Behind the scenes of Bun Install

Developer Experiences and Compatibility

• Several commenters enjoy Bun’s built‑in server, SQLite, speed, and “one binary” simplicity; some use it for all new scripts and small servers.
• Others repeatedly hit incompatibilities and reverted to Node: past issues with crypto, Playwright/Crawlee, Storybook, streams closing early, Docker hangs, SQLite bugs, and memory leaks.
• A recurring strategy is using Bun only as package manager and/or test runner, while keeping Node as the runtime.
• There’s mention that Playwright and some HTTP client incompatibilities have been or are being fixed, but “rough edges” remain a deterrent for production use.

Adoption, Ecosystem, and Governance

• Data shared from GitHub shows new repos overwhelmingly using npm and pnpm over Bun, raising questions about slow adoption.
• Many see Node as mature, community‑driven, and battle‑tested, whereas Bun and Deno are perceived as VC‑funded, less “democratic,” with potential lock‑in risk.
• Some argue Bun doesn’t yet offer a 10x or clear 2x advantage for real projects; incremental gains may be absorbed as Node copies good ideas.
• Others counter that even if Bun just forces Node to improve, it has “succeeded.”

Performance, Benchmarks, and Install Speed

• Bun install is praised as dramatically faster; some share local benchmarks where Bun, npm, pnpm, and Deno end up closer than marketing implies.
• Skepticism arises around Bun’s blog benchmarks: unclear cache clearing, missing “npm (cached)” entry, and interpretation of syscall overhead numbers.
• There’s debate whether install speed matters: some say installs are rare and not a bottleneck; others stress CI/CD and human focus loss from 20–60 second waits.

Design Choices: IO, Syscalls, and Tarballs

• Discussion of Bun avoiding libuv, using Zig with direct syscalls, and optimizing for fewer context switches; some note Node could in theory do the same in C/C++.
• gzip footer and tarball handling: Bun buffers the whole tarball, reads the uncompressed size from the gzip trailer, and pre‑allocates output to avoid repeated reallocations; tradeoffs vs streaming are debated.
• Questions raised about equivalence of Linux hardlinks vs macOS clonefile and implications for shared files.

Comparisons with Other Runtimes and Package Managers

• Deno’s Node compatibility is said to have improved significantly; its URL‑based dependency model makes apples‑to‑apples benchmarks tricky.
• One commenter posts numbers: on a React app, Bun and Deno installs (with lockfiles) are in the same ballpark as npm; first‑time runs differ more.
• Broader ecosystem talk: Python’s uv, Ruby’s rv and Bundler, PHP’s Composer and Mago, and Nix‑based workflows are cited as analogues.

Zig, Stability, and Safety

• Some worry about Bun’s crash‑heavy issue tracker and Zig’s pre‑1.0 status; others note Node itself relies on unsafe C/C++ and that maturity/testing matter more than language.
• Debate around whether Zig’s ecosystem is “mature”: strong C interop vs relatively few pure‑Zig libraries.

Reception of the Article

• The article is widely praised as clear, engaging technical writing tying low‑level concepts (syscalls, locality, compression, filesystems) to developer tooling.
• A few nitpick factual claims about historical hardware performance and suspect some LLM‑like rhetoric, but overall the technical explanations are considered strong.