fix(formatter): use soft indent for empty objects in JSX spread attributes

crates/oxc_formatter/src/print/object_like.rs

@@ -72,6 +72,18 @@ impl<'a> ObjectLike<'a, '_> {
         }
     }
 
+    /// Check if the object is inside a JSX spread attribute or JSX spread child.
+    /// In these contexts, empty objects with comments should use soft line breaks
+    /// so they can stay on one line if they fit.
+    fn is_inside_jsx_spread(&self) -> bool {
+        match self {
+            Self::ObjectExpression(o) => {
+                matches!(o.parent, AstNodes::JSXSpreadAttribute(_) | AstNodes::JSXSpreadChild(_))
+            }
+            Self::TSTypeLiteral(_) => false,
+        }
+    }
+
     fn write_members(&self, f: &mut Formatter<'_, 'a>) {
         match self {
             Self::ObjectExpression(o) => o.properties().fmt(f),
@@ -87,7 +99,15 @@ impl<'a> Format<'a> for ObjectLike<'a, '_> {
         write!(f, "{");
 
         if self.members_are_empty() {
-            write!(f, format_dangling_comments(self.span()).with_block_indent());
+            // In JSX spread attributes/children, use soft indent so the object
+            // can stay on one line if it fits (e.g., `<div {...{/* comment */}} />`).
+            // In other contexts like variable declarations, use block indent to
+            // expand the object (e.g., `var a = {\n  /* comment */\n};`).
+            if self.is_inside_jsx_spread() {
+                write!(f, format_dangling_comments(self.span()).with_soft_block_indent());
+            } else {
+                write!(f, format_dangling_comments(self.span()).with_block_indent());
+            }
         } else {
             let should_insert_space_around_brackets = f.options().bracket_spacing.value();
             let should_expand =

tasks/prettier_conformance/snapshots/prettier.js.snap.md

@@ -1,4 +1,4 @@
-js compatibility: 743/761 (97.63%)
+js compatibility: 744/761 (97.77%)
 
 # Failed
 
@@ -20,5 +20,4 @@ js compatibility: 743/761 (97.63%)
 | js/sequence-expression/ignored.js | 💥 | 25.00% |
 | js/strings/template-literals.js | 💥💥 | 98.01% |
 | jsx/fbt/test.js | 💥 | 84.06% |
-| jsx/ignore/spread.js | 💥 | 83.33% |
 | jsx/jsx/quotes.js | 💥💥💥💥 | 79.41% |

tasks/prettier_conformance/snapshots/prettier.ts.snap.md

@@ -1,11 +1,10 @@
-ts compatibility: 579/606 (95.54%)
+ts compatibility: 580/606 (95.71%)
 
 # Failed
 
 | Spec path | Failed or Passed | Match ratio |
 | :-------- | :--------------: | :---------: |
 | jsx/fbt/test.js | 💥 | 84.06% |
-| jsx/ignore/spread.js | 💥 | 83.33% |
 | jsx/jsx/quotes.js | 💥💥💥💥 | 79.41% |
 | typescript/arrow/comments.ts | 💥✨ | 44.44% |
 | typescript/arrow/comments/issue-11100.ts | 💥 | 84.00% |