refactor: rename default index from "mcpp-index" to "mcpplibs"

Align the default index name with kDefaultNamespace ("mcpplibs") so that
the canonical install directory path <ns>-x-<ns>.<short> and the fallback
path <indexName>-x-<fqname> naturally unify when the default namespace is
used.

Also fix a hardcoded "mcpp-index" literal in Fetcher::search() — now
uses cfg_.defaultIndex instead.

Author: Sunrisepeak

src/bmi_cache.cppm

@@ -28,7 +28,7 @@ export namespace mcpp::bmi_cache {
 struct CacheKey {
     std::filesystem::path mcppHome;
     std::string fingerprint;
-    std::string indexName;       // "mcpp-index" / "xim" / ...
+    std::string indexName;       // "mcpplibs" / "xim" / ...
     std::string packageName;     // "mcpplibs.cmdline"
     std::string version;         // "0.0.1"
 

src/cli.cppm

@@ -2019,7 +2019,7 @@ prepare_build(bool print_fingerprint,
             mcpp::lockfile::LockedPackage lp;
             lp.name    = name;
             lp.version = spec.version;
-            lp.source  = std::format("mcpp-index+{}",
+            lp.source  = std::format("mcpplibs+{}",
                                      "https://github.com/mcpp-community/mcpp-index.git");
             lp.hash    = "sha256:<from-xlings>";   // M3 will populate from install plan
             lock.packages.push_back(std::move(lp));

src/config.cppm

@@ -5,7 +5,7 @@
 //     bin/mcpp                  mcpp binary (self-contained mode)
 //     registry/                 XLINGS_HOME for mcpp's xlings
 //       bin/xlings              vendored xlings binary (= <XLINGS_HOME>/bin/xlings)
-//       .xlings.json            seeded with index_repos = [mcpp-index]
+//       .xlings.json            seeded with index_repos = [mcpplibs]
 //     bmi/<fp>/                 BMI cache (existing)
 //     cache/                    metadata caches
 //     config.toml               this module's input
@@ -47,7 +47,7 @@ struct GlobalConfig {
     std::filesystem::path           xlingsHomeOverride;  // empty = use registryDir
 
     // From config.toml [index]
-    std::string                     defaultIndex;        // "mcpp-index"
+    std::string                     defaultIndex;        // "mcpplibs"
     std::vector<IndexRepo>          indexRepos;
 
     // From config.toml [cache]
@@ -201,9 +201,9 @@ binary = "bundled"
 home   = ""
 
 [index]
-default = "mcpp-index"
+default = "mcpplibs"
 
-[index.repos."mcpp-index"]
+[index.repos."mcpplibs"]
 url = "https://github.com/mcpp-community/mcpp-index.git"
 # xlings auto-adds xim / awesome / scode / d2x as defaults.
 
@@ -597,7 +597,7 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
     cfg.xlingsBinaryMode = doc->get_string("xlings.binary").value_or("bundled");
     if (auto h = doc->get_string("xlings.home"); h && !h->empty())
         cfg.xlingsHomeOverride = *h;
-    cfg.defaultIndex   = doc->get_string("index.default").value_or("mcpp-index");
+    cfg.defaultIndex   = doc->get_string("index.default").value_or("mcpplibs");
     cfg.searchTtlSeconds = doc->get_int("cache.search_ttl_seconds").value_or(3600);
     cfg.defaultJobs    = doc->get_int("build.default_jobs").value_or(0);
     cfg.defaultBackend = doc->get_string("build.default_backend").value_or("ninja");
@@ -613,7 +613,7 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
             cfg.indexRepos.push_back({ name, it->second.as_string() });
         }
     }
-    // Defaults: only mcpp-index. xlings auto-adds its own standard
+    // Defaults: only mcpplibs. xlings auto-adds its own standard
     // defaults (xim / awesome / scode / d2x) because globalIndexRepos_
     // is non-empty (per xlings/src/core/config.cppm). Explicitly listing
     // them ourselves can cause cross-index name conflicts during
@@ -623,7 +623,7 @@ std::expected<GlobalConfig, ConfigError> load_or_init(
         for (auto& r : cfg.indexRepos) if (r.name == name) return;
         cfg.indexRepos.push_back({ std::string(name), std::string(url) });
     };
-    add_default("mcpp-index", "https://github.com/mcpp-community/mcpp-index.git");
+    add_default("mcpplibs", "https://github.com/mcpp-community/mcpp-index.git");
 
     // 5. Seed registry/.xlings.json if missing
     auto xjson = cfg.xlingsHome() / ".xlings.json";

src/pm/dep_spec.cppm

@@ -40,7 +40,7 @@ struct DependencySpec {
 };
 
 // Default namespace for packages declared without an explicit one — the
-// mcpp-index "root". Bare `gtest = "1.15.2"` becomes `(mcpp, gtest)`.
+// mcpplibs "root". Bare `gtest = "1.15.2"` becomes `(mcpp, gtest)`.
 inline constexpr std::string_view kDefaultNamespace = "mcpplibs";
 
 } // namespace mcpp::pm

src/pm/lock_io.cppm

@@ -18,7 +18,7 @@ export namespace mcpp::pm {
 struct LockedPackage {
     std::string name;
     std::string version;
-    std::string source;     // e.g. "mcpp-index+https://..." (M2 placeholder)
+    std::string source;     // e.g. "mcpplibs+https://..." (M2 placeholder)
     std::string hash;       // "sha256:..." or "fnv1a:..."
 };
 

src/pm/package_fetcher.cppm

@@ -92,7 +92,7 @@ public:
     // High-level helpers (parsed payload for common ops).
 
     struct SearchHit {
-        std::string source;       // "mcpp-index"
+        std::string source;       // "mcpplibs"
         std::string name;
         std::string description;
     };
@@ -479,7 +479,7 @@ Fetcher::search(std::string_view keyword) {
                 }
                 // record
                 if (!name.empty()) {
-                    hits.push_back({"mcpp-index", std::move(name), std::move(desc)});
+                    hits.push_back({cfg_.defaultIndex, std::move(name), std::move(desc)});
                 }
                 // advance past ]
                 while (p < items.size() && items[p] != ']') ++p;
@@ -657,7 +657,7 @@ Fetcher::read_xpkg_lua(std::string_view package_name) const
 namespace {
 
 struct ParsedTarget {
-    std::string indexName;       // "xim", "mcpp-index", or "" (default)
+    std::string indexName;       // "xim", "mcpplibs", or "" (default)
     std::string packageName;
     std::string version;
 };
@@ -696,7 +696,7 @@ Fetcher::resolve_xpkg_path(std::string_view target,
                            EventHandler* handler)
 {
     // Default to xim namespace for tools/toolchain. Modular libs use
-    // mcpp-index but consumers (cli) typically pass "<idx>:<name>@<ver>"
+    // mcpplibs but consumers (cli) typically pass "<idx>:<name>@<ver>"
     // explicitly anyway.
     auto parsed = parse_target(target, "xim");
     if (parsed.packageName.empty() || parsed.version.empty()) {
@@ -735,7 +735,7 @@ Fetcher::resolve_xpkg_path(std::string_view target,
         }
         XpkgPayload payload;
         // For xim packages (gcc, cmake, ...) the version dir IS the root.
-        // For mcpp-index packages the version dir contains an extracted
+        // For mcpplibs packages the version dir contains an extracted
         // tarball subdirectory; we treat the wrapper subdir as the root
         // when its content includes bin/ or include/.
         std::error_code ec;