Fix "scroll to hotspot" functionality in the source view + assembly view by mstange · Pull Request #5759 · firefox-devtools/profiler

mstange · 2026-01-14T21:08:31Z

Fixes #5758 and cleans things up a bit.

Having the samples passed to getBottomBoxInfoForCallNode will also make it easier to address the TODO about picking the native symbol with the highest sample count, but I'll do that in a separate PR (or probably as part of #5349).

codecov · 2026-01-14T21:11:01Z

Codecov Report

❌ Patch coverage is 66.66667% with 29 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.69%. Comparing base (676b779) to head (98b5328).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
src/profile-logic/bottom-box.ts	51.28%	19 Missing ⚠️
src/components/shared/AssemblyView-codemirror.tsx	50.00%	6 Missing ⚠️
src/components/shared/AssemblyView.tsx	71.42%	2 Missing ⚠️
src/components/shared/SourceView.tsx	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5759      +/-   ##
==========================================
- Coverage   85.70%   85.69%   -0.01%     
==========================================
  Files         315      316       +1     
  Lines       31130    31141      +11     
  Branches     8567     8582      +15     
==========================================
+ Hits        26679    26686       +7     
- Misses       4021     4025       +4     
  Partials      430      430

☔ 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

Thanks for the PR! Looks good to me!

Looks like the first commit is from #5755.

I'm still a bit confused by scrollToLineNumber + highlightedLineNumber but I don't think it's very crucial.

canova · 2026-01-19T16:52:59Z

src/types/profile-derived.ts

+  scrollToLineNumber?: number;
+  highlightLineNumber?: number;


Hmm I can't remember why we had highlighted line on top of scroll to line number.

Edit: Ah, I think it was because of the marker stacks, right? Can we add some comment here and state.ts to explain their usages. It was a bit confusing to me at first.

But also, what happens if we have both scrollToLineNumber and highlightLineNumber, how does it behave. For example, does first highlighting and then scrolling resets the highlight?

That's right, Florian added it when clicking frames in marker stacks. With this patch, highlighting and scrolling are fully independent; and passing highlightLineNumber: undefined will unset the current highlight. So it's different from scrolling where the current scrolling isn't changed if the property isn't specified.

This mismatch suggests that, instead of highlightLineNumber?: number, it might be clearer to have highlightedLineNumber: number | null.

canova · 2026-01-19T17:17:27Z

src/profile-logic/profile-data.ts

    nativeSymbols: nativeSymbolInfos,
-    lineNumber,
+    scrollToLineNumber: lineNumber,
+    highlightLineNumber: lineNumber,


Can they be different, or are they always the same value?

At the moment they're always the same, but the API allows them to be different. Alternatively we could have used a scrollTargetLineIsHighlighted: boolean property.

I want to add a call to a function from line-timings.ts but line-timings.ts already depends on profile-data.ts, and I can't create a circular dependency between profile-data.ts and line-timings.ts.

This means we can compute the right line number for the "hot spot" for the call node that was passed to getBottomBoxInfoForCallNode, and not just for the selected call node. For example, getBottomBoxInfoForCallNode can be called with the right-clicked call node which can be different from the selected call node, and we were scrolling to the wrong spot in that case before this patch. Fixes firefox-devtools#5758.

mstange · 2026-01-19T20:16:39Z

Thanks for the review! I'll adjust the comments to answer the questions you had.

