Struct Branch 

#[non_exhaustive]
pub struct Branch {
    pub id: BranchId,
    pub parent: Option<BranchId>,
    pub forked_at: Option<String>,
    pub created_at: String,
}

One row of branches: a lineage, its parent, and where it was cut.

#[non_exhaustive] costs nothing here, and that is a fact about direction

EdgeBelief needed a constructor to go with the attribute, because save_snapshot is public and takes one — without EdgeBelief::new the attribute would not have made the next field additive, it would have made a public function uncallable (0.14.5). This type only ever travels outward: Database::branches returns it and nothing public accepts it. So the attribute buys the additive field and takes nothing back, and no constructor is owed. §15.4’s abandonment arm is the field it is being kept open for.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

id: BranchId

The lineage’s own name.

parent: Option<BranchId>

The lineage it was cut from, or None for the trunk.

forked_at: Option<String>

The transaction-time instant it was cut at, or None for the trunk.

This is the visibility cutoff 0.14.6 reads: the branch sees its parent’s history up to and including this instant, and nothing the parent records after it (D-223).

created_at: String

When the row was written.

A separate column from forked_at rather than a duplicate of it, and the two are equal for every branch this release can create. They are separate so that forking from a past instant is an additive change later: a historical fork has a forked_at behind its created_at, and the schema has always allowed it — CHECK (forked_at <= created_at).

Trait Implementations

impl Clone for Branch

fn clone(&self) -> Branch

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Branch

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

Formats the value using the given formatter.

impl Eq for Branch

impl Hash for Branch

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

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 Branch

fn cmp(&self, other: &Branch) -> 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,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for Branch

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Branch

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

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

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

Tests less than (for self and other) and is used by the < operator.

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

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

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

Tests greater than (for self and other) and is used by the > operator.

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

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

impl StructuralPartialEq for Branch