fix(lint): do not convert empty object types to interfaces

.changeset/angry-parts-change.md

@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#8759](https://github.com/biomejs/biome/issues/8759): The [`useConsistentTypeDefinitions`](https://biomejs.dev/linter/rules/use-consistent-type-definitions/) rule no longer converts empty object type declarations into interfaces, as it will conflict with the [`noEmptyInterface`](https://biomejs.dev/linter/rules/no-empty-interface/) rule and can cause an infinite loop when both rules are enabled.

crates/biome_js_analyze/src/lint/style/use_consistent_type_definitions.rs

@@ -23,6 +23,9 @@ declare_lint_rule! {
     /// Consistent type definition styles, aside from improving code readability, help minimize cognitive load when developers
     /// switch between different codebases or within a large codebase.
     ///
+    /// Empty object type declarations will be left as-is and will not be converted to interfaces,
+    /// as it will conflict with the `noEmptyInterface` rule.
+    ///
     /// ## Example
     ///
     /// ### Invalid
@@ -40,6 +43,10 @@ declare_lint_rule! {
     /// }
     /// ```
     ///
+    /// ```ts
+    /// type AnyObject = {};
+    /// ```
+    ///
     /// ## Options
     ///
     /// The following options are available
@@ -180,8 +187,16 @@ fn can_convert_interface_to_type(interface_decl: &TsInterfaceDeclaration) -> boo
 fn can_convert_type_to_interface(type_alias: &TsTypeAliasDeclaration) -> bool {
     // Check if the type alias has type parameters
     // Type aliases with complex types cannot be converted to interfaces
+    let Ok(AnyTsType::TsObjectType(ty)) = type_alias.ty() else {
+        return false;
+    };
 
-    matches!(type_alias.ty(), Ok(AnyTsType::TsObjectType(_)))
+    // Converting empty types into interfaces will conflict with the `noEmptyInterface` rule
+    if ty.members().is_empty() {
+        return false;
+    }
+
+    true
 }
 
 fn convert_interface_to_type_alias(

crates/biome_js_analyze/tests/specs/style/useConsistentTypeDefinitions/valid.ts

@@ -38,4 +38,7 @@ type Nullable<T> = T | null;
 // Interfaces can extend
 interface ExtendedInterface extends Foo {
     extra: boolean;
-}
+}
+
+// Empty types will be left as-is
+type AnyObject = {};

crates/biome_js_analyze/tests/specs/style/useConsistentTypeDefinitions/valid.ts.snap

@@ -45,4 +45,8 @@ type Nullable<T> = T | null;
 interface ExtendedInterface extends Foo {
     extra: boolean;
 }
+
+// Empty types will be left as-is
+type AnyObject = {};
+
 ```