Fix incorrect function.name for aliased imports

src/ec-evaluator/interpreter.ts

@@ -195,7 +195,9 @@ function evaluateImports(
           }
 
           declareIdentifier(context, spec.local.name, node, environment)
-          defineVariable(context, spec.local.name, functions[spec.imported.name], true, node)
+          const importedObj = functions[spec.imported.name]
+          Object.defineProperty(importedObj, 'name', { value: spec.local.name })
+          defineVariable(context, spec.local.name, importedObj, true, node)
         }
       }
     })

src/infiniteLoops/instrument.ts

@@ -587,7 +587,9 @@ async function handleImports(programs: es.Program[]): Promise<[string, string[]]
         }
       )
       program.body = (importsToAdd as es.Program['body']).concat(otherNodes)
-      const importedNames = importsToAdd.flatMap(node =>
+      const importedNames = (
+        importsToAdd.filter(node => node.type === 'VariableDeclaration') as es.VariableDeclaration[]
+      ).flatMap(node =>
         node.declarations.map(
           decl => ((decl.init as es.MemberExpression).object as es.Identifier).name
         )

src/infiniteLoops/runtime.ts

@@ -268,6 +268,7 @@ function prepareBuiltins(oldBuiltins: Map<string, any>) {
     }
   }
   newBuiltins.set('undefined', undefined)
+  newBuiltins.set('Object', Object)
   return newBuiltins
 }
 

src/runner/sourceRunner.ts

@@ -284,7 +284,7 @@ export async function sourceRunner(
     return runNative(program, context, theOptions)
   }
 
-  return runInterpreter(program!, context, theOptions)
+  return runInterpreter(program, context, theOptions)
 }
 
 export async function sourceFilesRunner(

src/transpiler/__tests__/modules.ts

@@ -11,12 +11,30 @@ import { transformImportDeclarations, transpile } from '../transpiler'
 jest.mock('../../modules/moduleLoaderAsync')
 jest.mock('../../modules/moduleLoader')
 
+// One import declaration is transformed into two AST nodes
+const IMPORT_DECLARATION_NODE_COUNT = 2
+
+test('Transform import declarations to correct number of nodes', async () => {
+  const code = stripIndent`
+    import { foo } from "one_module";
+  `
+  const context = mockContext(Chapter.SOURCE_4)
+  const program = parse(code, context)!
+  const [, importNodes] = await transformImportDeclarations(program, new Set<string>(), {
+    wrapSourceModules: true,
+    loadTabs: false,
+    checkImports: true
+  })
+  expect(importNodes.length).toEqual(IMPORT_DECLARATION_NODE_COUNT)
+})
+
 test('Transform import declarations into variable declarations', async () => {
   const code = stripIndent`
     import { foo } from "one_module";
     import { bar } from "another_module";
     foo(bar);
   `
+  const identifiers = ['foo', 'bar'] as const
   const context = mockContext(Chapter.SOURCE_4)
   const program = parse(code, context)!
   const [, importNodes] = await transformImportDeclarations(program, new Set<string>(), {
@@ -25,11 +43,33 @@ test('Transform import declarations into variable declarations', async () => {
     checkImports: true
   })
 
-  expect(importNodes[0].type).toBe('VariableDeclaration')
-  expect((importNodes[0].declarations[0].id as Identifier).name).toEqual('foo')
+  identifiers.forEach((ident, index) => {
+    const idx = IMPORT_DECLARATION_NODE_COUNT * index
+    expect(importNodes[idx].type).toBe('VariableDeclaration')
+    const node = importNodes[idx] as VariableDeclaration
+    expect((node.declarations[0].id as Identifier).name).toEqual(ident)
+  })
+})
+
+test('Transform import declarations with correctly aliased names (expression statements)', async () => {
+  const code = stripIndent`
+    import { foo } from "one_module";
+    import { bar as alias } from "another_module";
+    foo(bar);
+  `
+  const aliases = ['foo', 'alias'] as const
+  const context = mockContext(Chapter.SOURCE_4)
+  const program = parse(code, context)!
+  const [, importNodes] = await transformImportDeclarations(program, new Set<string>(), {
+    wrapSourceModules: true,
+    loadTabs: false,
+    checkImports: true
+  })
 
