Struct SourceId 

pub struct SourceId(/* private fields */);

0.8.20 Slice 5c (R-20-E3) — the provenance of a canonical row: which source document it is attributable to, and therefore what excise_source must erase when that source is withdrawn.

Why a newtype and not Option<String>. Erasure runs through provenance: a row whose source_id is NULL is reachable by NO excise_source call and is therefore un-erasable. Before 0.8.20 the public PreparedWrite carried source_id: Option<String>, so a caller could express “no provenance” and silently create such a row. A runtime rejection would not have closed this: the facade crate re-exports PreparedWrite and Engine::write is pub, so a caller can build the value directly and skip any validation the engine performs. Replacing the field’s type is what makes the absence of provenance inexpressible rather than merely rejected — the guarantee is enforced by rustc, not by a branch. tests/ui/ in the facade crate holds the compile-fail witness.

This is a BREAKING change, shipped ON by default as part of the 0.8.20 coordinated breaking-pair release. There is deliberately no compatibility shim and no deprecation window: a shim would re-open the hole it closes.

Reserved namespace. Ids beginning with _ belong to the engine and are rejected by SourceId::new. Two are currently minted internally:

• SourceId::ENGINE_PREFIX (_engine:) — rows the engine derives for itself (EXP-S coverage/graph substrate rows), which never pass through PreparedWrite (design §4 item 6).
• SourceId::LEGACY_PRE_0_8_20 (_legacy:pre-0.8.20) — stamped by schema migration step 21 onto pre-0.8.20 rows that were stored with NULL provenance, so they become erasable (R-20-E8). Gated to UNGOVERNED rows only (logical_id IS NULL); a governed row keeps NULL source_id and stays purge-addressable by its logical_id (TC-11 pin).

source_id must not be PII. It survives the erasure it authorises: the excise_source audit row in operational_mutations records it verbatim, and while 0.8.20 makes that audit row durable (design §2 defect D-A) the rule was always that the handle you erase BY must not itself be the thing needing erasure. Use an opaque document id, not an email address.

Implementations

impl SourceId

pub const ENGINE_PREFIX: &'static str = "_engine:"

Reserved prefix for engine-derived rows (design §4 item 6).

pub const LEGACY_PRE_0_8_20: &'static str = "_legacy:pre-0.8.20"

Reserved provenance stamped by schema migration step 21 onto pre-0.8.20 UNGOVERNED rows that were stored with NULL provenance (R-20-E8).

pub fn new(id: impl Into<String>) -> Result<Self, EngineError>

The single public constructor. Rejects the two ways a caller could express “effectively no provenance”:

• an empty or whitespace-only id — it names no source, and excise_source already refuses the empty string, so such a row would be un-erasable in practice;
• an id in the engine’s reserved _-prefixed namespace — a caller who could mint _legacy:pre-0.8.20 could hide rows among the migration’s back-filled ones, or mint _engine: rows that read as engine substrate.

Errors

EngineError::WriteValidation for either rejection above.

pub fn as_str(&self) -> &str

The on-disk source_id text.

pub fn into_string(self) -> String

Consume into the owned on-disk text.

Trait Implementations

impl AsRef<str> for SourceId

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for SourceId

fn clone(&self) -> SourceId

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SourceId

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

Formats the value using the given formatter.

impl Display for SourceId

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

Formats the value using the given formatter.

impl Eq for SourceId

impl Hash for SourceId

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 SourceId

fn cmp(&self, other: &SourceId) -> 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.

impl PartialEq for SourceId

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for SourceId

fn partial_cmp(&self, other: &SourceId) -> 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 SourceId

impl TryFrom<&str> for SourceId

type Error = EngineError

The type returned in the event of a conversion error.

fn try_from(value: &str) -> Result<Self, Self::Error>

Performs the conversion.

impl TryFrom<String> for SourceId

type Error = EngineError

The type returned in the event of a conversion error.

fn try_from(value: String) -> Result<Self, Self::Error>

Performs the conversion.