ref(browser): Move trace lifecycle listeners to class function#18231

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ref(browser): Move trace lifecycle listeners to class function #18231

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138 changes: 68 additions & 70 deletions packages/browser/src/profiling/UIProfiler.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
this._client = client;
this._sessionSampled = sessionSampled;

client.on('spanStart', span => {
if (!this._sessionSampled) {
DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
return;
}
if (span !== getRootSpan(span)) {
return;
}
// Only count sampled root spans
if (!span.isRecording()) {
DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
return;
}

// Matching root spans with profiles
getGlobalScope().setContext('profile', {
profiler_id: this._profilerId,
});

const spanId = span.spanContext().spanId;
if (!spanId) {
return;
}
if (this._activeRootSpanIds.has(spanId)) {
return;
}

this._activeRootSpanIds.add(spanId);
const rootSpanCount = this._activeRootSpanIds.size;

const timeout = setTimeout(() => {
this._onRootSpanTimeout(spanId);
}, MAX_ROOT_SPAN_PROFILE_MS);
this._rootSpanTimeouts.set(spanId, timeout);

if (rootSpanCount === 1) {
DEBUG_BUILD &&
debug.log(
`[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
);

this.start();
}
});

client.on('spanEnd', span => {
if (!this._sessionSampled) {
return;
}

const spanId = span.spanContext().spanId;
if (!spanId || !this._activeRootSpanIds.has(spanId)) {
return;
}

this._activeRootSpanIds.delete(spanId);
const rootSpanCount = this._activeRootSpanIds.size;

DEBUG_BUILD &&
debug.log(
`[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
);
if (rootSpanCount === 0) {
this._collectCurrentChunk().catch(e => {
DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
});

this.stop();
}
});
this._setupTraceLifecycleListeners(client);
}

/**
Comment on lines 62 to 68

@sentrysentryBotNov 17, 2025

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95

🔍 Detailed Analysis

The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.

💡 Suggested Fix

Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.

🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.

Reference_id: 2726774

@s1gr1ds1gr1dNov 17, 2025•
edited
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This is done in another function - no problem here

It's kept track of it in _rootSpanTimeouts

Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

// Expose profiler_id to match root spans with profiles
getGlobalScope().setContext('profile', { profiler_id: this._profilerId });

@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift

Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.

Fix in CursorFix in Web

@s1gr1ds1gr1dNov 17, 2025

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Works as intended, this is still attached at the correct time.


this._startProfilerInstance();

if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
});
}

/** Trace-mode: attach spanStart/spanEnd listeners. */
private _setupTraceLifecycleListeners(client: Client): void {
client.on('spanStart', span => {
if (!this._sessionSampled) {
DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
return;
}
if (span !== getRootSpan(span)) {
return; // only care about root spans
}
// Only count sampled root spans
if (!span.isRecording()) {
DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
return;
}

const spanId = span.spanContext().spanId;
if (!spanId || this._activeRootSpanIds.has(spanId)) {
return;
}

this._registerTraceRootSpan(spanId);

const rootSpanCount = this._activeRootSpanIds.size;
if (rootSpanCount === 1) {
DEBUG_BUILD &&
debug.log(
`[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
);
this.start();
}
});

client.on('spanEnd', span => {
if (!this._sessionSampled) {
return;
}
const spanId = span.spanContext().spanId;
if (!spanId || !this._activeRootSpanIds.has(spanId)) {
return;
}
this._activeRootSpanIds.delete(spanId);
const rootSpanCount = this._activeRootSpanIds.size;

DEBUG_BUILD &&
debug.log(
`[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
);
if (rootSpanCount === 0) {
this._collectCurrentChunk().catch(e => {
DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
});
this.stop();
}
});
}

/**
* Resets profiling information from scope and resets running state
*/
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
this._rootSpanTimeouts.clear();
}

/** Register root span and schedule safeguard timeout (trace mode). */
private _registerTraceRootSpan(spanId: string): void {
this._activeRootSpanIds.add(spanId);
const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
this._rootSpanTimeouts.set(spanId, timeout);
}

