From cdc39bb0501a3e1b8c26cdf5ac0b2806c81bdbf5 Mon Sep 17 00:00:00 2001
From: Dylan Conway <dylan.conway567@gmail.com>
Date: Sat, 25 Apr 2026 10:08:53 -0700
Subject: [PATCH] resolver: add bun:main to HardcodedModule.Alias so it isn't
 auto-installed

`bun:main` was in `HardcodedModule.map` but missing from
`Alias.bun_extra_alias_kvs`, so the runtime transpiler's import-record
pass (RuntimeTranspilerStore.zig:534) didn't recognise it as a builtin
and stripped the `bun:` prefix, leaving a bare `import("main")` in the
emitted JS. At runtime that fell through `_resolve` to
`resolveAndAutoInstall`, which fetched the npm `main` package over the
network. The bun-main-entry-point tests "passed" by loading that npm
package and flaked whenever the registry fetch was slow or failed.

Adding the alias keeps the specifier intact so it round-trips through
the existing `_resolve` / `getHardcodedModule` paths and resolves to the
ServerEntryPoint wrapper as intended.

Also harden the tests: disable auto-install via an empty package.json,
assert the wrapper namespace has no exports (the npm package has four),
collapse the assertions into one toEqual so a future failure surfaces
stderr/exit/signal, and update the preload test's expected output order
now that import("bun:main") actually evaluates the wrapper (entry runs
before the preload's await resumes).
---
 src/bun.js/HardcodedModule.zig                |  1 +
 .../bun/resolve/bun-main-entry-point.test.ts  | 32 ++++++++++++++-----
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/src/bun.js/HardcodedModule.zig b/src/bun.js/HardcodedModule.zig
index 84f6ff99686..1fb28dabf43 100644
--- a/src/bun.js/HardcodedModule.zig
+++ b/src/bun.js/HardcodedModule.zig
@@ -365,6 +365,7 @@ pub const HardcodedModule = enum {
             .{ "bun:app", .{ .path = "bun:app" } },
             .{ "bun:ffi", .{ .path = "bun:ffi" } },
             .{ "bun:jsc", .{ .path = "bun:jsc" } },
+            .{ "bun:main", .{ .path = "bun:main" } },
             .{ "bun:sqlite", .{ .path = "bun:sqlite" } },
             .{ "bun:wrap", .{ .path = "bun:wrap" } },
             .{ "bun:internal-for-testing", .{ .path = "bun:internal-for-testing" } },
diff --git a/test/js/bun/resolve/bun-main-entry-point.test.ts b/test/js/bun/resolve/bun-main-entry-point.test.ts
index cccd5dcaf80..9cfea1c7e17 100644
--- a/test/js/bun/resolve/bun-main-entry-point.test.ts
+++ b/test/js/bun/resolve/bun-main-entry-point.test.ts
@@ -18,9 +18,16 @@ function stripAsanWarning(stderr: string): string[] {
 
 test.concurrent("dynamic import('bun:main') returns the wrapper module", async () => {
   using dir = tempDir("bun-main-dyn", {
+    // package.json disables auto-install so a regression in the bun:main alias
+    // cannot silently fall through to fetching the npm `main` package.
+    "package.json": "{}",
     "entry.mjs": `
       const m = await import("bun:main");
-      if (typeof m !== "object" || m === null) throw new Error("expected module namespace");
+      if (m[Symbol.toStringTag] !== "Module") throw new Error("expected module namespace, got " + Object.prototype.toString.call(m));
+      // The wrapper has no named exports. The npm \`main\` package (what this
+      // resolved to before the alias fix) exports {default,length,name,prototype}.
+      const keys = Object.keys(m);
+      if (keys.length !== 0) throw new Error("expected empty wrapper namespace, got keys: " + keys.join(","));
       console.log("OK");
     `,
   });
@@ -32,16 +39,20 @@ test.concurrent("dynamic import('bun:main') returns the wrapper module", async (
     stderr: "pipe",
   });
   const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
-  expect(stdout).toBe("OK\n");
-  expect(stripAsanWarning(stderr)).toEqual([]);
-  expect(exitCode).toBe(0);
+  expect({ stdout, stderr: stripAsanWarning(stderr), exitCode, signalCode: proc.signalCode }).toEqual({
+    stdout: "OK\n",
+    stderr: [],
+    exitCode: 0,
+    signalCode: null,
+  });
 });
 
 test.concurrent("import('bun:main') from a preload (before the module map is populated)", async () => {
   using dir = tempDir("bun-main-preload", {
+    "package.json": "{}",
     "preload.mjs": `
       const m = await import("bun:main");
-      if (typeof m !== "object" || m === null) throw new Error("expected module namespace");
+      if (m[Symbol.toStringTag] !== "Module") throw new Error("expected module namespace");
       console.log("PRELOAD_OK");
     `,
     "entry.mjs": `console.log("ENTRY_OK");`,
@@ -54,9 +65,14 @@ test.concurrent("import('bun:main') from a preload (before the module map is pop
     stderr: "pipe",
   });
   const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
-  expect(stdout).toBe("PRELOAD_OK\nENTRY_OK\n");
-  expect(stripAsanWarning(stderr)).toEqual([]);
-  expect(exitCode).toBe(0);
+  // import("bun:main") evaluates the wrapper, which evaluates entry.mjs, so
+  // ENTRY_OK prints before the preload's await resumes.
+  expect({ stdout, stderr: stripAsanWarning(stderr), exitCode, signalCode: proc.signalCode }).toEqual({
+    stdout: "ENTRY_OK\nPRELOAD_OK\n",
+    stderr: [],
+    exitCode: 0,
+    signalCode: null,
+  });
 });
 
 test.concurrent(