Implement functionality necessary for relative path requires

src/lune/globals/require/context.rs

@@ -12,7 +12,7 @@ const REGISTRY_KEY: &str = "RequireContext";
 
 #[derive(Debug, Clone)]
 pub(super) struct RequireContext {
-    use_absolute_paths: bool,
+    use_cwd_relative_paths: bool,
     working_directory: PathBuf,
     cache_builtins: Arc<AsyncMutex<HashMap<LuneBuiltin, LuaResult<LuaRegistryKey>>>>,
     cache_results: Arc<AsyncMutex<HashMap<PathBuf, LuaResult<LuaRegistryKey>>>>,
@@ -30,9 +30,9 @@ impl RequireContext {
     pub fn new() -> Self {
         let cwd = env::current_dir().expect("Failed to get current working directory");
         Self {
-            // TODO: Set to false by default, load some kind of config
-            // or env var to check if we should be using absolute paths
-            use_absolute_paths: true,
+            // FUTURE: We could load some kind of config or env var
+            // to check if we should be using cwd-relative paths
+            use_cwd_relative_paths: false,
             working_directory: cwd,
             cache_builtins: Arc::new(AsyncMutex::new(HashMap::new())),
             cache_results: Arc::new(AsyncMutex::new(HashMap::new())),
@@ -41,10 +41,10 @@ impl RequireContext {
     }
 
     /**
-        If `require` should use absolute paths or not.
+        If `require` should use cwd-relative paths or not.
     */
-    pub fn use_absolute_paths(&self) -> bool {
-        self.use_absolute_paths
+    pub fn use_cwd_relative_paths(&self) -> bool {
+        self.use_cwd_relative_paths
     }
 
     /**

src/lune/globals/require/mod.rs

@@ -1,6 +1,6 @@
 use mlua::prelude::*;
 
-use crate::lune::scheduler::LuaSchedulerExt;
+use crate::lune::{scheduler::LuaSchedulerExt, util::TableBuilder};
 
 mod context;
 use context::RequireContext;
@@ -10,9 +10,69 @@ mod alias;
 mod builtin;
 mod relative;
 
+const REQUIRE_IMPL: &str = r#"
+return require(source(), ...)
+"#;
+
 pub fn create(lua: &'static Lua) -> LuaResult<impl IntoLua<'_>> {
     lua.set_app_data(RequireContext::new());
-    lua.create_async_function(|lua, path: LuaString| async move {
+
+    /*
+        Require implementation needs a few workarounds:
+
+        - Async functions run outside of the lua resumption cycle,
+          so the current lua thread, as well as its stack/debug info
+          is not available, meaning we have to use a normal function
+
+        - Using the async require function directly in another lua function
+          would mean yielding across the metamethod/c-call boundary, meaning
+          we have to first load our two functions into a normal lua chunk
+          and then load that new chunk into our final require function
+
+        Also note that we inspect the stack at level 2:
+
+        1. The current c / rust function
+        2. The wrapper lua chunk defined above
+        3. The lua chunk we are require-ing from
+    */
+
+    let require_fn = lua.create_async_function(require)?;
+    let get_source_fn = lua.create_function(move |lua, _: ()| match lua.inspect_stack(2) {
+        None => Err(LuaError::runtime(
+            "Failed to get stack info for require source",
+        )),
+        Some(info) => match info.source().source {
+            None => Err(LuaError::runtime(
+                "Stack info is missing source for require",
+            )),
+            Some(source) => lua.create_string(source.as_bytes()),
+        },
+    })?;
+
+    let require_env = TableBuilder::new(lua)?
+        .with_value("source", get_source_fn)?
+        .with_value("require", require_fn)?
+        .build_readonly()?;
+
+    lua.load(REQUIRE_IMPL)
+        .set_name("require")
+        .set_environment(require_env)
+        .into_function()
+}
+
+async fn require<'lua>(
+    lua: &'lua Lua,
+    (source, path): (LuaString<'lua>, LuaString<'lua>),
+) -> LuaResult<LuaMultiValue<'lua>>
+where
+    'lua: 'static, // FIXME: Remove static lifetime bound here when builtin libraries no longer need it
+{
+    let source = source
+        .to_str()
+        .into_lua_err()
+        .context("Failed to parse require source as string")?
+        .to_string();
+
     let path = path
         .to_str()
         .into_lua_err()
@@ -23,7 +83,7 @@ pub fn create(lua: &'static Lua) -> LuaResult<impl IntoLua<'_>> {
         .app_data_ref()
         .expect("Failed to get RequireContext from app data");
 
-        let res = if let Some(builtin_name) = path
+    if let Some(builtin_name) = path
         .strip_prefix("@lune/")
         .map(|name| name.to_ascii_lowercase())
     {
@@ -33,12 +93,9 @@ pub fn create(lua: &'static Lua) -> LuaResult<impl IntoLua<'_>> {
             "Require with custom alias must contain '/' delimiter",
         ))?;
         alias::require(lua, &context, alias, name).await
-        } else if context.use_absolute_paths() {
+    } else if context.use_cwd_relative_paths() {
         absolute::require(lua, &context, &path).await
     } else {
-            relative::require(lua, &context, &path).await
-        };
-
-        res.clone()
-    })
+        relative::require(lua, &context, &source, &path).await
+    }
 }

src/lune/globals/require/relative.rs

@@ -5,12 +5,13 @@ use super::context::*;
 pub(super) async fn require<'lua, 'ctx>(
     _lua: &'lua Lua,
     _ctx: &'ctx RequireContext,
+    source: &str,
     path: &str,
 ) -> LuaResult<LuaMultiValue<'lua>>
 where
     'lua: 'ctx,
 {
     Err(LuaError::runtime(format!(
-        "TODO: Support require for absolute paths (tried to require '{path}')"
+        "TODO: Support require for absolute paths (tried to require '{path}' from '{source}')"
     )))
 }