Failed to load external module with turbopack

[Haaxor1689]

What version of Bun is running?

1.3.3

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What steps can reproduce the bug?

https://github.com/Haaxor1689/next-turbopack-issue-repro

1. bun i
2. bun --bun dev (--bun is important to run with bun runtime)
3. Open http://localhost:3000

What is the expected behavior?

Should load the module successfully

What do you see instead?

⨯ Error: Failed to load external module @aws-sdk/client-s3-ecbef8e33fd0b8f0: ResolveMessage: Cannot find module '@aws-sdk/client-s3-ecbef8e33fd0b8f0' from 'C:\Projects\reproduction-app\.next\dev\server\chunks\ssr\[root-of-the-server]__8c5801f7._.js'
    at module evaluation (file:\C:\Projects\reproduction-app\app\page.tsx:1:1)
    at module evaluation (C:\Projects\reproduction-app\.next\dev\server\chunks\ssr\[root-of-the-server]__1222724e._.js:39:47)
    at map (null)
    at processTicksAndRejections (null)
> 1 | import { S3 } from '@aws-sdk/client-s3';

Additional information

This issue was initially opened as a nextjs issue and was marked as fixed by this PR. It fixed the issue for node runtime but did not solve it for bun runtime. NextJs maintainer suggested to make this PR here.

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🔗 Similar & Duplicate Issues

Possible Duplicates

• oven-sh/bun#24184

Related Issues

• oven-sh/bun#23964
• oven-sh/bun#18065
• oven-sh/bun#24753

🔗 Related PRs

#22387 - Fix bundler assertion failure [merged] | src/bundler/linker_context/OutputFileListBuilder.zig:
"""

AI-generated summary of changes

• In take(...): After the assertion, a new line sets this.output_files.items.len = this.total_insertions to ensure the ArrayList's length reflects the actual inserted count and avoid undefined memory when returned.

• In calculateOutputFileListCapacity(...): Replaced the previous naive bytecode counting logic (which counted all chunks with chunk.content == .javascript) with a loader-aware approach. For each chunk, the code now derives a loader (from input_files.loader if the chunk has an entry point, otherwise defaulting to .js) and increments bytecode_count only if chunk.content == .javascript and the loader is JavaScript-like. The previous block of commented-out logic is removed in favor of this loader-aware check, altering how bytecode capacity is computed and thereby affecting the resulting capacity calculation.

Alterations to the declarations of exported or public entities

• None. There are no changes to public/exported function or type signatures in this diff. All modifications are internal logic changes within existing public functions.

Estimated code review effort: Medium
"""

---

src/bundler/linker_context/generateChunksInParallel.zig:
"""

AI-generated summary of changes

• Narrowed the Bytecode cache generation gate from checking only loader.isJavaScriptLike() to checking chunk.content == .javascript in addition to loader.isJavaScriptLike(). The rest of the Bytecode cache block remains unchanged, so the code path for generating and emitting bytecode is now executed only for JavaScript chunks, not for other chunk types.

Alterations to the declarations of exported or public entities

• None

Estimated code review effort: Medium
"""

---

test/bundler/bundler_compile.test.ts:
"""

AI-generated summary of changes

• The test file test/bundler/bundler_compile.test.ts now imports test from bun:test in addition to describe and expect, enabling use of the test() helper.
• The harness import from harness now includes bunEnv, bunExe, isWindows, tempDirWithFiles, extending the public API used by the test.
• A new test case named "does not crash" was added to the bundler suite. It creates a temporary directory via tempDirWithFiles("bundler-compile-shadcn", …) and populates it with frontend.tsx, index.html, and index.tsx containing a Bun server setup with several routes and development hot-reloading configuration.
• The test runs bun build with --compile --minify --sourcemap --bytecode using Bun.$ and the configured cwd and environment, asserting behavior via .throws(true).

