feat(core,cli,supervisor): bun-1.4 runtime (node-less, Bun 1.4.4) plus a bun-legacy alias

Adds the `bun-1.4` runtime. `runtime: "bun-1.4"` deploys on Bun 1.4.4 in
a Bun-only image with no Node.js binary, and the run controller itself
runs under Bun. `runtime: "bun"` keeps today's behavior (Bun 1.3.3 with
Node.js 20 alongside it); `bun-legacy` is accepted as an explicit
spelling of the same runtime.

Bun 1.4 rejects the `--no-warnings=ExperimentalWarning` flag the worker
was started with, so bun workers now get the bare `--no-warnings` form.
The supervisor, build plugins, and rsc extension recognise every bun
runtime instead of only the plain `bun` value.

Docs cover the runtimes, that the `bun-1.4` image contains no Node.js
binary, and the open Bun 1.4 `node:http2` client regression.

Mono-RevId: 29aae0f8cb56dfb912865e00b72169d26b12aaf7

Author: ericallam

.changeset/versioned-bun-runtimes.md

@@ -0,0 +1,7 @@
+---
+"trigger.dev": patch
+"@trigger.dev/core": patch
+"@trigger.dev/rsc": patch
+---
+
+Adds the `bun-1.4` runtime. `runtime: "bun-1.4"` deploys on Bun 1.4.4 in a Bun-only image with no Node.js binary, and the run controller itself runs under Bun. `runtime: "bun"` is unchanged (Bun 1.3 with Node.js alongside it); `bun-legacy` is accepted as an explicit spelling of the same runtime. On Bun 1.4 the worker no longer crashes at startup on the `--no-warnings=ExperimentalWarning` flag.

apps/supervisor/src/workloadManager/kubernetes.test.ts

@@ -222,8 +222,10 @@ describe("runnerSecurityContext", () => {
     });
   });
 
-  it("pins bun's own uid, which differs from node's", () => {
-    expect(runnerSecurityContext("restricted", 1000, "bun")?.runAsUser).toBe(1001);
+  it("pins bun's own uid, which differs from node's, for every bun runtime", () => {
+    for (const runtime of ["bun", "bun-legacy", "bun-1.4"]) {
+      expect(runnerSecurityContext("restricted", 1000, runtime)?.runAsUser).toBe(1001);
+    }
   });
 
   it("falls back to the configured uid when the runtime is unknown", () => {

apps/supervisor/src/workloadManager/kubernetesPodSpec.ts

@@ -1,4 +1,5 @@
 import type { k8s } from "../clients/kubernetes.js";
+import { isBunRuntime } from "@trigger.dev/core/v3/build";
 
 /**
  * An empty label is the documented off-switch, leaving the pod unpinned. The Helm
@@ -146,7 +147,7 @@ export function runnerSecurityContext(
     allowPrivilegeEscalation: false,
     capabilities: { drop: ["ALL"] },
     ...(level === "restricted"
-      ? { runAsNonRoot: true, runAsUser: runtime === "bun" ? BUN_RUN_AS_USER : runAsUser }
+      ? { runAsNonRoot: true, runAsUser: isBunRuntime(runtime) ? BUN_RUN_AS_USER : runAsUser }
       : {}),
   };
 }

docs/config/config-file.mdx

@@ -329,7 +329,7 @@ After each call we restore the few attributes we use to link a span to its run,
 
 If you don't set a `runtime`, your tasks run on the current Node.js LTS. Setting `runtime: "node"` does the same thing — see the Node.js versions section below to pin a specific version instead.
 
-We currently only officially support the `node` runtime, but you can try our experimental `bun` runtime by setting the `runtime` option in your config file:
+We currently only officially support the `node` runtime, but you can try our experimental Bun runtimes by setting the `runtime` option in your config file:
 
 ```ts trigger.config.ts
 import { defineConfig } from "@trigger.dev/sdk";
@@ -341,7 +341,7 @@ export default defineConfig({
 });
 ```
 
-See our [Bun guide](/guides/frameworks/bun) for more information.
+`bun` runs on Bun 1.3 with a Node.js binary alongside it. `bun-1.4` runs on a Bun-only image with no Node.js binary. See our [Bun guide](/guides/frameworks/bun) for the differences.
 
