Struct WriteSelections 

pub struct WriteSelections<'a>(/* private fields */);

A write’s result selection set, guaranteed non-empty.

Why this is a type and not a &[FieldSelection]

An empty selection set is the permissive shape at the write entries, not a neutral one. It is the input to two security decisions at once:

• project_entity filters the returned entity to it — and an empty slice means “no field filtering”, so the whole stored entity is returned;
• selection_set_selects_gated_field decides whether the #423 field authorizer runs at all — and it is false for an empty slice, so the authorizer takes zero calls.

So &[] is not a value a write entry should be able to receive by accident. REST’s anonymous arm passed one (#1352); gRPC reached the same slice a different way, through unwrap_or_default(); and an ordinary mutation { createUser } carried one in from a client document (#1357). Three transports, three spellings, one shape — which is what a type, rather than a fourth grep gate, is for.

Why “non-empty” is sound

Every mutation’s return type is composite (#1358), and GraphQL § 5.3.3 refuses a composite field named without a selection set (#1357), so a document that reaches a write entry always carries one. A transport with no document of its own uses mutation_return_selections, which never returns empty.

new is still fallible rather than an assertion: the compiler is only a gate for schemas that go through the compiler, and schema.compiled.json can be hand-authored. This is the runtime backstop for one that declares a leaf-returning mutation anyway.

Implementations

impl<'a> WriteSelections<'a>

pub fn new(selections: &'a [FieldSelection]) -> Result<Self>

Adopt a selection set for a write.

Errors

Returns FraiseQLError::Validation when selections is empty. See the type docs for why that is a refusal rather than a permissive default.

pub const fn as_slice(self) -> &'a [FieldSelection]

The selection set, for the projector and the field authorizer.

Trait Implementations

impl<'a> Clone for WriteSelections<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for WriteSelections<'a>

impl<'a> Debug for WriteSelections<'a>

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

Formats the value using the given formatter.