fix(core): Use WeakRef for Span-Scope circular references - #21242

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JPeer264 merged 4 commits into
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jp/memory-leak-traces-sample-rate
Jun 1, 2026
Merged

fix(core): Use WeakRef for Span-Scope circular references#21242
JPeer264 merged 4 commits into
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jp/memory-leak-traces-sample-rate

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@JPeer264JPeer264 commented May 29, 2026

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closes#18339
closes JS-1224

This PR adresses two problems:

Problem 1

The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.

Problem 2

When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.

A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339

Memory snapshots

Before

SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)

After

The memory clearly doesn't spike that much anymore

SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)

AI generated text:

Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.

Replace unbounded Map with LRUMap for _sentSpans in the span exporter to
prevent memory growth from accumulated span IDs.

@JPeer264
JPeer264 requested a review from a teamMay 29, 2026 09:41
@JPeer264JPeer264 self-assigned this May 29, 2026
@JPeer264
JPeer264 requested a review from a team as a code ownerMay 29, 2026 09:41
@JPeer264
JPeer264 requested review from andreiborza, logaretm and mydea and removed request for a teamMay 29, 2026 09:41
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JS-1224

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size-limit report 📦

PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺

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Comment threadpackages/core/src/utils/spanUtils.ts Outdated
Comment threadpackages/core/src/tracing/utils.ts Outdated
@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
@JPeer264
JPeer264force-pushed the jp/memory-leak-traces-sample-rate branch from c41e7c6 to e0af87fCompareMay 29, 2026 09:52
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Comment threadpackages/core/src/utils/spanUtils.ts
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Cursor Bugbot has reviewed your changes and found 1 potential issue.

Fix All in Cursor

❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.

Reviewed by Cursor Bugbot for commit 6619ea6. Configure here.

Comment threadpackages/core/src/utils/spanUtils.ts Outdated
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Comment threadpackages/core/src/utils/spanUtils.ts Outdated
@JPeer264
JPeer264force-pushed the jp/memory-leak-traces-sample-rate branch from 089ec80 to 5df54e7CompareMay 29, 2026 16:46
@JPeer264
JPeer264 merged commit a79f66e into developJun 1, 2026
265 of 267 checks passed
@JPeer264
JPeer264 deleted the jp/memory-leak-traces-sample-rate branch June 1, 2026 14:50
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@logaretmlogaretmlogaretm approved these changes
@sentrysentry[bot]sentry[bot] left review comments
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@mydeamydeaAwaiting requested review from mydeamydea is a code owner automatically assigned from getsentry/team-javascript-sdks-server
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Memory leak with high tracesSampleRate

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@JPeer264@mydea@logaretm
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
fix(core): Use WeakRef for Span-Scope circular references - #21242
Merged
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Jun 1, 2026
Merged
fix(core): Use WeakRef for Span-Scope circular references#21242
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Conversation
@JPeer264
@JPeer264JPeer264
commented
May 29, 2026

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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
@JPeer264
JPeer264
requested a review
from a teamMay 29, 2026 09:41
@JPeer264JPeer264
self-assigned this
May 29, 2026
@JPeer264
JPeer264
requested a review
from a team
as a code ownerMay 29, 2026 09:41
@JPeer264
JPeer264
requested review from
andreiborza, logaretm and mydea
and removed request for
a teamMay 29, 2026 09:41
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JS-1224
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
View base workflow run
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@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Cursor Bugbot has reviewed your changes and found 1 potential issue.
Fix All in Cursor
❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.
Reviewed by Cursor Bugbot for commit 6619ea6. Configure here.
Comment threadpackages/core/src/utils/spanUtils.ts
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265 of 267 checks passed

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Memory leak with high tracesSampleRate

3 participants

@JPeer264@mydea@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fix(core): Use WeakRef for Span-Scope circular references - #21242
Merged
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Jun 1, 2026
Merged
fix(core): Use WeakRef for Span-Scope circular references#21242
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Conversation
@JPeer264
@JPeer264JPeer264
commented
May 29, 2026

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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
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@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Cursor Bugbot has reviewed your changes and found 1 potential issue.
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❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.
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Memory leak with high tracesSampleRate

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@JPeer264@mydea@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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fix(core): Use WeakRef for Span-Scope circular references - #21242
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Merged
fix(core): Use WeakRef for Span-Scope circular references#21242
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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
@JPeer264
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@JPeer264JPeer264
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@JPeer264
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requested a review
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@JPeer264
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requested review from
andreiborza, logaretm and mydea
and removed request for
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
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Comment threadpackages/core/src/utils/spanUtils.ts
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@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
@JPeer264
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Cursor Bugbot has reviewed your changes and found 1 potential issue.
Fix All in Cursor
❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.
Reviewed by Cursor Bugbot for commit 6619ea6. Configure here.
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@JPeer264
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merged commit a79f66e
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265 of 267 checks passed

