Display traced values in Stack Chart view by squarewave · Pull Request #5363 · firefox-devtools/profiler

squarewave · 2025-02-07T23:48:00Z

This is a rough draft of adding in the support for displaying traced values (from the JS Execution Tracing option) in the Stack Chart view. This currently requires the work in https://phabricator.services.mozilla.com/D236936 to function.

ochameau · 2025-03-14T08:35:15Z

@squarewave note that this is crashing on chrome

ErrorBoundary.js:43 An unhandled error was thrown in a React component. TypeError: First argument to DataView constructor must be an ArrayBuffer
    at new DataView (<anonymous>)
    at new Eu (value-summaries.js:49:18)
    at value-summaries.js:319:16

canova

Thanks for the PR! It looks like it's mostly working well! I have a few questions below, but my main concern is the crashes/exceptions I was getting when I was trying the deploy preview.

I changed the devtools.performance.recording.ui-base-url pref to "https://deploy-preview-5363--perf-html.netlify.app" and started capturing some example profiles with the JS tracer enabled. While hovering over some of the sampples in stack chart, I've encountered these crashes:

An unhandled error was thrown in a React component. Error: Bad object kind
    MC value-summaries.js:423
    FC value-summaries.js:476
    NC value-summaries.js:257
    MC value-summaries.js:410
    FC value-summaries.js:476
    RC value-summaries.js:495
    _getHoveredStackInfo Canvas.js:616
    _getHoveredItemInfo Canvas.js:342
    render Canvas.js:398
    React 8
    w scheduler.production.min.js:13
    _ scheduler.production.min.js:14
    7463 scheduler.production.min.js:14
    Webpack 13
 
rC@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:120:47154
qE@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:120:129223
div
t@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:120:36629
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
div
aA@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:43084
iA@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:45644
div
tk@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:123:481
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
fg@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:20380
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$e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:223805
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Gx@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:132:49519
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
s@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:46805
div
e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:48453
component@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:132:51659
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
s@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:46805
div
e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:48453
div
s@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:46805
div
e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:48453
div
div
JT@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:139:26671
BP@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:117837
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
CM@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:150225
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
ef@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:3169
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
MP@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:119982
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
fg@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:20380
Ag
$e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:223805
Ve@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:223718
ZM@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:170476
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
jt@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:229088
fg@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:20380
gg
eF@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:171580 ErrorBoundary.js:43:13
    componentDidCatch ErrorBoundary.js:43
    React 8
    w scheduler.production.min.js:13
    _ scheduler.production.min.js:14
    (Async: EventHandlerNonNull)
    7463 scheduler.production.min.js:14
    Webpack 13

And I got this:

An unhandled error was thrown in a React component. Error: Bad value type
    FC value-summaries.js:479
    NC value-summaries.js:257
    MC value-summaries.js:410
    FC value-summaries.js:476
    RC value-summaries.js:495
    _getHoveredStackInfo Canvas.js:616
    _getHoveredItemInfo Canvas.js:342
    render Canvas.js:398
    React 8
    w scheduler.production.min.js:13
    _ scheduler.production.min.js:14
 
rC@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:120:47154
qE@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:120:129223
div
t@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:120:36629
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
div
aA@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:43084
iA@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:45644
div
tk@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:123:481
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
fg@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:20380
Ag
$e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:223805
div
Gx@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:132:49519
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
s@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:46805
div
e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:48453
component@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:132:51659
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
s@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:46805
div
e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:48453
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s@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:46805
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e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:207:48453
div
div
JT@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:139:26671
BP@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:117837
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
CM@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:150225
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
ef@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:3169
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
div
MP@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:119982
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
fg@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:20380
Ag
$e@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:223805
Ve@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:223718
ZM@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:170476
c@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:230673
jt@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:2:229088
fg@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:117:20380
gg
eF@https://deploy-preview-5363--perf-html.netlify.app/main.2fcff16d608871ec81f3.bundle.js:143:171580 ErrorBoundary.js:43:13

So it looks like we get both bad object and value types somehow. We should fix these issues before landing, but I also have a few questions:

Are we expected to have unknown object/value types? Is this controlled in the backend somewhere? (like we only allow some "known" types to be put inside the profiles etc.)
What happens if new types get added in the future? Is there a version control somewhere? Currently we have gecko and processes profile versioning. I think it might be good to make sure that we don't break the profiler when a new type gets added in the future.

canova · 2025-08-12T13:53:59Z

res/css/global.css

+  --number-color: #058b00;
+  --string-color: #dd00a9;
+  --null-color: #5c5c5f;
+  --object-color: #0074e8;
+  --caption-color: #0074e8;
+  --location-color: #5c5c5f;
+  --source-link-color: #0060df;
+  --node-color: #003eaa;
+  --reference-color: #0074e8;
+  --comment-node-color: #5c5c5f;


Are they the variables used inside reps css file?

