Add support for .config.luau

Author: JohnnyMorganz

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - The server now accepts DataModel information from the Studio Plugin even when there is no sourcemap present ([#1216](https://github.com/JohnnyMorganz/luau-lsp/pull/1216))
 - Added `luau-lsp.completion.imports.includedServices` and `luau-lsp.completion.imports.excludedServices` to configure what services show up during auto-importing. If non-empty, only the services listed in `includedServices` will show up. None of the services listed in `excludedServices` will ever show up.
 - Added support for inline documentation comments in global type definition files (relies on name being provided in settings, see below) ([#271](https://github.com/JohnnyMorganz/luau-lsp/issues/271))
+- Support processing `.config.luau` file as per [Luau-syntax configuration files RFC](https://rfcs.luau.org/config-luauconfig.html)
 
 ### Changed
 

src/WorkspaceFileResolver.cpp

@@ -2,6 +2,7 @@
 #include <unordered_map>
 #include <iostream>
 #include "Luau/Ast.h"
+#include "Luau/LuauConfig.h"
 #include "LSP/WorkspaceFileResolver.hpp"
 #include "LSP/Utils.hpp"
 
@@ -129,6 +130,18 @@ std::optional<std::string> WorkspaceFileResolver::parseConfig(const Uri& configP
     return Luau::parseConfig(contents, result, opts);
 }
 
+std::optional<std::string> WorkspaceFileResolver::parseLuauConfig(const Uri& configPath, const std::string& contents, Luau::Config& result)
+{
+    LUAU_ASSERT(configPath.parent());
+
+    Luau::ConfigOptions::AliasOptions aliasOpts;
+    aliasOpts.configLocation = configPath.parent()->fsPath();
+    aliasOpts.overwriteAliases = true;
+
+    // TODO: support interrupt callbacks based on TypeCheckLimits
+    return Luau::extractLuauConfig(contents, result, aliasOpts, Luau::InterruptCallbacks{});
+}
+
 const Luau::Config& WorkspaceFileResolver::readConfigRec(const Uri& uri) const
 {
     auto it = configCache.find(uri);
@@ -140,8 +153,33 @@ const Luau::Config& WorkspaceFileResolver::readConfigRec(const Uri& uri) const
         result = readConfigRec(*parent);
 
     auto configPath = uri.resolvePath(Luau::kConfigName);
+    auto luauConfigPath = uri.resolvePath(Luau::kLuauConfigName);
     auto robloxRcPath = uri.resolvePath(".robloxrc");
 
+    if (std::optional<std::string> contents = Luau::FileUtils::readFile(luauConfigPath.fsPath()))
+    {
+        std::optional<std::string> error = parseLuauConfig(configPath, *contents, result);
+        if (error)
+        {
+            if (client)
+            {
+                lsp::Diagnostic diagnostic{{{0, 0}, {0, 0}}};
+                diagnostic.message = *error;
+                diagnostic.severity = lsp::DiagnosticSeverity::Error;
+                diagnostic.source = "Luau";
+                client->publishDiagnostics({configPath, std::nullopt, {diagnostic}});
+            }
+            else
+                // TODO: this should never be reached anymore
+                std::cerr << configPath.toString() << ": " << *error;
+        }
+        else
+        {
+            if (client)
+                // Clear errors presented for file
+                client->publishDiagnostics({configPath, std::nullopt, {}});
+        }
+    }
     if (std::optional<std::string> contents = Luau::FileUtils::readFile(configPath.fsPath()))
     {
         std::optional<std::string> error = parseConfig(configPath, *contents, result);

src/include/LSP/WorkspaceFileResolver.hpp

@@ -96,7 +96,7 @@ struct WorkspaceFileResolver
 
     // Create a WorkspaceFileResolver with a specific default configuration
     explicit WorkspaceFileResolver(Luau::Config defaultConfig)
-        : defaultConfig(std::move(defaultConfig)){};
+        : defaultConfig(std::move(defaultConfig)) {};
 
     /// The file is managed by the client, so FS will be out of date
     const TextDocument* getTextDocument(const lsp::DocumentUri& uri) const;
@@ -116,6 +116,7 @@ struct WorkspaceFileResolver
     void clearConfigCache();
 
     static std::optional<std::string> parseConfig(const Uri& configPath, const std::string& contents, Luau::Config& result, bool compat = false);
+    static std::optional<std::string> parseLuauConfig(const Uri& configPath, const std::string& contents, Luau::Config& result);
 
 private:
     const Luau::Config& readConfigRec(const Uri& path) const;

tests/WorkspaceFileResolver.test.cpp

@@ -434,4 +434,24 @@ TEST_CASE_FIXTURE(Fixture, "resolve_toml_modules")
     CHECK_EQ(source->source, "--!strict\nreturn {[\"value\"] = 1;}");
 }
 
+TEST_CASE_FIXTURE(Fixture, "support_config_luau")
+{
+    TempDir t("file_resolver_supports_config_luau");
+    auto fooPath = t.touch_child("project/code/foo.luau");
+    auto luaurcPath = t.write_child("project/.config.luau", R"(
+        return {
+            luau = {
+                aliases = {
+                    test = "test"
+                }
+            }
+        }
+    )");
+
+    auto fooConfig = workspace.fileResolver.getConfig(workspace.fileResolver.getModuleName(Uri::file(fooPath)));
+
+    CHECK_EQ(fooConfig.aliases.size(), 1);
+    CHECK(fooConfig.aliases.find("test"));
+}
+
 TEST_SUITE_END();