perf(web): pull request comments reuse their markdown parse #27808 · pingdotgg/t3code

	Code tab, before	Code tab, after	Timeline tab, before	Timeline tab, after
Main-thread task time	55.6 / 51.5 s	46.2 / 46.4 s	58.4 / 57.7 s	48.4 / 52.5 s
Script time	37.6 / 33.7 s	25.9 / 26.4 s	40.9 / 39.2 s	30.1 / 32.3 s
Blocking time in long frames	32.5 / 29.5 s	20.8 / 20.6 s	33.9 / 34.8 s	24.9 / 26.8 s
JS heap peak	992 / 973 MB	620 / 601 MB	1,185 / 1,068 MB	852 / 780 MB
micromark CPU	1.7 / 1.3 s	0.86 / 0.80 s	2.2 / 2.0 s	1.0 / 1.0 s

MmacroscopeappBotapproved these changes · review dismissed1d ago

Approvability

Verdict: Approved at f9469bc

Macroscope's review found this PR approvable — Pull-request comments and thought previews reuse stable markdown plugin configurations to avoid repeated parsing. The change preserves rendering safeguards and uses the existing bounded content cache, with no persistent-data or permission changes.

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CcoderabbitaiBot1d ago

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External image Run configuration

Source mode: Auto
Repository: pingdotgg/t3code
Branch: t3/pr-markdown-cache
File: .coderabbit.config.ts
Commit: 70ab7b0
Layers: Repository TS config
Review profile: CHILL
Plan: Team
Run ID: e2eb9a34-ba3b-4067-9502-fa9eb3836199

External image Commits

Reviewing files that changed from the base of the PR and between 0ce257b8804a7a6dffa2892a280a59dd20e5a159 and 70ab7b0d67092b35ceee5ed926d8b35bf73f2a9c.

External image Files selected for processing: 8

apps/web/src/components/ChatMarkdown.browser.test.tsx
apps/web/src/components/ChatMarkdown.tsx
apps/web/src/components/chat/TimelineWorkEntryRow.logic.ts
apps/web/src/components/chat/TimelineWorkEntryRow.tsx
apps/web/src/components/chat/TimelineWorkGroupRows.tsx
apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
apps/web/src/components/pullRequest/PullRequestMarkdown.tsx
apps/web/src/components/pullRequest/pullRequestMarkdown.logic.ts

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Walkthrough

ChatMarkdown now reuses combined plugin lists for stable extra plugins. Thought-preview renderers use shared plugin lists, and pull-request Markdown supplies cached autolink plugins through its context.

Changes: Markdown plugin cache reuse

Layer / File(s)	Summary
Reuse extra plugin lists `apps/web/src/components/ChatMarkdown.tsx`, `apps/web/src/components/ChatMarkdown.browser.test.tsx`	ChatMarkdown reuses combined shared and extra plugin lists. Extra plugins alone no longer select the uncached renderer path. A test checks that a stable plugin callback runs once across renders.
Use stable thought-preview plugins `apps/web/src/components/chat/TimelineWorkEntryRow.logic.ts`, `apps/web/src/components/chat/TimelineWorkEntryRow.tsx`, `apps/web/src/components/chat/TimelineWorkGroupRows.tsx`	The timeline renderers use exported thought and thinking plugin lists. The reasoning preview selects a list based on whether its tool lifecycle status is `inProgress`.
Pass cached autolink plugins to Markdown `apps/web/src/components/pullRequest/pullRequestMarkdown.logic.ts`, `apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx`, `apps/web/src/components/pullRequest/PullRequestMarkdown.tsx`	The detail panel provides a cached autolink plugin list in the Markdown context. PullRequestMarkdown passes that list to ChatMarkdown.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Refactor

Possibly related issues

pingdotgg/t3code#9661: This change adds renderer and parse-cache reuse for pull-request Markdown and thought previews, matching the issue’s performance-audit scope.
pingdotgg/t3code#22985: Stable thought-preview plugin lists support cache reuse in the area of expensive reasoning-preview transformations described in the issue.

Possibly related PRs

pingdotgg/t3code#27480: It introduced shared renderer instances and rendered-Markdown caching that this change extends to stable extra plugin lists.
pingdotgg/t3code#21626: It added parsed-Markdown caching and renderer memoization used by these plugin-list changes.
pingdotgg/t3code#23997: It introduced the change-request autolinker used to create the cached pull-request plugin list.

Suggested reviewers: maria-rcks, macroscopeapp, t3dotgg

Merge Risk: External image Minimal · up to 70ab7

No merge-blocking issue was identified in the Markdown cache changes.

Pre-merge checks: ^Passed 3 · ^Failed 1

^Failed Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Description check	Warning	The description follows the repository template. It has a Problem section that states the cause and impact: unstable autolink plugin lists broke ChatMarkdown memoization and parse caching. It has a Ch…	Add a Scope and approval section. Link the triaged bug issue or the discussion with maintainer approval, including the approval comment. If no prior issue exists, explain why this focused performance fix qualifies without one. The descripti…

^Passed Passed checks: 3 passed

Check name	Status	Explanation
Title check	Passed	The title "perf(web): pull request comments reuse their markdown parse" matches the main change. The PR makes pull request comments reuse the shared Markdown parse cache by building a stable autolink …
Linked Issues check	Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	Passed	Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title "perf(web): pull request comments reuse their markdown parse" matches the main change. The PR makes pull request comments reuse the shared Markdown parse cache by building a stable autolink plugin list once per repository. The title uses a conventional commit format and is specific to the primary change.

Full details: Description check

Explanation

The description follows the repository template. It has a Problem section that states the cause and impact: unstable autolink plugin lists broke ChatMarkdown memoization and parse caching. It has a Change section that lists the fix. Its Verification section gives a focused test (2 parses on main, 1 on this branch) and stress-rig measurements. The Scope and approval section is missing. It does not link a triaged issue or maintainer approval, and it does not explain why the change qualifies without one. The template also asks for the model and harness used, and the description includes 'Built by Claude Opus 5.5 in Claude Code, running in T3 Code', so that item is covered.

Resolution

Add a Scope and approval section. Link the triaged bug issue or the discussion with maintainer approval, including the approval comment. If no prior issue exists, explain why this focused performance fix qualifies without one. The description should also add a short, explicit Problem heading statement; the current text is present but not under the template headings. Also state what could not be checked, if anything. The stress-rig results are measured in a separate tool run and the description does not give the browser or machine details needed to reproduce them.

Finishing Touches

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🧪 Generate unit tests (beta)

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MmacroscopeappBotapproved these changes22h ago

perf(web): pull request comments reuse their markdown parse#27808

Stress rig

Checks

Failing1

Approvability