Add flag to ignore all parent directory configs

[stevenroose]

Describe the problem you are trying to solve
Cargo often behaves very unexpectedly and often the cause of this is .cargo/config files or Cargo.toml workspace definitions in one of the parent directories. One example of an issue that could have been workaround with this feature is #7620.

Describe the solution you'd like
A flag --no-parent or something along those lines that makes cargo totally independent from configurations set in parent directories.

[epage]

In some tools, I've seen them have an --isolated flag that causes it to not implicitly load any config, leaving it only to the --config flag / env variables.

[lure23]

Yes, please.

As a newcomer to Rust and Cargo, I am surprised there is not this option. Causes me to rearrange project folders, to avoid a parent relationship (makes the main project a "sister"). The particular "culprit" here is also Embassy - or maybe it's just the way it's used here -, which uses .cargo/config.toml for things that aren't strictly environment related but project level.

While there are efforts underway to move such things to normal Cargo.toml, I haven't found a way to move that link-arg=-Tdefmt.x line. It would certainly help to be able to cut the cord with a parent folder.