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Memory leak with high tracesSampleRate

3 participants

@JPeer264@mydea@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
fix(core): Use WeakRef for Span-Scope circular references - #21242
Merged
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Jun 1, 2026
Merged
fix(core): Use WeakRef for Span-Scope circular references#21242
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Conversation
@JPeer264
@JPeer264JPeer264
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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
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@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Cursor Bugbot has reviewed your changes and found 1 potential issue.
Fix All in Cursor
❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.
Reviewed by Cursor Bugbot for commit 6619ea6. Configure here.
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Memory leak with high tracesSampleRate

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@JPeer264@mydea@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fix(core): Use WeakRef for Span-Scope circular references - #21242
Merged
JPeer264 merged 4 commits into
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jp/memory-leak-traces-sample-rate
Jun 1, 2026
Merged
fix(core): Use WeakRef for Span-Scope circular references#21242
JPeer264 merged 4 commits into
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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
@JPeer264
JPeer264
requested a review
from a teamMay 29, 2026 09:41
@JPeer264JPeer264
self-assigned this
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@JPeer264
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requested a review
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as a code ownerMay 29, 2026 09:41
@JPeer264
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requested review from
andreiborza, logaretm and mydea
and removed request for
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
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Comment threadpackages/core/src/utils/spanUtils.ts
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@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
@JPeer264
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Cursor Bugbot has reviewed your changes and found 1 potential issue.
Fix All in Cursor
❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.
Reviewed by Cursor Bugbot for commit 6619ea6. Configure here.
Comment threadpackages/core/src/utils/spanUtils.ts
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@mydeamydeaAwaiting requested review from mydeamydea is a code owner automatically assigned from getsentry/team-javascript-sdks-server
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Successfully merging this pull request may close these issues.

Memory leak with high tracesSampleRate

3 participants

@JPeer264@mydea@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fix(core): Use WeakRef for Span-Scope circular references - #21242
Merged
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Jun 1, 2026
Merged
fix(core): Use WeakRef for Span-Scope circular references#21242
JPeer264 merged 4 commits into
developfrom 
jp/memory-leak-traces-sample-rate
Conversation
@JPeer264
@JPeer264JPeer264
commented
May 29, 2026

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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
@JPeer264
JPeer264
requested a review
from a teamMay 29, 2026 09:41
@JPeer264JPeer264
self-assigned this
May 29, 2026
@JPeer264
JPeer264
requested a review
from a team
as a code ownerMay 29, 2026 09:41
@JPeer264
JPeer264
requested review from
andreiborza, logaretm and mydea
and removed request for
a teamMay 29, 2026 09:41
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
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fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Memory leak with high tracesSampleRate

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@JPeer264@mydea@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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fix(core): Use WeakRef for Span-Scope circular references - #21242
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jp/memory-leak-traces-sample-rate
Jun 1, 2026
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fix(core): Use WeakRef for Span-Scope circular references#21242
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closes#18339

closes JS-1224
This PR adresses two problems:
Problem 1
The _sentryScope has a reference on the span and the span has a reference to the scope, which is a circular dependency and it couldn't be garbage collected.
Problem 2
When a span has been sent, they are kept for 5 minutes as cache just in case, which could eat up memory quite fast, but is actively removed after 5 minutes. By changing this to an LRUMap, we can still keep them, but limit them to 10k spans.
A reproduction and load tests can be found here: https://github.com/JPeer264/sentry-repros/tree/issue-18339
Memory snapshots
Before
SnapshotTimeHeap SizeNode Count
Baseline0:0023.6 MB207,767
During 11:4744.9 MB (+90%)585,619 (+182%)
During 23:4871.1 MB (+201%)1,192,498 (+474%)
During 35:50100.9 MB (+327%)1,794,671 (+764%)
During 47:50105.6 MB (+347%)2,019,638 (+872%)
During 59:51133.7 MB (+466%)2,020,743 (+873%)
During 611:51134.0 MB (+467%)2,023,947 (+874%)
Final13:15120.1 MB (+409%)1,734,738 (+735%)
After
The memory clearly doesn't spike that much anymore
SnapshotTimeHeap SizeNode Count
Baseline0:0019.2 MB186,001
During 13:2425.4 MB (+32%)236,693 (+27%)
During 26:2525.7 MB (+34%)240,009 (+29%)
During 39:2526.0 MB (+35%)243,060 (+31%)
During 412:2525.8 MB (+34%)237,430 (+28%)
Final12:5124.7 MB (+29%)220,281 (+18%)
AI generated text:
Break the circular reference between Span and Scope by using WeakRef

