fix(web): exclude PostHog proxy from i18n middleware by lawrencecchen · Pull Request #1626 · manaflow-ai/cmux

lawrencecchen · 2026-03-17T23:24:10Z

Summary

The i18n middleware added in cf75da8f intercepts /cmuxterm/* requests (PostHog reverse proxy), breaking all analytics since March 12.
Add cmuxterm to the middleware matcher's negative lookahead so PostHog proxy requests bypass i18n routing.

Testing

Verify pageviews resume on PostHog dashboard after deploy.
Confirm i18n locale detection still works for all other routes.

Summary by cubic

Switch PostHog to the managed reverse proxy at https://r.cmux.dev and remove the /cmuxterm rewrites, eliminating the i18n matcher conflict and restoring analytics. Rename the middleware to web/proxy.ts for Next.js 16; locale detection for other routes is unchanged.

^{Written for commit 4e6a0b8. Summary will update on new commits.}

Summary by CodeRabbit

Chores
- Broadened route-matching exclusions to omit additional paths from standard processing, refining request handling.
Bug Fixes / Maintenance
- Removed legacy proxy rewrite rules that routed certain paths through external rewrite mappings.
Telemetry
- Switched analytics initialization to use an absolute analytics endpoint URL to ensure consistent event delivery.

The next-intl middleware added in cf75da8 intercepts /cmuxterm/* requests (the PostHog reverse proxy), causing analytics to break since March 12. Add cmuxterm to the negative lookahead so proxy requests bypass i18n.

vercel · 2026-03-17T23:24:15Z

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
cmux	Ready	Preview, Comment	Mar 17, 2026 11:43pm

chatgpt-codex-connector · 2026-03-17T23:24:16Z

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.
To continue using code reviews, add credits to your account and enable them for code reviews in your settings.

greptile-apps

Your free trial has ended. If you'd like to continue receiving code reviews, you can add a payment method here.

coderabbitai · 2026-03-17T23:24:30Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 46e5df7a-ffee-4f11-bfa9-988ab7d2f914

📥 Commits

Reviewing files that changed from the base of the PR and between aa00c5d and 4e6a0b8.

📒 Files selected for processing (3)

web/app/[locale]/posthog.tsx
web/next.config.ts
web/proxy.ts

💤 Files with no reviewable changes (1)

web/next.config.ts

📝 Walkthrough

Walkthrough

Updated middleware matcher to exclude cmuxterm; switched PostHog api_host from a relative path to https://r.cmux.dev; removed Next.js rewrites that proxied /cmuxterm/* and /cmuxterm/static/*.

Changes

Cohort / File(s)	Summary
Middleware Route Configuration `web/proxy.ts`	Changed `config.matcher` negative lookahead to also exclude `cmuxterm` (`"/((?!api
Analytics Config `web/app/[locale]/posthog.tsx`	PostHog initialization: `api_host` changed from `"/cmuxterm"` to absolute URL `https://r.cmux.dev`; other PostHog options unchanged.
Next.js Rewrites Removed `web/next.config.ts`	Removed `async rewrites()` containing two rewrite rules that proxied `/cmuxterm/static/:path` and `/cmuxterm/:path` to external PostHog hosts.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I hopped through lines of route and host,
I nudged cmuxterm off the middleware post,
Swapped a path for a shiny domain,
Rewrites gone — the mapping changed its frame,
A tiny hop, a tidy code-toast 🥕✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: excluding PostHog proxy from i18n middleware. It directly addresses the core issue and is clear, specific, and concise.
Description check	✅ Passed	The description includes a clear summary of the problem and solution, testing instructions, and related context. However, the Testing section lacks detail about how the changes were verified locally, and the Review Trigger, Checklist sections are not completed.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch fix-posthog-middleware

📝 Coding Plan

Generate coding plan for human review comments

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

cubic-dev-ai

No issues found across 1 file

Next.js 16 renamed middleware.ts to proxy.ts. Migrate to the new convention since we're on Next.js 16.1.6.

Replace the Next.js rewrites-based proxy (/cmuxterm -> us.i.posthog.com) with PostHog's managed reverse proxy at r.cmux.dev. This removes the rewrites from next.config.ts entirely and eliminates the proxy.ts matcher conflict that caused the analytics regression.

cubic-dev-ai

1 issue found across 3 files (changes from recent commits).