 ### Node.js versions
 

docs/guides/frameworks/bun.mdx

@@ -15,8 +15,26 @@ import CliViewRunStep from "/snippets/step-view-run.mdx";
 </Warning>
 
 <Note>
-  **Supported Bun version:** Deployed tasks run on Bun 1.3.3. For local development, use Bun 1.3.x
-  for compatibility.
+  **Supported Bun versions:** `runtime: "bun"` deploys on Bun 1.3.3 with a Node.js 20 binary
+  alongside it. Opt in to `runtime: "bun-1.4"` (Bun 1.4.4) for a
+  Bun-only image. For local development, match the Bun minor you deploy on.
+</Note>
+
+## Choosing a Bun runtime
+
+| `runtime`    | Bun    | Node.js binary in the image | Notes                                                                    |
+| ------------ | ------ | --------------------------- | ------------------------------------------------------------------------ |
+| `bun`        | 1.3.3  | Yes (Node.js 20)            | The default, also spelled `bun-legacy`. Use this if a task shells out to `node`. |
+| `bun-1.4`    | 1.4.4  | No                          | Bun-only image. See the Bun 1.4 note below.                              |
+
+The `bun-1.4` image contains **no Node.js binary**. Anything in your task that spawns
+`node` (a CLI tool, a `postinstall` script, a library that shells out) will fail on it. Keep those
+projects on `bun`, or install Node.js yourself with a build extension.
+
+<Note>
+  **Bun 1.4:** Bun 1.4.x has an open regression in its `node:http2` client
+  ([oven-sh/bun#39796](https://github.com/oven-sh/bun/issues/39796)). If your tasks use HTTP/2
+  clients, for example some gRPC or Google Cloud SDKs, use `bun` until it is fixed.
 </Note>
 
 <Prerequisites framework="Bun" />

docs/snippets/node-versions.mdx

@@ -4,15 +4,16 @@ Trigger.dev runs your deployed tasks on one of these runtimes:
 - Node.js `node-22` — `22.23.4`
 - Node.js `node-24` — `24.22.1`
 - Node.js `node-26` — `26.12.1`
-- Bun `bun` — `1.3.3`
+- Bun `bun` — `1.3.3` with Node.js `20` alongside it (also spelled `bun-legacy`)
+- Bun `bun-1.4` — `1.4.4`, no Node.js binary
 