/**
* Start a profiler instance if needed.
*/
Expand Down
Loading
, '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
ref(browser): Move trace lifecycle listeners to class function#18231

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 Merged

s1gr1d
merged 1 commit into

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Nov 17, 2025
 Merged


ref(browser): Move trace lifecycle listeners to class function
#18231
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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

Comment on lines

62
 to 
68

@sentrysentryBotNov 17, 2025

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
Loading

, '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
ref(browser): Move trace lifecycle listeners to class function#18231

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 Merged

s1gr1d
merged 1 commit into

from

Nov 17, 2025
 Merged


ref(browser): Move trace lifecycle listeners to class function
#18231
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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

Comment on lines

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68

@sentrysentryBotNov 17, 2025

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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MemberAuthor
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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
Loading

, '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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ref(browser): Move trace lifecycle listeners to class function#18231

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ref(browser): Move trace lifecycle listeners to class function
#18231
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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

Comment on lines

62
 to 
68

@sentrysentryBotNov 17, 2025

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
Loading

, '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" + '

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ref(browser): Move trace lifecycle listeners to class function#18231

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merged 1 commit into

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ref(browser): Move trace lifecycle listeners to class function
#18231
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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

Comment on lines

62
 to 
68

@sentrysentryBotNov 17, 2025

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
Loading

, '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
ref(browser): Move trace lifecycle listeners to class function#18231

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privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

s1gr1d
merged 1 commit into

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Nov 17, 2025
 Merged


ref(browser): Move trace lifecycle listeners to class function
#18231
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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
Loading

, '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('^' + ".*" + '

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ref(browser): Move trace lifecycle listeners to class function#18231

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ref(browser): Move trace lifecycle listeners to class function
#18231
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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
Loading

, '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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ref(browser): Move trace lifecycle listeners to class function#18231

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 Merged

s1gr1d
merged 1 commit into

from

Nov 17, 2025
 Merged


ref(browser): Move trace lifecycle listeners to class function
#18231
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Commits

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1 commit


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138 changes: 68 additions & 70 deletions
packages/browser/src/profiling/UIProfiler.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -62,76 +62,7 @@ export class UIProfiler {
 this._client = client;
 this._sessionSampled = sessionSampled;

 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return;
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 // Matching root spans with profiles
 getGlobalScope().setContext('profile', {
 profiler_id: this._profilerId,
 });

 const spanId = span.spanContext().spanId;
 if (!spanId) {
 return;
 }
 if (this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.add(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 const timeout = setTimeout(() => {
 this._onRootSpanTimeout(spanId);
 }, MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);

 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} started. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );

 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on `spanEnd`:', e);
 });

 this.stop();
 }
 });
 this._setupTraceLifecycleListeners(client);
 }

 /**

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68

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Bug:notifyRootSpanActive() fails to register a safeguard timeout for already-active root spans, leading to indefinite profiling if spanEnd is not called.
Severity: CRITICAL | Confidence: 0.95
🔍 Detailed Analysis
The notifyRootSpanActive() method, used for already-active root spans during profiler initialization, adds the span ID to _activeRootSpanIds but fails to call _registerTraceRootSpan(). This omission means no safeguard timeout is registered for these spans. If such a pre-existing root span never fires its spanEnd event, the profiler will continue running indefinitely, wasting resources by continuously collecting and sending profile chunks every 60 seconds, contradicting the intended design of MAX_ROOT_SPAN_PROFILE_MS.
💡 Suggested Fix
Modify notifyRootSpanActive() to call _registerTraceRootSpan(spanId) instead of directly adding spanId to _activeRootSpanIds. This ensures that all active root spans, regardless of how they are initialized, have the necessary safeguard timeout registered.
🤖 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/browser/src/profiling/UIProfiler.ts#L62-L68
Potential issue: The `notifyRootSpanActive()` method, used for already-active root spans
during profiler initialization, adds the span ID to `_activeRootSpanIds` but fails to
call `_registerTraceRootSpan()`. This omission means no safeguard timeout is registered
for these spans. If such a pre-existing root span never fires its `spanEnd` event, the
profiler will continue running indefinitely, wasting resources by continuously
collecting and sending profile chunks every 60 seconds, contradicting the intended
design of `MAX_ROOT_SPAN_PROFILE_MS`.