Prompt for AI agents (unresolved issues)


Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="web/proxy.ts">

<violation number="1">
P1: `cmuxterm` was removed from the exclusion matcher, so `/cmuxterm/*` is routed through i18n middleware again and the PostHog proxy path will be intercepted.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

* fix(web): exclude PostHog proxy path from i18n middleware The next-intl middleware added in 1476b2e intercepts /cmuxterm/* requests (the PostHog reverse proxy), causing analytics to break since March 12. Add cmuxterm to the negative lookahead so proxy requests bypass i18n. * refactor(web): rename middleware.ts to proxy.ts for Next.js 16 Next.js 16 renamed middleware.ts to proxy.ts. Migrate to the new convention since we're on Next.js 16.1.6. * feat(web): migrate PostHog to managed reverse proxy at r.cmux.dev Replace the Next.js rewrites-based proxy (/cmuxterm -> us.i.posthog.com) with PostHog's managed reverse proxy at r.cmux.dev. This removes the rewrites from next.config.ts entirely and eliminates the proxy.ts matcher conflict that caused the analytics regression. --------- Co-authored-by: Lawrence Chen <lawrencecchen@users.noreply.github.com>

fix(web): exclude PostHog proxy path from i18n middleware

a257290

The next-intl middleware added in cf75da8 intercepts /cmuxterm/* requests (the PostHog reverse proxy), causing analytics to break since March 12. Add cmuxterm to the negative lookahead so proxy requests bypass i18n.

greptile-apps Bot reviewed Mar 17, 2026

View reviewed changes

vercel Bot deployed to Preview March 17, 2026 23:24 View deployment

cubic-dev-ai Bot reviewed Mar 17, 2026

View reviewed changes

refactor(web): rename middleware.ts to proxy.ts for Next.js 16

aa00c5d

Next.js 16 renamed middleware.ts to proxy.ts. Migrate to the new convention since we're on Next.js 16.1.6.

vercel Bot deployed to Preview March 17, 2026 23:40 View deployment

vercel Bot deployed to Preview March 17, 2026 23:43 View deployment

cubic-dev-ai Bot reviewed Mar 17, 2026

View reviewed changes

lawrencecchen merged commit 93d2245 into main Mar 18, 2026
14 checks passed

lawrencecchen deleted the fix-posthog-middleware branch March 18, 2026 00:02

coderabbitai Bot mentioned this pull request Mar 26, 2026

Fix SEO indexing: hreflang, canonicals, sitemap, trailing slash #2193

Merged

coderabbitai Bot mentioned this pull request Apr 20, 2026

Bring minimal macOS auth scaffolding to main #3027

Merged

4 tasks

This was referenced May 1, 2026

Add agent-readable page variants #3410

Merged

Redirect /changelog to /docs/changelog (307) #3668

Merged

Navigation Menu

Repository navigation

fix(web): exclude PostHog proxy from i18n middleware - #1626

fix(web): exclude PostHog proxy from i18n middleware#1626
lawrencecchen merged 3 commits into
mainfrom
fix-posthog-middleware

lawrencecchen commented Mar 17, 2026 •

edited by coderabbitai Bot

Loading

Uh oh!

vercel Bot commented Mar 17, 2026 •

edited

Loading

Uh oh!

chatgpt-codex-connector Bot commented Mar 17, 2026

Uh oh!

greptile-apps Bot left a comment

Uh oh!

coderabbitai Bot commented Mar 17, 2026 •

edited

Loading

Walkthrough

Changes

Estimated code review effort

Poem

Uh oh!

cubic-dev-ai Bot left a comment

Uh oh!

cubic-dev-ai Bot left a comment

Uh oh!

Uh oh!

This branch was successfully deployed

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Conversation

lawrencecchen commented Mar 17, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Testing

Related

Summary by cubic

Summary by CodeRabbit

Uh oh!

vercel Bot commented Mar 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

chatgpt-codex-connector Bot commented Mar 17, 2026

Uh oh!

greptile-apps Bot left a comment

Choose a reason for hiding this comment

Uh oh!

coderabbitai Bot commented Mar 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Walkthrough

Changes

Estimated code review effort

Poem

Uh oh!

cubic-dev-ai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

cubic-dev-ai Bot left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

This branch was successfully deployed

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

lawrencecchen commented Mar 17, 2026 •

edited by coderabbitai Bot

Loading

vercel Bot commented Mar 17, 2026 •

edited

Loading

coderabbitai Bot commented Mar 17, 2026 •

edited

Loading