They are - do you have a suggestion on where they should live, if you'd like them to live elsewhere?

I think it's fine for them to live there. From the package devtools-reps perspective maybe it would be better to have a prefix in their name to make sure that they don't clash with other variables (like --reps-number-color etc.). But since devtools-reps is published already I don't think it's something we should change right away. It might be good to file a bug in the devtools side though. cc @ochameau

src/utils/base64.js

src/types/libdef/npm/devtools-reps_vx.x.x.js

src/utils/value-summaries.js

codecov · 2025-10-17T20:13:44Z

Codecov Report

❌ Patch coverage is 90.27778% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.64%. Comparing base (34edaa4) to head (a55ba14).
⚠️ Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
src/profile-logic/profile-data.ts	57.14%	2 Missing and 1 partial ⚠️
src/components/tooltip/CallNode.tsx	90.00%	1 Missing ⚠️
src/profile-logic/process-profile.ts	83.33%	1 Missing ⚠️
src/test/fixtures/profiles/processed-profile.ts	50.00%	1 Missing ⚠️
src/utils/base64.ts	90.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5363      +/-   ##
==========================================
+ Coverage   85.62%   85.64%   +0.01%     
==========================================
  Files         319      319              
  Lines       31247    31318      +71     
  Branches     8596     8627      +31     
==========================================
+ Hits        26756    26822      +66     
- Misses       4061     4065       +4     
- Partials      430      431       +1

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

canova · 2025-12-09T13:52:26Z

jest.config.js

  ],

+  transform: {
+    '\\.([jt]sx?|mjs)$': 'babel-jest',


nit: it would be good to add a comment here saying that \\.[jt]sx?$ is the default regexp and we change it to make sure that mjs files are included.

canova · 2025-12-09T14:19:58Z

res/css/global.css

+  --number-color: #058b00;
+  --string-color: #dd00a9;
+  --null-color: #5c5c5f;
+  --object-color: #0074e8;
+  --caption-color: #0074e8;
+  --location-color: #5c5c5f;
+  --source-link-color: #0060df;
+  --node-color: #003eaa;
+  --reference-color: #0074e8;
+  --comment-node-color: #5c5c5f;


I think it's fine for them to live there. From the package devtools-reps perspective maybe it would be better to have a prefix in their name to make sure that they don't clash with other variables (like --reps-number-color etc.). But since devtools-reps is published already I don't think it's something we should change right away. It might be good to file a bug in the devtools side though. cc @ochameau

src/profile-logic/stack-timing.ts

src/components/stack-chart/Canvas.tsx

src/types/@types/devtools-reps/index.d.ts

canova · 2025-12-09T15:26:04Z

src/types/profile-derived.ts

  // It's absent in Firefox 97 and before, or in Firefox 98+ when this thread
  // had no extra attribute at all.
  userContextId?: number;
+  tracedObjectShapes?: Array<string[] | null>;


In the src/types/gecko-profile.ts file the string array is not nullable. Is that expected?

package.json

src/components/tooltip/CallNode.tsx

canova · 2025-12-09T17:12:54Z

Oh weird, the main review comment I wrote wasn't send with the rest of the review, thankfully it was saved in another tab. Here's it:

Thanks for all the work! It's working well locally! I added some smaller comments below, but I also wanna talk about some more high concepts (that we can improve later, not necessarily for this PR).

First thing is the sharing the traced values. Since it's a potential PII leak, we should try to be careful. Ideally it would be good to have a checkbox in the sharing panel that's always unchecked by default for traced values, and then share only when the user checks that explicitly. But this is a bit more work. As a first step, we can always strip the traced values for now when we are sharing a profile. Then we can work on a follow-up to add a checkbox in the UI. I can also help with that. But in this PR at least we should remove the traced values by default so we don't leak user info and file a follow-up issue.

To be able to do that, we should update the sanitization code after here to delete the thread fields:

profiler/src/profile-logic/sanitize.ts

Line 406 in 5dd4c64

}

and a very small test here would be great:

profiler/src/test/unit/sanitize.test.ts

Line 35 in 5dd4c64

describe('sanitizePII', function () {

Like we discussed a bit before, another thing to discuss is the UX around the stack chart tooltips. It would be good to make the values expandable. Currently if the object is very nested/large, we miss a lot of values there. But again, this can be worked on as a follow-up. It's good to discuss its UX in a new issue though.

