From d580ff887efce2c43c3b8747d715685cd61a0527 Mon Sep 17 00:00:00 2001
From: sunrisepeak <speakshen@163.com>
Date: Wed, 24 Jun 2026 08:58:50 +0800
Subject: [PATCH] fix(index): refresh-on-miss covers version-miss, not just
 package-file-miss
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

WS3's offline-first gate (ensure_official_package_index_fresh) refreshes the
index only when the package *file* is missing locally. A stale-but-present
index file that lacks the requested *version* slipped through: e.g.
`mcpp toolchain install llvm@20.1.7` on a cached sandbox whose llvm.lua
predates 20.1.7 resolved to 'package xim:llvm@20.1.7 not found' and never
refreshed (ci-linux LLVM-toolchain step, post-#155).

Fix: in the install-failure path (exitCode != 0), refresh the xim index ONCE
before the existing direct-install retry. This is lazy refresh-on-miss —
steady-state installs (package+version already local) succeed first try and
never reach here, so they stay offline; an actual miss (package OR version)
now triggers one refresh + retry. Honors the '缺包/缺版本就刷新一次' intent
at the version level too.

Build: clean self-host.
---
 src/pm/package_fetcher.cppm | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/pm/package_fetcher.cppm b/src/pm/package_fetcher.cppm
index 1e9a2d2..e917e72 100644
--- a/src/pm/package_fetcher.cppm
+++ b/src/pm/package_fetcher.cppm
@@ -775,6 +775,23 @@ Fetcher::resolve_xpkg_path(std::string_view target,
             // for large toolchain packages and keeps the real failure output
             // visible to CI/users when it still fails.
             mcpp::fallback::clean_incomplete_install(verdir);
+
+            // Offline-first refresh-on-miss: the failure may be a stale local
+            // index that doesn't list this package@version (e.g. installing a
+            // NEW toolchain version when the cached index predates it). The
+            // pre-install gate only refreshes when the package *file* is
+            // missing, so a version-miss slips through. Refresh the index ONCE
+            // here — on an actual install miss — then retry. Steady-state
+            // installs (package+version already local) succeed on the first
+            // try and never reach this path, so they stay offline.
+            if (parsed.indexName == "xim") {
+                mcpp::xlings::Env refreshEnv{ cfg_.xlingsBinary, cfg_.xlingsHome() };
+                mcpp::log::verbose("fetcher",
+                    std::format("install failed for {}; refreshing index before retry",
+                                targets[0]));
+                mcpp::xlings::update_index(refreshEnv, /*quiet=*/true);
+            }
+
             mcpp::log::verbose("fetcher",
                 std::format("interface install failed for {}; retrying direct xlings install",
                             targets[0]));