Did we get this right? 👍 / 👎 to inform future reviews.
Reference_id: 2726774
@s1gr1ds1gr1dNov 17, 2025•

edited

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This is done in another function - no problem here
It's kept track of it in _rootSpanTimeouts
Expand DownExpand Up@@ -170,6 +101,9 @@ export class UIProfiler {

 DEBUG_BUILD && debug.log('[Profiling] Started profiling with profile ID:', this._profilerId);

 // Expose profiler_id to match root spans with profiles
 getGlobalScope().setContext('profile', { profiler_id: this._profilerId });
@cursorcursorBotNov 17, 2025

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Bug: Profiler Context: Spans Adrift
Moving the global scope context setting from the spanStart listener to start() breaks profile-span association when the profiler fails to initialize. If the first root span fails to start the profiler, _resetProfilerInfo() clears the context and sets _isRunning to false. Subsequent root spans won't call start() (since rootSpanCount !== 1), leaving them without the profiler_id context needed to match spans with profiles.
Fix in CursorFix in Web
@s1gr1ds1gr1dNov 17, 2025

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MemberAuthor
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Works as intended, this is still attached at the correct time.

 this._startProfilerInstance();

 if (!this._profiler) {
Expand DownExpand Up@@ -203,6 +137,63 @@ export class UIProfiler {
 });
 }

 /** Trace-mode: attach spanStart/spanEnd listeners. */
 private _setupTraceLifecycleListeners(client: Client): void {
 client.on('spanStart', span => {
 if (!this._sessionSampled) {
 DEBUG_BUILD && debug.log('[Profiling] Session not sampled because of negative sampling decision.');
 return;
 }
 if (span !== getRootSpan(span)) {
 return; // only care about root spans
 }
 // Only count sampled root spans
 if (!span.isRecording()) {
 DEBUG_BUILD && debug.log('[Profiling] Discarding profile because root span was not sampled.');
 return;
 }

 const spanId = span.spanContext().spanId;
 if (!spanId || this._activeRootSpanIds.has(spanId)) {
 return;
 }

 this._registerTraceRootSpan(spanId);

 const rootSpanCount = this._activeRootSpanIds.size;
 if (rootSpanCount === 1) {
 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span ${spanId} started. Profiling active while there are active root spans (count=${rootSpanCount}).`,
 );
 this.start();
 }
 });

 client.on('spanEnd', span => {
 if (!this._sessionSampled) {
 return;
 }
 const spanId = span.spanContext().spanId;
 if (!spanId || !this._activeRootSpanIds.has(spanId)) {
 return;
 }
 this._activeRootSpanIds.delete(spanId);
 const rootSpanCount = this._activeRootSpanIds.size;

 DEBUG_BUILD &&
 debug.log(
 `[Profiling] Root span with ID ${spanId} ended. Will continue profiling for as long as there are active root spans (currently: ${rootSpanCount}).`,
 );
 if (rootSpanCount === 0) {
 this._collectCurrentChunk().catch(e => {
 DEBUG_BUILD && debug.error('[Profiling] Failed to collect current profile chunk on last `spanEnd`:', e);
 });
 this.stop();
 }
 });
 }

 /**
 * Resets profiling information from scope and resets running state
 */
Expand All@@ -219,6 +210,13 @@ export class UIProfiler {
 this._rootSpanTimeouts.clear();
 }

 /** Register root span and schedule safeguard timeout (trace mode). */
 private _registerTraceRootSpan(spanId: string): void {
 this._activeRootSpanIds.add(spanId);
 const timeout = setTimeout(() => this._onRootSpanTimeout(spanId), MAX_ROOT_SPAN_PROFILE_MS);
 this._rootSpanTimeouts.set(spanId, timeout);
 }

 /**
 * Start a profiler instance if needed.
 */
Expand Down
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