Alterations to the declarations of exported or public entities

• Public export added: test in module bun:test (usage updated to import { describe, expect, test } from bun:test in test/bundler/bundler_compile.test.ts)
• Public exports added: bunEnv, bunExe, tempDirWithFiles in module harness (usage updated to import these symbols from harness in test/bundler/bundler_compile.test.ts)
  """
  Fix TypeScript syntax not working with 'ts' loader in BunPlugin #22460 - Fix TypeScript syntax not working with 'ts' loader in BunPlugin [merged] | src/bun.js/ModuleLoader.zig:
  """

AI-generated summary of changes

• Removed the runtime assertion requiring jsc_vm.plugin_runner to be non-null in Bun__transpileVirtualModule, replacing it with a comment explaining that the plugin runner is not required for virtual modules created via build.module(). The rest of the function remains unchanged; no public API signatures were modified. This means the function will no longer crash if plugin_runner is null, but the observable behavior of the transpilation path other than this guard is unchanged.

Alterations to the declarations of exported or public entities

• No exported/public signatures changed.

Estimated code review effort: Medium
"""

---

src/bun.js/bindings/headers-handwritten.h:
"""

AI-generated summary of changes

The BunLoaderType enum values were re-mapped to align with Zig's Loader enum values. All loader types except BunLoaderTypeNone are shifted from 0-based to 1-based indices: JSX 1 (was 0), JS 2 (was 1), TS 3 (was 2), TSX 4 (was 3), CSS 5 (was 4), FILE 6 (was 5), JSON 7 (was 6), JSONC 8 (was 7), TOML 9 (was 8), WASM 10 (was 9), NAPI 11 (was 10), YAML 19 (was 18). A new comment notes alignment with api/schema.zig. This changes the public API numeric values used for loader-type decisions; BunLoaderTypeNone (254) remains unchanged. No other logic or behavior is altered.

Alterations to the declarations of exported or public entities

• Constant declaration updated: const BunLoaderType BunLoaderTypeJSX in src/bun.js/bindings/headers-handwritten.h from 0 to 1
• Constant declaration updated: const BunLoaderType BunLoaderTypeJS in src/bun.js/bindings/headers-handwritten.h from 1 to 2
• Constant declaration updated: const BunLoaderType BunLoaderTypeTS in src/bun.js/bindings/headers-handwritten.h from 2 to 3
• Constant declaration updated: const BunLoaderType BunLoaderTypeTSX in src/bun.js/bindings/headers-handwritten.h from 3 to 4
• Constant declaration updated: const BunLoaderType BunLoaderTypeCSS in src/bun.js/bindings/headers-handwritten.h from 4 to 5
• Constant declaration updated: const BunLoaderType BunLoaderTypeFILE in src/bun.js/bindings/headers-handwritten.h from 5 to 6
• Constant declaration updated: const BunLoaderType BunLoaderTypeJSON in src/bun.js/bindings/headers-handwritten.h from 6 to 7
• Constant declaration updated: const BunLoaderType BunLoaderTypeJSONC in src/bun.js/bindings/headers-handwritten.h from 7 to 8
• Constant declaration updated: const BunLoaderType BunLoaderTypeTOML in src/bun.js/bindings/headers-handwritten.h from 8 to 9
• Constant declaration updated: const BunLoaderType BunLoaderTypeWASM in src/bun.js/bindings/headers-handwritten.h from 9 to 10
• Constant declaration updated: const BunLoaderType BunLoaderTypeNAPI in src/bun.js/bindings/headers-handwritten.h from 10 to 11
• Constant declaration updated: const BunLoaderType BunLoaderTypeYAML in src/bun.js/bindings/headers-handwritten.h from 18 to 19

Estimated code review effort: Medium
"""

---

test/regression/issue/12548.test.ts:
"""

AI-generated summary of changes

Adds a new test file test/regression/issue/12548.test.ts containing two regression tests to verify BunPlugin with the TypeScript loader ('ts') handles TypeScript syntax and type imports.

• Test 1 validates that a virtual module served via Bun.plugin with loader 'ts' can include TypeScript syntax (import { type TSchema } from '@sinclair/typebox'; export const test = 'works';) and that requiring the module results in stdout containing test: "works" with a clean exit (exit code 0) and no stderr.
• Test 2 validates type imports and type exports within a module provided by Bun.plugin using loader 'ts' (module defines a type, exports a type MyType and a value), requires the module, prints JSON.stringify(mod), and asserts exit code 0, nostderr, and stdout containing {"value":42}.

