Flag to not add a crate to a workspace when calling `cargo new`

[Makogan]

Problem

There should be a flag to instruct cargo new not to edit a workspace's root Cargo.toml by appending the crrate to its workspace members.
This PR partially addresses the issue but not entirely. One should be able to call cargo new without it editing the root's Cago.toml even if it has a workspace declaration.

This the situation I am running into. I use spirv-builder at runtime to compile rust source code into spirv for hot reloading of shaders. I thus often run cargo new to initialize the shader crate. However, I am forced to delete it from the workspace members each time, because this crate won't be compiled under the regular cargo workflow. Having a flag to disable the feature would be useful.

Proposed Solution

Add a flag that prevents cargo new from editing a workspace's Cargo.toml

Notes

No response

[epage]

This the situation I am running into. I use spirv-builder at runtime to compile rust source code into spirv for hot reloading of shaders. I thus often run cargo new to initialize the shader crate. However, I am forced to delete it from the workspace members each time, because this crate won't be compiled under the regular cargo workflow. Having a flag to disable the feature would be useful.

If I'm understanding this, it sounds like cargo new is being invoked programmatically with expectations on the results? If so, then that is something intentionally not supported for cargo new.

The assumptions for the not providing a flag were

• The command is meant to be used interactively
• Hand edits on top of what was generated are expected
• By creating a package in a workspace, the intent of wanting it to be a member is very strong.

For myself, I am hesitant to add many flags to customize the behavior of cargo new. Cargo is designed to be opinionated and cargo new in particular is not intended for heavy customization (deferring that to #5151). The closest I could see doing is #8365 since making it a workspace would mean we shouldn't add it as a workspace member.