Lots of exciting changes 🎉: [arai-a] Put radio buttons into labels (#5738) [DaniPopes] Update comment for "unique-string" (#5741) [Karan Pradhan] Hide tooltip filter button in non-sticky tooltips and add hideFilterButton tests (#5718) [arai-a] Add a menu to copy the Marker Table as text (#5732) [arai-a] Make the entire list item clickable for the "Full Range" (#5742) [Markus Stange] Move symbol table demangling out of SymbolStore into SymbolProvider (#5746) [Markus Stange] Remove SVG asset imports from profile-data.ts (#5747) [arai-a] Do not apply sticky tooltip on double click (#5754) [arai-a] Skip the ChartCanvas redraw on the Viewport's internal default state usage (#5744) [Markus Stange] Stop blindly extracting uint8array.buffer after calling compress() (#5753) [Markus Stange] In the assembly view state, refer to the current symbol by index (#5755) [Markus Stange] Fix "scroll to hotspot" functionality in the source view + assembly view (#5759) [Markus Stange] Keep the colorField markerSchema field when processing profiles in the gecko format (#5760) [Markus Stange] Implement dark mode (#5740) [Markus Stange] Fix light-mode colors (#5765) [Markus Stange] Tweak dark mode colours. (#5767) [Nazım Can Altınova] Enable some basic type-aware lints (#5775) [Markus Stange] Allow seeing different assembly code for the same function (#5349) [fatadel] Refine tree view a11y (#5779) [fatadel] Align double-click behavior of stack chart with flame graph (#5782) [Markus Stange] Split gz.ts properly into node and browser variants (#5764) [Markus Stange] Simplify and optimize the computation of per-call-node line and address timings (#5770) [Nazım Can Altınova] Move the dark mode toggle to devtools console (#5783) [Nazım Can Altınova] 🔃 Sync: l10n -> main (Jan 27, 2026) (#5785) [Nazım Can Altınova] Improve Chrome importer marker payload logic (#5717) [Markus Stange] Add a Focus Self transform (#5774) [Nazım Can Altınova] Enable the Turkish locale in production (#5786) And huge thanks to our localizers 🎉 : be: Mikalai Udodau de: Ger de: Michael Köhler el: Jim Spentzos en-CA: chutten en-CA: Saurabh en-GB: Ian Neal en-GB: Saurabh es-CL: ravmn fy-NL, nl: Fjoerfoks fr: Skywarp fr: Théo Chevalier fur: Fabio Tomat fy-NL: Fjoerfoks ia: Melo46 it: Francesco Lodolo [:flod] nl: Fjoerfoks nl: Mark Heijl pt-BR: Marcelo Ghelman ru: berry ru: Valery Ledovskoy sv-SE: Andreas Pettersson tr: Grk zh-CN: Olvcpr423 zh-CN: wxie zh-TW: Pin-guang Chen

mstange requested a review from canova January 14, 2026 21:08

mstange self-assigned this Jan 14, 2026

mstange force-pushed the bottom-box-scrolling-improvements branch from 61d7bb8 to 3fdb075 Compare January 15, 2026 15:30

mstange mentioned this pull request Jan 17, 2026

Reduce allocations for getStackLineInfo + getStackAddressInfo #5761

Open

canova approved these changes Jan 19, 2026

View reviewed changes

mstange and others added 7 commits January 19, 2026 14:19

Remove unused prop disableOverscan.

46b51e0

Slightly simplify CallNodeContextMenu props.

583ec0f

Split lineNumber into scrollToLineNumber and highlightedLineNumber

ce4a5f7

Move two functions out of profile-data.ts into a new file bottom-box.ts.

ca1de43

I want to add a call to a function from line-timings.ts but line-timings.ts already depends on profile-data.ts, and I can't create a circular dependency between profile-data.ts and line-timings.ts.

Make assembly view scrolling work like source view scrolling.

0d7cde8

Implement highlightedInstruction support in the assembly view.

4cb91b5

mstange force-pushed the bottom-box-scrolling-improvements branch from 3fdb075 to 7b354c1 Compare January 19, 2026 20:41

mstange enabled auto-merge January 19, 2026 20:41

mstange disabled auto-merge January 19, 2026 20:42

Make it clear that the highlight will be unset when not specified.

98b5328

mstange force-pushed the bottom-box-scrolling-improvements branch from 7b354c1 to 98b5328 Compare January 19, 2026 20:43

mstange enabled auto-merge January 19, 2026 20:43

mstange merged commit 0853138 into firefox-devtools:main Jan 19, 2026
19 checks passed

canova mentioned this pull request Jan 27, 2026

Deploy January 27, 2026 #5787

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Fix "scroll to hotspot" functionality in the source view + assembly view#5759

Fix "scroll to hotspot" functionality in the source view + assembly view#5759
mstange merged 8 commits intofirefox-devtools:mainfrom
mstange:bottom-box-scrolling-improvements

mstange commented Jan 14, 2026 •

edited

Loading

Uh oh!

codecov bot commented Jan 14, 2026 •

edited

Loading

Uh oh!

canova left a comment

Uh oh!

canova Jan 19, 2026

Uh oh!

mstange Jan 19, 2026 •

edited

Loading

Uh oh!

canova Jan 19, 2026

Uh oh!

mstange Jan 19, 2026

Uh oh!

mstange commented Jan 19, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

mstange commented Jan 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

codecov bot commented Jan 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

canova left a comment

Choose a reason for hiding this comment

Uh oh!

canova Jan 19, 2026

Choose a reason for hiding this comment

Uh oh!

mstange Jan 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

canova Jan 19, 2026

Choose a reason for hiding this comment

Uh oh!

mstange Jan 19, 2026

Choose a reason for hiding this comment

Uh oh!

mstange commented Jan 19, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

mstange commented Jan 14, 2026 •

edited

Loading

codecov bot commented Jan 14, 2026 •

edited

Loading

mstange Jan 19, 2026 •

edited

Loading