Welcome to diffuse-cli Discussions!

[PersonofNote]

Hi there! Thanks for joining the discussion.

What am I looking at?

Diffuse is a CLI with accompanying Github actions flow that helps surface the hidden blast radius of a code change that might pass linter and tests and get approved.

It came out of a recurring problem I’ve seen: a “safe-looking” PR that passes CI but subtly breaks behavior downstream in places the author didn’t realize they were touching.

This is a problem that will be familiar to anyone at a large org with business logic/components that are shared across teams. (How many times have you seen a franken-ponent made up of changes stacked on changes as each team re-bandages the same code?) And with LLMs writing more and more of our code, this is happening more often. AI-generated changes are often syntactically correct and well-structured, but they don’t always understand which parts of a system are sensitive. That makes subtle regressions more common, and harder to catch with tests or linters.

Diffuse tries to help by:

• Building a symbol-level dependency graph of your TypeScript project
• Tracing which files/functions/types are affected by a change
• Flagging changes to high-impact symbols (e.g. ones used across many modules)
• Reporting the “blast radius” in CI via a GitHub Action or locally in your terminal

Right now, it:

• Works on any TS/JS repo
• Analyzes staged diffs or a given git range
• Outputs a list of directly and indirectly affected files
• Can comment on PRs with the result, or print to the terminal

Planned features:

• Cross-repo analysis: This is the big, killer feature but also requires a github app and permissions and some infratstructure
• "Hot file" detection: Flag files that are frequently featured in bug reports
• Configurable risk thresholds and suggestions
• Add a gate to high-risk PRs, like adding a second reviewer or requiring at least one of a designated set of higher-level devs to approve

It’s early, and I’m not sure how useful it is yet. Part of why I’m posting here is to find out. If you’ve ever been burned by a change that passed tests but broke something subtle, and especially if you've tried Diffuse, I’d love to hear your thoughts, either here or on this feedback form.

Thanks for engaging!