From 1e1d1f58e9bb9b196ec983a0d4bde605d6fbdd0f Mon Sep 17 00:00:00 2001
From: "Roni N. (Kittenz)" <catmaster.kissa@gmail.com>
Date: Sat, 6 Nov 2021 04:11:26 +0200
Subject: [PATCH] Look for `.luau` before `.lua` in REPL & Analyze (#97) (#124)

As discussed in the issue, Luau has evolved from Lua to the point
where a new default extension `.luau` would be needed.

This change makes the REPL and Analyze look for `.luau`
extension first and if not found, fall back to `.lua`.
---
 CLI/Analyze.cpp | 18 ++++++++++++++----
 CLI/Repl.cpp    | 10 ++++++----
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/CLI/Analyze.cpp b/CLI/Analyze.cpp
index ed0552d..d72a865 100644
--- a/CLI/Analyze.cpp
+++ b/CLI/Analyze.cpp
@@ -115,7 +115,12 @@ struct CliFileResolver : Luau::FileResolver
     {
         if (Luau::AstExprConstantString* expr = node->as<Luau::AstExprConstantString>())
         {
-            Luau::ModuleName name = std::string(expr->value.data, expr->value.size) + ".lua";
+            Luau::ModuleName name = std::string(expr->value.data, expr->value.size) + ".luau";
+            if (!moduleExists(name))
+            {
+                // fall back to .lua if a module with .luau doesn't exist
+                name = std::string(expr->value.data, expr->value.size) + ".lua";
+            }
 
             return {{name}};
         }
@@ -236,8 +241,15 @@ int main(int argc, char** argv)
         if (isDirectory(argv[i]))
         {
             traverseDirectory(argv[i], [&](const std::string& name) {
-                if (name.length() > 4 && name.rfind(".lua") == name.length() - 4)
+                // Look for .luau first and if absent, fall back to .lua
+                if (name.length() > 5 && name.rfind(".luau") == name.length() - 5)
+                {
                     failed += !analyzeFile(frontend, name.c_str(), format, annotate);
+                }
+                else if (name.length() > 4 && name.rfind(".lua") == name.length() - 4)
+                {
+                    failed += !analyzeFile(frontend, name.c_str(), format, annotate);
+                }
             });
         }
         else
@@ -256,5 +268,3 @@ int main(int argc, char** argv)
 
     return (format == ReportFormat::Luacheck) ? 0 : failed;
 }
-
-
diff --git a/CLI/Repl.cpp b/CLI/Repl.cpp
index 4968d08..323ab14 100644
--- a/CLI/Repl.cpp
+++ b/CLI/Repl.cpp
@@ -51,9 +51,13 @@ static int lua_require(lua_State* L)
         return finishrequire(L);
     lua_pop(L, 1);
 
-    std::optional<std::string> source = readFile(name + ".lua");
+    std::optional<std::string> source = readFile(name + ".luau");
     if (!source)
-        luaL_argerrorL(L, 1, ("error loading " + name).c_str());
+    {
+        source = readFile(name + ".lua"); // try .lua if .luau doesn't exist
+        if (!source)
+            luaL_argerrorL(L, 1, ("error loading " + name).c_str()); // if neither .luau nor .lua exist, we have an error
+    }
 
     // module needs to run in a new thread, isolated from the rest
     lua_State* GL = lua_mainthread(L);
@@ -511,5 +515,3 @@ int main(int argc, char** argv)
         return failed;
     }
 }
-
-