Enum cargo::core::SourceKind

pub enum SourceKind {
    Git(GitReference),
    Path,
    Registry,
    SparseRegistry,
    LocalRegistry,
    Directory,
}

The possible kinds of code source.

Variants

Git(GitReference)

A git repository.

Path

A local path.

Registry

A remote registry.

SparseRegistry

A sparse registry.

LocalRegistry

A local filesystem-based registry.

Directory

A directory-based registry.

Implementations

impl SourceKind

pub fn protocol(&self) -> Option<&str>

Trait Implementations

impl Clone for SourceKind

fn clone(&self) -> SourceKind

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SourceKind

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Hash for SourceKind

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for SourceKind

Note that this is specifically not derived on SourceKind although the implementation here is very similar to what it might look like if it were otherwise derived.

The reason for this is somewhat obtuse. First of all the hash value of SourceKind makes its way into ~/.cargo/registry/index/github.com-XXXX which means that changes to the hash means that all Rust users need to redownload the crates.io index and all their crates. If possible we strive to not change this to make this redownloading behavior happen as little as possible. How is this connected to Ord you might ask? That’s a good question!

Since the beginning of time SourceKind has had #[derive(Hash)]. It for the longest time also derived the Ord and PartialOrd traits. In #8522, however, the implementation of Ord changed. This handwritten implementation forgot to sync itself with the originally derived implementation, namely placing git dependencies as sorted after all other dependencies instead of first as before.

This regression in #8522 (Rust 1.47) went unnoticed. When we switched back to a derived implementation in #9133 (Rust 1.52 beta) we only then ironically saw an issue (#9334). In #9334 it was observed that stable Rust at the time (1.51) was sorting git dependencies last, whereas Rust 1.52 beta would sort git dependencies first. This is because the PartialOrd implementation in 1.51 used #8522, the buggy implementation, which put git deps last. In 1.52 it was (unknowingly) restored to the pre-1.47 behavior with git dependencies first.

Because the breakage was only witnessed after the original breakage, this trait implementation is preserving the “broken” behavior. Put a different way:

• Rust pre-1.47 sorted git deps first.
• Rust 1.47 to Rust 1.51 sorted git deps last, a breaking change (#8522) that was never noticed.
• Rust 1.52 restored the pre-1.47 behavior (#9133, without knowing it did so), and breakage was witnessed by actual users due to difference with 1.51.
• Rust 1.52 (the source as it lives now) was fixed to match the 1.47-1.51 behavior (#9383), which is now considered intentionally breaking from the pre-1.47 behavior.

Note that this was all discovered when Rust 1.53 was in nightly and 1.52 was in beta. #9133 was in both beta and nightly at the time of discovery. For 1.52 #9383 reverted #9133, meaning 1.52 is the same as 1.51. On nightly (1.53) #9397 was created to fix the regression introduced by #9133 relative to the current stable (1.51).

That’s all a long winded way of saying “it’s weird that git deps hash first and are sorted last, but it’s the way it is right now”. The author of this comment chose to handwrite the Ord implementation instead of the Hash implementation, but it’s only required that at most one of them is hand-written because the other can be derived. Perhaps one day in the future someone can figure out how to remove this behavior.

fn cmp(&self, other: &SourceKind) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for SourceKind

fn eq(&self, other: &SourceKind) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for SourceKind

Forwards to Ord

fn partial_cmp(&self, other: &SourceKind) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for SourceKind

impl StructuralPartialEq for SourceKind

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes

Size for each variant:

• Git: 32 bytes
• Path: 0 bytes
• Registry: 0 bytes
• SparseRegistry: 0 bytes
• LocalRegistry: 0 bytes
• Directory: 0 bytes