 If you don't set a `runtime`, or you set `runtime: "node"`, your tasks run on the current Node.js LTS. That version moves forward as new LTS releases land, so set an explicit version — for example `runtime: "node-24"` — if you need it to stay fixed.
 
 ```ts
 import { defineConfig } from "@trigger.dev/sdk";
 
 export default defineConfig({
-  // "node", "node-22", "node-24", "node-26" or "bun"
+  // "node", "node-22", "node-24", "node-26", "bun" or "bun-1.4"
   runtime: "node-24",
   project: "<your-project-ref>",
 });

packages/cli-v3/src/build/plugins.ts

@@ -1,6 +1,6 @@
 import * as esbuild from "esbuild";
 import { BuildTarget } from "@trigger.dev/core/v3/schemas";
-import { ResolvedConfig } from "@trigger.dev/core/v3/build";
+import { isBunRuntime, ResolvedConfig } from "@trigger.dev/core/v3/build";
 import { configPlugin } from "../config.js";
 import { logger } from "../utilities/logger.js";
 import { bunPlugin } from "../runtimes/bun.js";
@@ -25,7 +25,7 @@ export async function buildPlugins(
 
   plugins.push(polyshedPlugin());
 
-  if (resolvedConfig.runtime === "bun") {
+  if (isBunRuntime(resolvedConfig.runtime)) {
     plugins.push(bunPlugin());
   }
 

packages/cli-v3/src/commands/init.ts

@@ -102,7 +102,7 @@ Examples:
       )
       .option(
         "-r, --runtime <runtime>",
-        "Which runtime to use for the project. Supported: node, node-22, node-24, node-26, bun",
+        "Which runtime to use for the project. Supported: node, node-22, node-24, node-26, bun, bun-1.4",
         "node-24"
       )
       .option("--skip-package-install", "Skip installing the @trigger.dev/sdk package")

packages/cli-v3/src/config.ts

@@ -7,6 +7,7 @@ import type {
 } from "@trigger.dev/core/v3";
 import type { ResolvedConfig } from "@trigger.dev/core/v3/build";
 import {
+  isBunRuntime,
   DEFAULT_RUNTIME,
   deprecatedRuntimeReplacement,
   isDeprecatedConfigRuntime,
@@ -367,10 +368,10 @@ function validateConfig(config: TriggerConfig, warn = true) {
     );
   }
 
-  if (config.runtime && config.runtime === "bun") {
+  if (isBunRuntime(config.runtime)) {
     warn &&
       prettyWarning(
-        `The "bun" runtime is currently experimental, and certain features may not work, especially opentelemetry instrumentation of 3rd party packages.`
+        `The "${config.runtime}" runtime is currently experimental, and certain features may not work, especially opentelemetry instrumentation of 3rd party packages.`
       );
   }
 }

packages/cli-v3/src/deploy/buildImage.test.ts

@@ -51,8 +51,18 @@ const images: Array<[BuildRuntime, string, string]> = [
   ],
   [
     "bun",
-    "triggerdotdev/bun:1.3-node20-bookworm@sha256:25b467196277b9d75a37773ee36d28b65ca81a6f41786f7d7d7f1fad95fb5a31",
-    "triggerdotdev/bun:1.3-node20-bookworm-build@sha256:a2d5e6d1ec25946ca1d86abdd9ffb9c589376df64ee1b490c461607953931245",
+    "triggerdotdev/bun:1.3-node20-bookworm@sha256:445d326788a0ba252e93c3923546fc06c44a5c303a0f476821f3f677864e160f",
+    "triggerdotdev/bun:1.3-node20-bookworm-build@sha256:3fbcebfc0eb098f70d7b3d29e81b26f59ef1c21887703b85621e9cfe50ab7bce",
+  ],
+  [
+    "bun-legacy",
+    "triggerdotdev/bun:1.3-node20-bookworm@sha256:445d326788a0ba252e93c3923546fc06c44a5c303a0f476821f3f677864e160f",
+    "triggerdotdev/bun:1.3-node20-bookworm-build@sha256:3fbcebfc0eb098f70d7b3d29e81b26f59ef1c21887703b85621e9cfe50ab7bce",
+  ],
+  [
+    "bun-1.4",
+    "triggerdotdev/bun:1.4-bookworm@sha256:91c471435cbf097e2301f17ec456cc398dc9ce9161d2317f4bbbd9cdae73a86e",
+    "triggerdotdev/bun:1.4-bookworm-build@sha256:9b16175d5bd65d036beae9f04518c0b6c8327aa5d7855002188899fb6f9a7376",
   ],
 ];
 
@@ -87,6 +97,55 @@ describe("generateContainerfile", () => {
     }
   );
 
+  it.each(["bun", "bun-legacy", "bun-1.4"] as BuildRuntime[])(
+    "builds %s on a bun image with the bun user",
+    async (runtime) => {
+      const containerfile = await generateContainerfile({
+        runtime,
+        build: {},
+        image: undefined,
+        indexScript: "index.js",
+        entrypoint: "entrypoint.js",
+      });
+
+      expect(containerfile).toContain(`FROM ${BASE_IMAGE[runtime]} AS base`);
+      expect(containerfile).toContain("USER bun");
+      expect(containerfile).toContain("RUN bun install --production --no-save");
+      expect(containerfile).toContain(`RUN [ "bun", "run", "index.js" ]`);
+    }
+  );
+
+  it.each(["bun", "bun-legacy"] as BuildRuntime[])(
+    "keeps the run controller on node for the %s node + bun image",
+    async (runtime) => {
+      const containerfile = await generateContainerfile({
+        runtime,
+        build: {},
+        image: undefined,
+        indexScript: "index.js",
+        entrypoint: "entrypoint.js",
+      });
+
+      expect(containerfile).toContain(`ENTRYPOINT [ "dumb-init", "node", "entrypoint.js" ]`);
+    }
+  );
+
+  it.each(["bun-1.4"] as BuildRuntime[])(
+    "runs the run controller under bun on the node-less %s image",
+    async (runtime) => {
+      const containerfile = await generateContainerfile({
+        runtime,
+        build: {},
+        image: undefined,
+        indexScript: "index.js",
+        entrypoint: "entrypoint.js",
+      });
+
+      expect(containerfile).toContain(`ENTRYPOINT [ "dumb-init", "bun", "entrypoint.js" ]`);
+      expect(containerfile).not.toContain(`"dumb-init", "node"`);
+    }
+  );
+
   it.each(["node", "bun"] as BuildRuntime[])(
     "runs no package installation for uncustomized projects on %s",
     async (runtime) => {
@@ -353,7 +412,7 @@ describe("generateContainerfile", () => {
     expect(repair).toBeGreaterThan(instructions);
   });
 
-  it.each(["node", "bun"] as BuildRuntime[])(
+  it.each(["node", "bun-legacy", "bun-1.4"] as BuildRuntime[])(
     "splits node_modules and app code into separate layers for %s",
     async (runtime) => {
       const containerfile = await generateContainerfile({
@@ -364,7 +423,7 @@ describe("generateContainerfile", () => {
         entrypoint: "entrypoint.js",
       });
 
-      const user = runtime === "bun" ? "bun:bun" : "node:node";
+      const user = runtime.startsWith("bun") ? "bun:bun" : "node:node";
 
       expect(containerfile).toContain("FROM scratch AS code");
       expect(containerfile).toContain("COPY --from=build --exclude=node_modules /app /app");
@@ -377,7 +436,7 @@ describe("generateContainerfile", () => {
     }
   );
 
-  it.each(["node", "bun"] as BuildRuntime[])(
+  it.each(["node", "bun-legacy"] as BuildRuntime[])(
     "orders post-install commands, the node_modules guard, and the code stage for %s",
     async (runtime) => {
       const containerfile = await generateContainerfile({