Support require without extension for path requires

src/lune/globals/require/mod.rs

@@ -66,8 +66,6 @@ async fn require<'lua>(
 where
     'lua: 'static, // FIXME: Remove static lifetime bound here when builtin libraries no longer need it
 {
-    // TODO: Use proper lua strings, os strings, to avoid lossy conversions
-
     let source = source
         .to_str()
         .into_lua_err()

src/lune/globals/require/path.rs

@@ -1,3 +1,5 @@
+use std::path::{Path, PathBuf};
+
 use mlua::prelude::*;
 
 use super::context::*;
@@ -11,11 +13,63 @@ where
     'lua: 'ctx,
 {
     let (abs_path, rel_path) = ctx.resolve_paths(source, path)?;
-    if ctx.is_cached(&abs_path)? {
-        ctx.get_from_cache(&abs_path)
-    } else if ctx.is_pending(&abs_path)? {
+
+    // 1. Try to require the exact path
+    if let Ok(res) = require_inner(ctx, &abs_path, &rel_path).await {
+        return Ok(res);
+    }
+
+    // 2. Try to require the path with an added "luau" extension
+    let (luau_abs_path, luau_rel_path) = (
+        append_extension(&abs_path, "luau"),
+        append_extension(&rel_path, "luau"),
+    );
+    if let Ok(res) = require_inner(ctx, &luau_abs_path, &luau_rel_path).await {
+        return Ok(res);
+    }
+
+    // 2. Try to require the path with an added "lua" extension
+    let (lua_abs_path, lua_rel_path) = (
+        append_extension(&abs_path, "lua"),
+        append_extension(&rel_path, "lua"),
+    );
+    if let Ok(res) = require_inner(ctx, &lua_abs_path, &lua_rel_path).await {
+        return Ok(res);
+    }
+
+    // Nothing left to try, throw an error
+    Err(LuaError::runtime(format!(
+        "No file exist at the path '{}'",
+        rel_path.display()
+    )))
+}
+
+async fn require_inner<'lua, 'ctx>(
+    ctx: &'ctx RequireContext<'lua>,
+    abs_path: impl AsRef<Path>,
+    rel_path: impl AsRef<Path>,
+) -> LuaResult<LuaMultiValue<'lua>>
+where
+    'lua: 'ctx,
+{
+    let abs_path = abs_path.as_ref();
+    let rel_path = rel_path.as_ref();
+
+    if ctx.is_cached(abs_path)? {
+        ctx.get_from_cache(abs_path)
+    } else if ctx.is_pending(abs_path)? {
         ctx.wait_for_cache(&abs_path).await
     } else {
         ctx.load_with_caching(&abs_path, &rel_path).await
     }
 }
+
+fn append_extension(path: impl Into<PathBuf>, ext: &'static str) -> PathBuf {
+    let mut new = path.into();
+    match new.extension() {
+        // FUTURE: There's probably a better way to do this than converting to a lossy string
+        Some(e) => new.set_extension(format!("{}.{ext}", e.to_string_lossy())),
+        None => new.set_extension(ext),
+    };
+    new
+}