fix(bun): Keep diagnostics channel subscriptions alive

[JPeer264]

Bun garbage-collects a diagnostics channel that no code references, and its subscribers with it. Node and Deno keep subscribed channels alive. The channel integrations kept no reference, so on Bun they could silently stop producing spans after the first GC. They now create their channels through wrappers in @sentry/server-utils that keep one.

@sentry/bun uses these integrations, and also httpIntegration from @sentry/node, whose channel subscriptions now go through the same wrappers. diagnosticsChannelGc.test.ts reproduces the GC on Bun.

Running the shared Node integration suites on Bun found this. Also an oxlint rule has been added to prevent any issues in the future regarding this

Part of #23889.

🤖 Generated with Claude Code

[linear-code]

JS-3515

[github-actions]

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	29.24 kB	-	-
@sentry/browser - with treeshaking flags	27.5 kB	-	-
@sentry/browser - with treeshaking flags tracing without tracing	27.4 kB	-	-
@sentry/browser (incl. Tracing)	51.15 kB	-	-
@sentry/browser (incl. Tracing + Span Streaming)	51.17 kB	-	-
@sentry/browser (incl. Tracing, Profiling)	54.18 kB	-	-
@sentry/browser (incl. Tracing, Replay)	90.76 kB	-	-
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	79.86 kB	-	-
@sentry/browser (incl. Tracing, Replay with Canvas)	95.46 kB	-	-
@sentry/browser (incl. Tracing, Replay, Feedback)	108.41 kB	-	-
@sentry/browser (incl. Feedback)	46.76 kB	-	-
@sentry/browser (incl. sendFeedback)	34.3 kB	-	-
@sentry/browser (incl. FeedbackAsync)	39.41 kB	-	-
@sentry/browser (incl. Metrics)	30.25 kB	-	-
@sentry/browser (incl. Logs)	30.51 kB	-	-
@sentry/browser (incl. Metrics & Logs)	31.18 kB	-	-
@sentry/react	31 kB	-	-
@sentry/react (incl. Tracing)	53.45 kB	-	-
@sentry/vue	36.74 kB	-	-
@sentry/vue (incl. Tracing)	53.7 kB	-	-
@sentry/svelte	29.26 kB	-	-
CDN Bundle	30.93 kB	-	-
CDN Bundle (incl. Tracing)	51.69 kB	-	-
CDN Bundle (incl. Logs, Metrics)	33.2 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics)	53.66 kB	-	-
CDN Bundle (incl. Replay, Logs, Metrics)	73.92 kB	-	-
CDN Bundle (incl. Tracing, Replay)	89.28 kB	-	-
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)	91.25 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback)	95.45 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)	97.42 kB	-	-
CDN Bundle - uncompressed	91.4 kB	-	-
CDN Bundle (incl. Tracing) - uncompressed	153.77 kB	-	-
CDN Bundle (incl. Logs, Metrics) - uncompressed	97.97 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed	159.73 kB	-	-
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed	227.54 kB	-	-
CDN Bundle (incl. Tracing, Replay) - uncompressed	273.5 kB	-	-
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed	279.44 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	287.2 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed	293.13 kB	-	-
@sentry/nextjs (client)	55.77 kB	-	-
@sentry/sveltekit (client)	51.59 kB	-	-
@sentry/core/server	39.95 kB	-	-
@sentry/core/browser	13.63 kB	-	-
@sentry/node	137.15 kB	+0.03%	+37 B 🔺
@sentry/node/import (ESM hook with diagnostics-channel injection)	82.8 kB	-	-
@sentry/node - without tracing	90.81 kB	+0.1%	+89 B 🔺
@sentry/node - without channel injection	115.51 kB	+0.02%	+12 B 🔺
@sentry/aws-serverless	99.08 kB	+0.1%	+92 B 🔺
@sentry/cloudflare (withSentry) - minified	206.62 kB	-	-
@sentry/cloudflare (withSentry)	514.02 kB	-	-

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[JPeer264]

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[sentry]

Bug: The Bun-specific implementation of subscribe returns undefined, but its type annotation incorrectly claims it matches nodeDiagnosticsChannel.subscribe, which should return a subscription object.
_{Severity: LOW}

Suggested Fix

Modify the Bun-specific implementation of the subscribe function to return the result of channel(name).subscribe(onMessage). This will align the function's behavior with its type annotation and the standard Node.js implementation, ensuring it correctly returns a subscription object.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: packages/server-utils/src/utils/diagnosticsChannel.ts#L28-L32

Potential issue: The `subscribe` function in `diagnosticsChannel.ts` has a conditional
implementation for Bun environments. This implementation does not return a value,
resulting in an `undefined` return. However, the function is typed as `typeof
nodeDiagnosticsChannel.subscribe`, which implies it should return a subscription object
with an `unsubscribe()` method. While no current call sites in the codebase utilize this
return value, this type discrepancy could lead to runtime errors in the future if the
function is used in a context that expects a subscription object to be returned.