Fix certain invalid @lute/ runtime requires giving a nonsensical error (#280)

Author: ffrostfall

runtime/src/require.cpp

@@ -96,6 +96,11 @@ static luarequire_NavigateResult jump_to_alias(lua_State* L, void* ctx, const ch
         reqCtx->suffix = "";
         return NAVIGATE_SUCCESS;
     }
+    else if (std::string_view(path) == "$lute")
+    {
+        reqCtx->absPath = "@lute";
+        return NAVIGATE_SUCCESS;
+    }
 
     luarequire_NavigateResult result = storePathResult(reqCtx, getAbsolutePathResult(reqCtx->currentVFSType, path));
     if (result != NAVIGATE_SUCCESS)
@@ -111,6 +116,9 @@ static luarequire_NavigateResult to_parent(lua_State* L, void* ctx)
 {
     RequireCtx* reqCtx = static_cast<RequireCtx*>(ctx);
 
+    if (std::string_view(reqCtx->absPath) == "@lute")
+        luaL_error(L, "cannot get the parent of @lute");
+
     PathResult result = getParent(reqCtx->currentVFSType, reqCtx->absPath, reqCtx->relPath);
     if (result.status == PathResult::Status::NOT_FOUND)
     {
@@ -127,13 +135,21 @@ static luarequire_NavigateResult to_parent(lua_State* L, void* ctx)
 static luarequire_NavigateResult to_child(lua_State* L, void* ctx, const char* name)
 {
     RequireCtx* reqCtx = static_cast<RequireCtx*>(ctx);
+
+    if (std::string_view(reqCtx->absPath) == "@lute")
+        luaL_error(L, "'%s' is not a lute library", name);
+
     reqCtx->atFakeRoot = false;
     return storePathResult(reqCtx, getChild(reqCtx->currentVFSType, reqCtx->absPath, reqCtx->relPath, name));
 }
 
 static bool is_module_present(lua_State* L, void* ctx)
 {
     RequireCtx* reqCtx = static_cast<RequireCtx*>(ctx);
+
+    if (std::string_view(reqCtx->absPath) == "@lute")
+        luaL_error(L, "@lute is not requirable");
+
     return isFilePresent(reqCtx->currentVFSType, reqCtx->absPath, reqCtx->suffix);
 }
 
@@ -174,10 +190,11 @@ static luarequire_WriteResult get_config(lua_State* L, void* ctx, char* buffer,
     if (reqCtx->atFakeRoot)
     {
         std::string globalConfig = "{\n"
-                                    "    \"aliases\": {\n"
-                                    "        \"std\": \"$std\",\n"
-                                    "    }\n"
-                                    "}\n";
+                                   "    \"aliases\": {\n"
+                                   "        \"std\": \"$std\",\n"
+                                   "        \"lute\": \"$lute\",\n"
+                                   "    }\n"
+                                   "}\n";
         return write(globalConfig, buffer, buffer_size, size_out);
     }
 
@@ -186,15 +203,6 @@ static luarequire_WriteResult get_config(lua_State* L, void* ctx, char* buffer,
 
 static int load(lua_State* L, void* ctx, const char* path, const char* chunkname, const char* contents)
 {
-    std::string_view pathView = path;
-
-    if (pathView.rfind("@lute/", 0) == 0)
-    {
-        // @lute library tables are registered into require-by-string directly
-        // and are not loaded here.
-        luaL_error(L, "no luau runtime library: %s", path);
-    }
-
     // module needs to run in a new thread, isolated from the rest
     // note: we create ML on main thread so that it doesn't inherit environment of L
     lua_State* GL = lua_mainthread(L);
@@ -218,7 +226,7 @@ static int load(lua_State* L, void* ctx, const char* path, const char* chunkname
 
         if (status == 0)
         {
-            const std::string prefix = "module " + std::string(pathView) + " must";
+            const std::string prefix = "module " + std::string(path) + " must";
 
             if (lua_gettop(ML) == 0)
                 lua_pushstring(ML, (prefix + " return a value, if it has no return value, you should explicitly return `nil`\n").c_str());