Implemented FromStr for CString and TryFrom<CString> for String

[YohDeadfall]

The motivation of this change is making it possible to use CString in generic methods with FromStr and TryInto<String> trait bounds. The same traits are already implemented for OsString which is an FFI type too.

[rustbot]

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[workingjubilee]

This is a request to stabilize a trait, and as such needs a FCP from libs-api.

[YohDeadfall]

Is anything required from my side now?

[workingjubilee]

No. You could choose to provide additional explanatory justification for why this should be accepted, if you wish, but it's not required.

[YohDeadfall]

Then there's nothing to add, actually. It's all about usability of the CString type in generics and orphan rules preventing from having these traits on the type. The issue can be worked around by making another trait for string types, but it's better to fix the issue in the first place since OsString is already doing that right.

[zachs18]

It might be good to explicitly document that this does not require a terminating NUL in the input, maybe something like

Suggested change

	#[inline]
	fn from_str(s: &str) -> Result<Self, Self::Err> {
	Self::new(s)
	}
	/// Creates a new C-compatible string from a `&str`.
	///
	/// The trailing 0 byte will be appended by this function. If the provided data
	/// contains any 0 bytes in it, `Err(NulError)` will be returned.
	#[inline]
	fn from_str(s: &str) -> Result<Self, Self::Err> {
	Self::new(s)
	}

or maybe just link to the docs for CString::new.

[YohDeadfall]

Added a short description with a link to the corresponding function, and also did the same for the backward conversion.

[joshtriplett]

@rfcbot merge

[rfcbot]

Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @m-ou-se

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

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[joshtriplett]

Needs to use TryFrom not TryInto.

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[slanterns]

A squash is favorable.

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

[workingjubilee]

@bors r+

[bors]

📌 Commit 3025513 has been approved by workingjubilee

It is now in the queue for this repository.