How to debug mysterious deletion of files?

[vineetdigit]

I am developing a node (v16.15.0) application that uses nodegit to manage git repos. Every once in a while some files from the git repo and/or working directory mysteriously disappear and the repository stops being a valid git repo. If I performed any git command, I get following error

fatal: not a git repository (or any of the parent directories): .git

total 0
drwxr-xr-x   2 vineet  wheel   64 May 12 16:55 hooks
drwxr-xr-x   2 vineet  wheel   64 May 12 16:55 info
drwxr-xr-x  12 vineet  wheel  384 May 12 16:55 objects
drwxr-xr-x   3 vineet  wheel   96 May 12 16:55 refs

As you can see there are few directories left in .git. Usually there are more files here.

Application only reads/writes files to the working directory but never deletes them. It's using node's fs module for file system read/write. For all git related stuff, nodegit obviously uses filesystem internally to read/write to .git, but my application never directly accesses .git

I've tried to observe when this happens and how frequently it happens. So far it has happened a 3-4 times over the course of couple of months. I can't actually pin point or repro. The last time it happened was when I had put my macbook to sleep while the node application was still running. After waking up I started seeing this error.

The files in the working directly that have disappeared are all the files read (but not updated after creation) by the application. Files that were not deleted were files my application only just created (as a result of a new api I'm still developing and I only got the creation part working so far). These files are not yet read by my application.

In the course of product development, I'm restarting my application all the time (nodemon) and I often put my macbook in sleep mode between breaks.

Since I'm losing files from both .git and working directly, this makes me wonder if I can rule out nodegit.

Secondly, I have no idea where even begin to debug this. I am going to try using 'fs_usage' next.

Any suggestions on how I can try to understand when/why this happens?

[bnoordhuis]

On Linux you'd use strace to record file operations and stack traces. On macOS... maybe dtruss? Requires root and isn't nearly as polished as strace though.