The tests use Bun.spawn to run the index.js files and inspect stdout, stderr, and exit codes to ensure correct behavior of the TypeScript loader under BunPlugin.

Alterations to the declarations of exported or public entities

• None

Estimated code review effort: Medium

• None

Estimated code review effort: Medium
"""

---

src/bun.js/bindings/BunPlugin.cpp:
"""

AI-generated summary of changes

The code path for removing a virtual module entry has been split into two explicit removals with per-step exception handling. Previously, the code removed from requireMap and esmRegistryMap via direct calls in sequence with a single final exception check. The new logic obtains requireMap, performs remove, and checks for exceptions before obtaining esmRegistryMap, performing its remove, and checking again. This introduces separate local pointers for each map and adds an additional RETURN_IF_EXCEPTION after the first removal and after obtaining the second map, ensuring finer-grained error handling. No other functional behavior or control flow beyond the staged removals and added exception checks changes.

Alterations to the declarations of exported or public entities

• No public API signature changes.

Estimated code review effort: Medium
"""
#23284 - fix(parser): typescript module parsing bug [merged] | src/ast/parseStmt.zig:
"""

AI-generated summary of changes

• The conditional branch that handles certain TypeScript namespace-related statements now requires there be no newline before the current token, in addition to the existing module/namespace scope and token checks. Specifically, the check adds !p.lexer.has_newline_before and keeps the same token conditions for identifier or string_literal with declare. This changes control flow to call parseTypeScriptNamespaceStmt(loc, opts) only when there is no newline preceding the token, tightening the context for "declare module" and related forms.

Alterations to the declarations of exported or public entities

none

Estimated code review effort: Medium
"""

---

test/regression/issue/22929-module-extensions-asi.test.ts:
"""

AI-generated summary of changes

Adds a regression test suite validating compatibility of Module._extensions with and without semicolons (ASI) when used under Bun. The tests dynamically create temporary directories and modules, then spawn a Bun process to execute test files that monkey-patch Module._extensions[".js"] to delegate to the original extension handler. The first test uses a module without semicolons and asserts that requiring it yields a function that equals itself and exposes a self-reference (result.f === result). The second test uses a module with semicolons and asserts that requiring it yields a function that returns 42 and that the function references itself via result.g === result. Both tests verify no parse errors appear in stderr and that the child process exits with code 0, with stdout printing "SUCCESS". The suite leverages Bun’s test harness and spawning facilities to validate runtime behavior with and without semicolon usage in modules.

Alterations to the declarations of exported or public entities

• none

Estimated code review effort: Medium
"""
#23916 - Fix Bun.build() compile API to properly apply sourcemaps [merged] | src/bun.js/api/JSBundler.zig:
"""

AI-generated summary of changes

• In JSBundler.zig, during the compile path, after computing and appending the base public path, the code now forces the sourcemap setting to .external whenever a compile run is active and a sourcemap is present. This overrides any other sourcemap type, ensuring only external sourcemaps are used when --compile is specified. This is guarded by checking source_map != .none and applies specifically to the compile flow.

• Changes do not modify any exported/public entity declarations or their signatures. No public API changes detected.

• Alterations to the declarations of exported or public entities

• No changes to exported/public signatures detected.

Estimated code review effort: Medium
"""

---

test/bundler/bun-build-compile-sourcemap.test.ts:
"""

AI-generated summary of changes

Adds a new test suite at test/bundler/bun-build-compile-sourcemap.test.ts to validate Bun.build with compile and various sourcemap options. The tests:

• Create temporary directories with helper files (helper.js, app.js) and, in one case, multiple source files (utils.js, helper.js, app.js).
• Build with compile: true and sourcemap set to inline, external, or true; verify a single output executable exists and runs.
• Execute the compiled binary, capture stderr, and assert that:
  • With sourcemaps enabled, error traces reference actual source files (helper.js, app.js, and utils.js where applicable).
  • Without sourcemaps, error traces reference bundled/virtual paths (e.g., /$bunfs/root/ or similar on Windows).
  • The process exits with a non-zero exit code (indicating the thrown error).
• Includes a test for compiling without sourcemaps to ensure bundled path references appear.
• Uses a harness for temporary directories and Bun.spawn to run executables, with assertions on error traces across scenarios.

