Target first attribute at_sign in stmt_remove_leading_newlines for LocalFunction/ConstFunction (#1115)

* fix: target first attribute at_sign in stmt_remove_leading_newlines for LocalFunction/ConstFunction

When a LocalFunction or ConstFunction has a leading Luau attribute (e.g. @Native),
the actual first token of the statement is the attribute's at_sign, not the local/const
keyword. stmt_remove_leading_newlines was targeting the wrong token, leaving stray
newlines before the attribute at the start of a block.

Fixes #1109

* simplify: extract strip_attribute_leading_newlines helper, avoid allocation on no-attribute path

- Deduplicate the identical 6-line attribute-stripping logic from LocalFunction
  and ConstFunction arms into a single helper function
- Use peekable iterator so no Vec is allocated when the function has no attributes
  (the common case)
- Make both arms use a consistent if-let pattern instead of early-return vs if/else
- Remove redundant comment from test input file

* refactor: use next() to own first attribute, eliminating index and clone

Replace peek()+collect()+[0]+clone() with cloned().next()? which takes the
first element as an owned value so with_at_sign can consume it directly.

* style: rustfmt

* docs: add changelog entry for #1109

Author: JohnnyMorganz

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fixed npm publishing by bumping Node.js from 16 to 22 in CI workflows to support npm trusted publishing
 - Luau: Fixed union/intersection type definitions not being hung when the type alone fits within the column width but the full line (including ` = `) exceeds it ([#1104](https://github.com/JohnnyMorganz/StyLua/issues/1104))
+- Luau: Fixed stray leading newlines not being removed from `local function` and `const function` declarations that have attributes (e.g. `@native`) at the start of a block ([#1109](https://github.com/JohnnyMorganz/StyLua/issues/1109))
 
 ## [2.4.1] - 2026-04-06
 

src/formatters/block.rs

@@ -18,6 +18,8 @@ use crate::{
     },
     shape::Shape,
 };
+#[cfg(feature = "luau")]
+use full_moon::ast::luau::LuauAttribute;
 use full_moon::ast::{
     punctuated::Punctuated, Block, Expression, LastStmt, Prefix, Return, Stmt, Var,
 };
@@ -317,6 +319,20 @@ fn var_remove_leading_newline(var: Var) -> Var {
     }
 }
 
+#[cfg(feature = "luau")]
+fn strip_attribute_leading_newlines<'a>(
+    attributes: impl Iterator<Item = &'a LuauAttribute>,
+) -> Option<Vec<LuauAttribute>> {
+    let mut cloned = attributes.cloned();
+    let first = cloned.next()?;
+    let at_sign = first.at_sign();
+    let leading_trivia = trivia_remove_leading_newlines(at_sign.leading_trivia().collect());
+    let new_at_sign = at_sign.update_leading_trivia(FormatTriviaType::Replace(leading_trivia));
+    let mut result = vec![first.with_at_sign(new_at_sign)];
+    result.extend(cloned);
+    Some(result)
+}
+
 fn stmt_remove_leading_newlines(stmt: Stmt) -> Stmt {
     match stmt {
         Stmt::Assignment(assignment) => {
@@ -363,12 +379,19 @@ fn stmt_remove_leading_newlines(stmt: Stmt) -> Stmt {
             local_assignment.local_token(),
             with_local_token
         ),
-        Stmt::LocalFunction(local_function) => update_first_token!(
-            LocalFunction,
-            local_function,
-            local_function.local_token(),
-            with_local_token
-        ),
+        Stmt::LocalFunction(local_function) => {
+            #[cfg(feature = "luau")]
+            if let Some(attributes) = strip_attribute_leading_newlines(local_function.attributes())
+            {
+                return Stmt::LocalFunction(local_function.with_attributes(attributes));
+            }
+            update_first_token!(
+                LocalFunction,
+                local_function,
+                local_function.local_token(),
+                with_local_token
+            )
+        }
         Stmt::NumericFor(numeric_for) => update_first_token!(
             NumericFor,
             numeric_for,
@@ -404,12 +427,19 @@ fn stmt_remove_leading_newlines(stmt: Stmt) -> Stmt {
             with_const_token
         ),
         #[cfg(feature = "luau")]
-        Stmt::ConstFunction(const_function) => update_first_token!(
-            ConstFunction,
-            const_function,
-            const_function.const_token(),
-            with_const_token
-        ),
+        Stmt::ConstFunction(const_function) => {
+            if let Some(attributes) = strip_attribute_leading_newlines(const_function.attributes())
+            {
+                Stmt::ConstFunction(const_function.with_attributes(attributes))
+            } else {
+                update_first_token!(
+                    ConstFunction,
+                    const_function,
+                    const_function.const_token(),
+                    with_const_token
+                )
+            }
+        }
 
         #[cfg(feature = "luau")]
         Stmt::ExportedTypeDeclaration(exported_type_declaration) => update_first_token!(

tests/inputs-luau/attributes-4.lua

@@ -0,0 +1,13 @@
+do
+
+@native
+local function foo()
+end
+end
+
+do
+
+@native
+const function bar()
+end
+end

tests/snapshots/tests__luau@attributes-4.lua.snap

@@ -0,0 +1,15 @@
+---
+source: tests/tests.rs
+assertion_line: 36
+expression: "format(&contents, LuaVersion::Luau)"
+input_file: tests/inputs-luau/attributes-4.lua
+---
+do
+	@native
+	local function foo() end
+end
+
+do
+	@native
+	const function bar() end
+end