fix(transform): keep enum references out of cross-module inlining

changelog.d/10417-cross-module-enum-inlining.md

@@ -0,0 +1,6 @@
+Cross-module inlining now keeps functions and methods that reference TypeScript
+enum members in their source module. Previously, copying such a body into an
+importer made code generation resolve the enum against the importer's enum
+table, causing compilation to fail with `enum member X.Y not found in enums
+table`. This unblocks packages such as cheerio that use small exported helpers
+backed by module-local enums (#10417).

crates/perry-transform/src/inline/cross_module.rs

@@ -20,6 +20,7 @@ pub fn is_cross_module_safe(body: &[Stmt]) -> bool {
             | Expr::ExternFuncRef { .. }
             | Expr::GlobalGet(_)
             | Expr::GlobalSet(_, _)
+            | Expr::EnumMember { .. }
             | Expr::NativeModuleRef(_) => false,
             // Closures are out of scope for cross-module inlining: the
             // closure body has its own LocalIds, captures lists, and may
@@ -396,6 +397,7 @@ fn cross_function_expr_is_safe(
         }
         Expr::GlobalGet(_)
         | Expr::GlobalSet(_, _)
+        | Expr::EnumMember { .. }
         | Expr::NativeModuleRef(_)
         // These nodes carry source-module-relative path sets. Codegen resolves
         // those sets through the current module's dynamic-target map, so a
@@ -1181,6 +1183,7 @@ pub fn is_cross_module_safe_with_externs(body: &[Stmt], extern_names: &mut Vec<S
             Expr::FuncRef(_)
             | Expr::GlobalGet(_)
             | Expr::GlobalSet(_, _)
+            | Expr::EnumMember { .. }
             | Expr::NativeModuleRef(_) => false,
             Expr::Closure { .. } => false,
             Expr::ExternFuncRef { name, .. } => {

crates/perry-transform/src/inline/mod.rs

@@ -1486,6 +1486,42 @@ mod tests {
         assert!(gather_cross_module_functions(&source).is_empty());
     }
 
+    #[test]
+    fn cross_module_enum_members_stay_in_the_source_module() {
+        let enum_member = Expr::EnumMember {
+            enum_name: "CharacterCode".to_string(),
+            member_name: "Lt".to_string(),
+        };
+
+        let mut source = Module::new("/src/utils.ts");
+        let mut helper = function(1, vec![Stmt::Return(Some(enum_member.clone()))]);
+        helper.name = "isHtml".to_string();
+        helper.is_exported = true;
+        source.functions.push(helper.clone());
+        source
+            .exported_functions
+            .push(("isHtml".to_string(), helper.id));
+
+        assert!(
+            gather_cross_module_functions(&source).is_empty(),
+            "free functions that depend on a source enum must remain outlined"
+        );
+
+        let mut class = anon_class(2, "Probe");
+        class.is_exported = true;
+        class.methods.push(helper);
+        source.classes.push(class);
+
+        assert!(
+            gather_cross_module_methods(&source).is_empty(),
+            "strict method harvesting must reject source enum references"
+        );
+        assert!(
+            gather_cross_module_methods_with_extern_imports(&source).is_empty(),
+            "extern-aware method harvesting must reject source enum references"
+        );
+    }
+
     #[test]
     fn cross_module_free_function_with_dynamic_require_is_rejected() {
         let mut source = Module::new("/src/package/index.ts");

crates/perry/tests/source_graph_export_regressions.rs

@@ -972,3 +972,5 @@ mod issue_10180;
 mod issue_10197;
 #[path = "source_graph_export_regressions/issue_10258.rs"]
 mod issue_10258;
+#[path = "source_graph_export_regressions/issue_10417.rs"]
+mod issue_10417;

crates/perry/tests/source_graph_export_regressions/issue_10417.rs

@@ -0,0 +1,34 @@
+use super::{compile_and_run, write};
+
+#[test]
+fn enum_members_are_not_copied_into_importing_modules() {
+    let dir = tempfile::tempdir().expect("tempdir");
+    write(
+        dir.path(),
+        "utils.ts",
+        "enum CharacterCode { LowerA = 97, LowerZ = 122, Lt = 60 }\n\
+         export function isHtml(str: string): boolean {\n\
+           const c = str.charCodeAt(1);\n\
+           return str.charCodeAt(0) === CharacterCode.Lt &&\n\
+             c >= CharacterCode.LowerA && c <= CharacterCode.LowerZ;\n\
+         }\n\
+         export class Probe {\n\
+           isLt(str: string): boolean {\n\
+             return str.charCodeAt(0) === CharacterCode.Lt;\n\
+           }\n\
+         }\n",
+    );
+    write(
+        dir.path(),
+        "main.ts",
+        "import { isHtml, Probe } from './utils';\n\
+         console.log(isHtml('<div>'), isHtml('hello'));\n\
+         const probe = new Probe();\n\
+         console.log(probe.isLt('<a'), probe.isLt('a'));\n",
+    );
+
+    assert_eq!(
+        compile_and_run(dir.path(), "main.ts"),
+        "true false\ntrue false\n"
+    );
+}