[@sentry/bun] NodeClient always overrides runtime context to 'node', ignoring Bun SDK's runtime option

[BYK]

Problem

In @sentry/bun v10, the Bun SDK's init() correctly sets runtime: { name: 'bun', version: Bun.version } on the options object, but then delegates to @sentry/node's init(), which creates a NodeClient. The NodeClient constructor always overrides the runtime:

// @sentry/node-core/build/esm/sdk/client.js, NodeClient constructor
const clientOptions = {
 ...options, // ← spreads bun's runtime: { name: 'bun', version: '1.x.x' }
 platform: 'node',
 runtime: { name: 'node', version: global.process.version }, // ← OVERRIDES it
 serverName,
};

Because runtime comes after ...options in the object literal, the Bun SDK's runtime is always overridden with { name: 'node' }.

Under Bun, global.process.version returns the Node.js compatibility version (e.g., v24.3.0), not the actual Bun version. This means:

• event.contexts.runtime incorrectly shows { name: 'node', version: 'v24.3.0' } for events sent from Bun
• Sentry's server-side tag promotion creates a runtime tag with value node instead of bun

Expected Behavior

When using @sentry/bun, event.contexts.runtime should be { name: 'bun', version: '<actual bun version>' }, and the server-side promoted runtime tag should show bun.

Reproduction

import * as Sentry from "@sentry/bun";

const client = Sentry.init({ dsn: "..." });
console.log(client?.getOptions().runtime);
// Actual: { name: 'node', version: 'v24.3.0' }
// Expected: { name: 'bun', version: '1.3.8' }

Context

This was BunClient's job (it correctly set runtime: { name: 'bun' }), but BunClient was deprecated in v9/v10 and the Bun SDK now delegates entirely to @sentry/node's init() → NodeClient.

Suggested Fix

In NodeClient's constructor, respect the runtime option if it was already set by a wrapping SDK:

const clientOptions = {
 ...options,
 platform: 'node',
 runtime: options.runtime || { name: 'node', version: global.process.version },
 serverName,
};

Or alternatively, in @sentry/bun's init(), override the runtime after NodeClient is created:

const client = init$1(options);
if (client) {
 client.getOptions().runtime = { name: 'bun', version: Bun.version };
}
return client;

Workaround

We're currently working around this by mutating client.getOptions().runtime after Sentry.init():

const client = Sentry.init({ ... });
if (client && typeof process.versions.bun !== "undefined") {
 (client.getOptions() as any).runtime = {
 name: "bun",
 version: process.versions.bun,
 };
}

Versions

• @sentry/bun: 10.38.0
• @sentry/node: 10.38.0
• @sentry/core: 10.38.0
• Bun: 1.3.8

[linear]

JS-1682

[timfish]

Looks like this might be the case for Deno too?

sentry-javascript/packages/deno/src/client.ts

Lines 39 to 46 in 8dd90ae

	const clientOptions: ServerRuntimeClientOptions = {
	...options,
	platform: 'javascript',
	runtime: { name: 'deno', version: Deno.version.deno },
	serverName: options.serverName || getHostName(),
	};
	super(clientOptions);

[nicohrubec]

This should already be resolved. The fix will ship with the next release!