And lastly, I think "Arguments" label looks unaligned in the tooltips:

I assume it's this way since the Reps values are full width, and not like the key-label values above. We can maybe improve the UI if we have a clear separation between the key-label values vs the arguments.

canova

Sorry for the delay on the reviews Alex! And thank you a lot for working on this. I filed #5790 for adding a sanitization step for the traced values.

It looks like this PR bitrotted again (sorry!) :( Could you rebase this on top of the recent main, so we can land it?

I saw one more place to improve in terms of UI, but I think we can also work on that in a follow up. I don't want this PR to bitrot more. See the "No arguments" text here:

So let's land this after rebase.

Changes: [Nazım Can Altınova] Make the range duration text white again (#5792) [Alex Thayer] Display traced values in Stack Chart view (#5363) [Nazım Can Altınova] Improve the JS traced arguments visualization in call node tooltips (#5795) [Markus Stange] Make the argument-values.json profile fixture go through profile upgrading (#5796) [Markus Stange] Add thread.usedInnerWindowIDs to the processed profile format (#5780) [fatadel] Fix context menu and hover preview z-index (#5797) [fatadel] add TrackPower--tooltip-power-microwatt (#5799) [Markus Stange] Two small test fixes (#5801) [fatadel] fix selected thread pid color in light mode (#5805) [Markus Stange] Some fixes to the profile merging code (#5802) [fatadel] fix disabled button color in dark mode (#5808) [fatadel] add comment for uptime label translation (#5806) [Nazım Can Altınova] Add a theme toggle to the home page and follow the system theme by default (#5800) [Nazım Can Altınova] 🔃 Sync: l10n -> main (Feb 4, 2025) (#5813) And huge thanks to our localizers: de: Ger de: Michael Köhler de: Nazım Can Altınova el: Jim Spentzos en-GB: Ian Neal es-CL: ravmn fy-NL: Fjoerfoks ia: Melo46 it: Francesco Lodolo [:flod] nl: Mark Heijl pt-BR: Marcelo Ghelman ru: Valery Ledovskoy sv-SE: Andreas Pettersson tr: Selim Şumlu zh-TW: Pin-guang Chen

squarewave force-pushed the main branch from 20da66f to f917406 Compare February 20, 2025 18:01

This was referenced Mar 6, 2025

Display tracer argument values via DevTool's Reps components #5393

Closed

Display tracer argument values via DevTool's Reps components #5394

Closed

squarewave force-pushed the main branch from f917406 to daf7391 Compare March 26, 2025 19:32

squarewave force-pushed the main branch 2 times, most recently from 72940af to eee6ac3 Compare July 31, 2025 15:28

squarewave marked this pull request as ready for review August 7, 2025 15:39

squarewave requested a review from canova as a code owner August 7, 2025 15:39

canova changed the title ~~[deploy preview] Display traced values in Stack Chart view~~ Display traced values in Stack Chart view Aug 7, 2025

canova requested changes Aug 12, 2025

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canova reviewed Aug 12, 2025

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squarewave force-pushed the main branch from eee6ac3 to 8830789 Compare October 2, 2025 06:37

squarewave force-pushed the main branch from 8830789 to 4c4feed Compare October 17, 2025 20:05

squarewave force-pushed the main branch from 4c4feed to 997d4e1 Compare December 4, 2025 00:06

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squarewave force-pushed the main branch from 997d4e1 to 528faa9 Compare January 15, 2026 06:52

squarewave requested a review from canova January 15, 2026 06:54

canova mentioned this pull request Jan 28, 2026

Add a sanitization checkbox for the traced values that come from the JS execution tracing #5790

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canova approved these changes Jan 28, 2026

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squarewave added 5 commits January 28, 2026 21:28

Handle traced values from JS Execution Tracer profiles

3bd4966

Add test for basic StackChart display of argument values

491d058

lint fixups

b9c3b2d

Review fixups

6c6e9e6

Fix css lint

a55ba14

squarewave force-pushed the main branch from 528faa9 to a55ba14 Compare January 29, 2026 05:32

canova enabled auto-merge January 29, 2026 14:03

canova merged commit c5b8fe9 into firefox-devtools:main Jan 29, 2026
19 checks passed

canova mentioned this pull request Feb 4, 2026

Deploy February 4, 2026 #5814

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