[philprime]

Adds a dedicated Flamegraph section to issue details when an event has a version-1 event.flamegraph attachment. It uses the existing attachment listing and download endpoints, with loading, explicit retry, and unsupported-format handling. The section is gated by event-attachments and flamegraph-attachments.

The viewer reuses the profiling canvas, theme, hover tooltips, and scrolling used by MetricKit flamegraphs without changing the existing MetricKit implementation. A separate adapter converts attachment nodes into weighted paths, preserving inclusive counts, samples ending at intermediate nodes, repeated frames, and recursion. Multiple attachments and call trees can be selected independently. Unclassified frames use the system-frame color.

Backend prerequisite: #126459. Land the backend first so the feature flag is exposed to the UI.

The 33 focused tests include the existing MetricKit and view-hierarchy suites. Full frontend typechecking and lint passed. Playwright verification against a local event attachment confirmed a painted canvas, independent tree counts, hover tooltips, scrolling, and collapse persistence. Diagnostic payloads and browser artifacts are not included.

[github-actions]

Story previews

Preview the stories changed in this PR on the Vercel deployment:

• app/components/events/flamegraphAttachment/flamegraphAttachment.stories.mdx

_{Preview deployment: https://sentry-b5afbxnmv.sentry.dev}

[github-actions]

📊 Type Coverage Diff

Metric	Before	After	Delta
Coverage	95.77%	95.77%	±0%
Typed	141,373	141,458	🟢 +85
Untyped	6,247	6,255	🔴 +8

🔍 8 new type safety issues introduced

Non-null assertions (!) (7 new)

File	Line	Detail
static/app/components/events/flamegraphAttachment/index.tsx	34	data.trees[selectedTree]!
static/app/components/events/flamegraphAttachment/utils.ts	56	data.nodes[id]!
static/app/components/events/flamegraphAttachment/utils.ts	69	pending.pop()!
static/app/components/events/flamegraphAttachment/utils.ts	83	data.nodes[current.id]!
static/app/components/events/flamegraphAttachment/utils.ts	126	data.nodes[id]!
static/app/components/events/flamegraphAttachment/utils.ts	131	data.nodes[child]!
static/app/components/events/flamegraphAttachment/utils.ts	137	children[index]!

Type assertions (as) (1 new)

File	Line	Detail
static/app/components/events/flamegraphAttachment/utils.ts	123	as number[] — [] as number[]

This is informational only and does not block the PR.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[linear-code]

COCOA-2071

[scttcper]

looks good!

[philprime]

@scttcper I slightly adapted the algorithm to reconstruct the tree due to changes in the (draft) file changes here: getsentry/sentry-docs#20073

No visual changes, tried it locally using https://sentry-sdks.sentry.io/issues/7738016221/events/8b04e1bf48504280842443da5575c9fb/ but disabling the feature flag check, as the flag has not been merged yet: https://github.com/getsentry/sentry-options-automator/pull/10184

[sentry]

Sentry Snapshot Testing

Name	Added	Removed	Changed	Renamed	Unchanged	Skipped	Status
sentry-frontend sentry-frontend	-	-	-	-	-	-	✅ 754 uploaded

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