in both directions, allowing proper garbage collection of completed

spans and their associated scopes.
Replace unbounded Map with LRUMap for _sentSpans in the span exporter to

prevent memory growth from accumulated span IDs.
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JS-1224
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser27.2 kB+0.14%+37 B 🔺
@sentry/browser - with treeshaking flags25.65 kB+0.13%+33 B 🔺
@sentry/browser (incl. Tracing)45.25 kB--
@sentry/browser (incl. Tracing + Span Streaming)47.48 kB+0.01%+4 B 🔺
@sentry/browser (incl. Tracing, Profiling)50.24 kB+0.04%+18 B 🔺
@sentry/browser (incl. Tracing, Replay)84.84 kB+0.02%+12 B 🔺
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags74.4 kB+0.01%+7 B 🔺
@sentry/browser (incl. Tracing, Replay with Canvas)89.54 kB+0.02%+13 B 🔺
@sentry/browser (incl. Tracing, Replay, Feedback)102.16 kB+0.01%+9 B 🔺
@sentry/browser (incl. Feedback)44.36 kB+0.06%+24 B 🔺
@sentry/browser (incl. sendFeedback)32.02 kB+0.12%+36 B 🔺
@sentry/browser (incl. FeedbackAsync)37.11 kB+0.09%+32 B 🔺
@sentry/browser (incl. Metrics)28.27 kB+0.1%+27 B 🔺
@sentry/browser (incl. Logs)28.52 kB+0.11%+31 B 🔺
@sentry/browser (incl. Metrics & Logs)29.22 kB+0.11%+32 B 🔺
@sentry/react29.03 kB+0.13%+36 B 🔺
@sentry/react (incl. Tracing)47.52 kB+0.03%+14 B 🔺
@sentry/vue32.22 kB+0.05%+13 B 🔺
@sentry/vue (incl. Tracing)47.16 kB+0.01%+1 B 🔺
@sentry/svelte27.23 kB+0.14%+37 B 🔺
CDN Bundle29.58 kB+0.09%+26 B 🔺
CDN Bundle (incl. Tracing)47.81 kB+0.01%+3 B 🔺
CDN Bundle (incl. Logs, Metrics)31.08 kB+0.11%+34 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics)49.05 kB+0.03%+13 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics)70.34 kB+0.05%+29 B 🔺
CDN Bundle (incl. Tracing, Replay)85.18 kB+0.01%+1 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)86.35 kB+0.01%+4 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback)91.05 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)92.2 kB-0.01%-7 B 🔽
CDN Bundle - uncompressed87.69 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing) - uncompressed144.1 kB+0.01%+8 B 🔺
CDN Bundle (incl. Logs, Metrics) - uncompressed92.18 kB+0.11%+96 B 🔺
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed147.86 kB+0.01%+8 B 🔺
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed216.9 kB+0.05%+96 B 🔺
CDN Bundle (incl. Tracing, Replay) - uncompressed262.88 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed266.62 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed276.57 kB+0.01%+8 B 🔺
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed280.31 kB+0.01%+8 B 🔺
@sentry/nextjs (client)50.05 kB+0.05%+21 B 🔺
@sentry/sveltekit (client)45.7 kB+0.06%+25 B 🔺
@sentry/core/server75.94 kB-0.82%-621 B 🔽
@sentry/core/browser63.09 kB-0.01%-1 B 🔽
@sentry/node-core61.7 kB+0.02%+10 B 🔺
@sentry/node130.35 kB-0.13%-159 B 🔽
@sentry/node - without tracing74.06 kB-0.05%-31 B 🔽
@sentry/aws-serverless86.26 kB-0.04%-27 B 🔽
@sentry/cloudflare (withSentry) - minified171.5 kB+0.01%+8 B 🔺
@sentry/cloudflare (withSentry)429.32 kB+0.01%+27 B 🔺
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@JPeer264@claude
fix(core): Use WeakRef for Span-Scope circular references
e0af87f
Break the circular reference between Span and Scope by using WeakRef
in both directions, allowing proper garbage collection of completed
spans and their associated scopes.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Cursor Bugbot has reviewed your changes and found 1 potential issue.
Fix All in Cursor
❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.
Reviewed by Cursor Bugbot for commit 6619ea6. Configure here.
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Memory leak with high tracesSampleRate

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