Alterations to the declarations of exported or public entities

• No changes to declarations of exported or public entities detected.

Estimated code review effort: Medium
"""
#24389 - Clear module cache when require'ing an es module with TLA throws [merged] | src/js/builtins/CommonJS.ts:
"""

AI-generated summary of changes

• In loadEsmIntoCjs, when encountering a pending async module (state < ModuleLink with a pending fetch), a new cache cleanup step is added: delete registry.$delete(resolvedSpecifier) before throwing the TypeError about using await import().
• In the scenario where moduleRecordPromise is a Promise and either the state is Pending or the reactionsOrResult is a Promise, delete the resolvedSpecifier from the registry before throwing the same TypeError.
• After linkAndEvaluateModule returns a Promise, delete the resolvedSpecifier from the registry before throwing the same TypeError indicating that require() cannot load an async module and must use await import().

These changes insert cache invalidation in three additional branches to ensure the require cache is cleared when asynchronous ES module loading is involved, affecting error paths and top-level await handling.

Alterations to the declarations of exported or public entities

• None

Estimated code review effort: Medium

Manifest File Analyzer

Estimated code review effort: Medium
"""

---

test/regression/issue/24387.test.ts:
"""

AI-generated summary of changes

Adds a regression test file test/regression/issue/24387.test.ts that spawns a Bun subprocess to run a specific entry.js. It captures and asserts on both stdout and stderr, expecting no stderr, and stdout to match an inline snapshot containing a specific error message about using import() for async modules, followed by a Module object including a field foo: 67. It also asserts the spawned process exits with code 0. The test verifies the behavior of require()ing a module with TLA and subsequent module cache eviction to allow re-import.

Alterations to the declarations of exported or public entities

• No exported/public declarations were modified in this change.

Manifest File Analyzer

Estimated code review effort: Medium
"""

---

test/regression/issue/24387/entry.js:
"""

AI-generated summary of changes

Adds a new test script at test/regression/issue/24387/entry.js (Bun environment). The script attempts to require p.js, falls back to dynamic import on failure, and logs any error message with the resolved path masked. It notes (via a commented line) that deleting require.cache could fix the issue. After obtaining the listener, it unwraps nested default exports by repeatedly replacing listener with listener.default up to 5 times, then logs the final listener value. Includes error handling for the require attempt and a fallback to import, ensuring a single entrypoint can be resolved in both CommonJS and ESM interop contexts. Control flow: try require -> on error, print modified message and fallback to import -> unwrap default exports up to 5 levels -> console.log result.

Alterations to the declarations of exported or public entities

• Method added: None
• Method signature updated: None
• Variable renamed: None

Manifest File Analyzer

Estimated code review effort: Medium
"""

---

test/regression/issue/24387/p.js:
"""

AI-generated summary of changes

• Adds two lines to test/regression/issue/24387/p.js: a top-level await delay using setTimeout, and a new exported constant foo with the value 67. The top-level await introduces an asynchronous pause during module initialization; an exported public entity foo is now available from the module.

---

• Method added: export const foo in module test/regression/issue/24387/p.js (value: 67)

Alterations to the declarations of exported or public entities

• Method added: export const foo = 67 in module test/regression/issue/24387/p.js

Manifest File Analyzer

Estimated code review effort: Medium
"""

👤 Suggested Assignees

• robobun
• ahmafi
• maple146
• LarsKumbier
• harshmangalam

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[github-actions]

Found 2 possible duplicate issues:

1. Fail to load Prisma with Bun --bun next in Next.js 16 project #25032
2. ..Error: Failed to load chunk server/chunks/ssr/[root-of-the-server]__b20f0d68._.js from runtime #24753

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

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