|' -k1,1nr \
+    | cut -d'|' -f2-
+)"
+
+first_label="$(printf '%s\n' "$ordered_entries" | head -n 1 | cut -d'|' -f1)"
+last_label="$(printf '%s\n' "$ordered_entries" | tail -n 1 | cut -d'|' -f1)"
+
+if [ "$first_label" != "gh-proxy" ]; then
+  echo "not ok - default mirror priority: first label is $first_label, expected gh-proxy" >&2
+  printf '%s\n' "$ordered_entries" >&2
+  exit 1
+fi
+
+if [ "$last_label" != "origin" ]; then
+  echo "not ok - default mirror priority: last label is $last_label, expected origin" >&2
+  printf '%s\n' "$ordered_entries" >&2
+  exit 1
+fi
+
+echo "ok - default GitHub downloads prefer mirrors before origin"

scripts/dev/check-subscription-download-failure.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_DIR="$(cd "$SCRIPT_DIR/../.." && pwd)"
+
+# shellcheck source=scripts/core/config.sh
+source "$PROJECT_DIR/scripts/core/config.sh"
+
+tmp_dir="$(mktemp -d)"
+trap 'rm -rf "$tmp_dir"' EXIT
+
+RUNTIME_DIR="$tmp_dir/runtime"
+mkdir -p "$RUNTIME_DIR"
+
+export CLASH_AUTO_UPDATE_SUBSCRIPTIONS="true"
+
+download_subscription_file() {
+  return 28
+}
+
+subscription_cache_store() {
+  echo "not ok - cache store called after failed subscription download" >&2
+  return 0
+}
+
+if download_subscription_yaml "https://example.invalid/sub" "$tmp_dir/sub.yaml" "manual-refresh"; then
+  echo "not ok - failed subscription download returned success" >&2
+  exit 1
+fi
+
+if [ -e "$tmp_dir/sub.yaml" ]; then
+  echo "not ok - failed subscription download left an output file" >&2
+  exit 1
+fi
+
+echo "ok - failed subscription download returns failure"