-  expect(importNodes[1].type).toBe('VariableDeclaration')
-  expect((importNodes[1].declarations[0].id as Identifier).name).toEqual('bar')
+  aliases.forEach((_, index) => {
+    const idx = IMPORT_DECLARATION_NODE_COUNT * index + 1
+    expect(importNodes[idx].type).toBe('ExpressionStatement')
+  })
 })
 
 test('Transpiler accounts for user variable names when transforming import statements', async () => {
@@ -54,7 +94,10 @@ test('Transpiler accounts for user variable names when transforming import state
 
   expect(importNodes[0].type).toBe('VariableDeclaration')
   expect(
-    ((importNodes[0].declarations[0].init as MemberExpression).object as Identifier).name
+    (
+      ((importNodes[0] as VariableDeclaration).declarations[0].init as MemberExpression)
+        .object as Identifier
+    ).name
   ).toEqual('__MODULE__1')
 
   expect(varDecl0.type).toBe('VariableDeclaration')
@@ -63,9 +106,12 @@ test('Transpiler accounts for user variable names when transforming import state
   expect(varDecl1.type).toBe('VariableDeclaration')
   expect(((varDecl1 as VariableDeclaration).declarations[0].init as Literal).value).toEqual('test1')
 
-  expect(importNodes[1].type).toBe('VariableDeclaration')
+  expect(importNodes[2].type).toBe('VariableDeclaration')
   expect(
-    ((importNodes[1].declarations[0].init as MemberExpression).object as Identifier).name
+    (
+      ((importNodes[2] as VariableDeclaration).declarations[0].init as MemberExpression)
+        .object as Identifier
+    ).name
   ).toEqual('__MODULE__3')
 })
 

src/transpiler/transpiler.ts

@@ -1,4 +1,4 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 import { generate } from 'astring'
 import * as es from 'estree'
 import { partition } from 'lodash'
@@ -63,7 +63,7 @@
   context?: Context,
   nativeId?: es.Identifier,
   useThis: boolean = false
-): Promise<[string, es.VariableDeclaration[], es.Program['body']]> {
+): Promise<[string, (es.VariableDeclaration | es.ExpressionStatement)[], es.Program['body']]> {
   const [importNodes, otherNodes] = partition(program.body, isImportDeclaration)
 
   if (importNodes.length === 0) return ['', [], otherNodes]
@@ -109,29 +109,49 @@
       }
 
       const declNodes = nodes.flatMap(({ specifiers }) =>
-        specifiers.map(spec => {
+        specifiers.flatMap(spec => {
           assert(spec.type === 'ImportSpecifier', `Expected ImportSpecifier, got ${spec.type}`)
 
           if (checkImports && !(spec.imported.name in docs!)) {
             throw new UndefinedImportError(spec.imported.name, moduleName, spec)
           }
 
-          // Convert each import specifier to its corresponding local variable declaration
-          return create.constantDeclaration(
-            spec.local.name,
-            create.memberExpression(
-              create.identifier(`${useThis ? 'this.' : ''}${namespaced}`),
-              spec.imported.name
+          return [
+            // Convert each import specifier to its corresponding local variable declaration
+            create.constantDeclaration(
+              spec.local.name,
+              create.memberExpression(
+                create.identifier(`${useThis ? 'this.' : ''}${namespaced}`),
+                spec.imported.name
+              )
+            ),
+            // Update the specifier's name property with the new name. This is so that calling
+            // `function.name` will return the aliased name. Equivalent to:
+            // Object.defineProperty(spec.imported.name, 'name', { value: spec.local.name });
+            create.expressionStatement(
+              create.callExpression(
+                create.memberExpression(create.identifier('Object'), 'defineProperty'),
+                [
+                  create.memberExpression(
+                    create.identifier(`${useThis ? 'this.' : ''}${namespaced}`),
+                    spec.imported.name
+                  ),
+                  create.literal('name'),
+                  create.objectExpression([
+                    create.property('value', create.literal(spec.local.name))
+                  ])
+                ]
+              )
             )
-          )
+          ]
         })
       )
 
-      return [moduleName, { text, nodes: declNodes, namespaced }] as [
+      return [moduleName, { text, nodes: declNodes, namespaced }] satisfies [
         string,
         {
           text: string
-          nodes: es.VariableDeclaration[]
+          nodes: (es.VariableDeclaration | es.ExpressionStatement)[]
           namespaced: string
         }
       ]