what is bun-windows-shared-cache-repro fr?

This project is a small test setup built to demonstrate and confirm a specific bug in Bun, a fast JavaScript package manager and runtime, on Windows computers. It reproduces a reported issue where installing packages with Bun fails when multiple installs happen at the same time and share a cold cache folder that has not been used yet, and it compares that behavior against two other popular package managers, npm and pnpm, to see if they have the same problem. The test script starts several separate, independent projects at once, each trying to install the same small set of common packages like express, lodash, and zod, all pointing at one shared cache location. It repeats this process over several rounds and records how many installs succeed or fail for each package manager being tested. The results are stark. In this repository's tests, Bun 1.3.14 failed all 32 install attempts across four rounds, with errors related to file system race conditions, meaning multiple processes tried to write to the same cache location at the same time and got confused. In contrast, npm and pnpm completed all 40 of their attempts with zero failures under the same conditions. The author explains that Windows has stricter rules than Mac or Linux about replacing files and folders while other programs might be using them, which makes this kind of parallel installation trickier to get right. npm and pnpm are built to handle these races safely, while Bun's current approach runs into conflicts when multiple installs try to publish the same extracted package folder into the cache simultaneously. This project is useful for developers debugging Bun reliability issues on Windows, or anyone deciding which package manager to trust for concurrent installs in a Windows-based build pipeline.