Bug in save under certain circumstances

[adamnemecek]

Describe the bug

This filter produces an incorrect output.

def rtrim [path:string] {
    open $path | lines | str trim --right | save -r -f $path
}

This filter is supposed to open a file, trim the whitespace and save the file again to the same path. This however instead deletes contents of the file. It seems that it is this particular combination of things. This filter for example works as expected.

# split on two lines
def rtrim [path:string] {
    let lines = open $path | lines 
    $lines | str trim --right | save --raw -f $path
}

This works as well (surprisingly)

# no raw
def rtrim [path:string] {
    open $path | lines | str trim --right | save -f $path
}

and so does this (unsurprisingly)

# dont overwrite
def rtrim [path:string] {
    open $path | lines | str trim --right | save -r "file.md"
}

So it seems to happen only if :

a.) it's a one liner
b.) you are overwriting the file
c.) you are are saving it as raw``

How to reproduce

1.) make file with some line endings
2.) define

def rtrim [path:string] {
    open $path | lines | str trim --right | save -r -f $path
}

3.) run rtrim "file.md"

Expected behavior

The contents of the file should not be deleted.

Screenshots

No response

Configuration

key	value
version	0.92.3
branch	main
commit_hash	c06ef20
build_os	macos-aarch64
build_target	aarch64-apple-darwin
rust_version	rustc 1.79.0-nightly (aa067fb98 2024-04-10)
rust_channel	nightly-aarch64-apple-darwin
cargo_version	cargo 1.79.0-nightly (74fd5bc73 2024-04-10)
build_time	2024-04-15 12:06:25 -07:00
build_rust_channel	release
allocator	mimalloc
features	default, sqlite, trash, which
installed_plugins	plist, gstat, query

Additional context

No response