Enum Error 

pub enum Error {
    Db(Error),
    Compile(PyQLError),
    Decode(DecodeError),
    MissingParam(String),
    InvalidArgument(String),
    ResultCardinality {
        got: usize,
    },
    NoData,
    NoSchemaSnapshot,
    SchemaJson(Error),
    Analyze(String),
    Cache(String),
    UnknownChannel(String),
    MalformedPayload(String),
    Rollback,
}

Variants

Db(Error)

A connection/pool/decode/server-response failure from the driver.

Compile(PyQLError)

PyQL failed to compile — a syntax/type/resolution/cardinality error.

Decode(DecodeError)

A row didn’t fit the type query::<R, _> was asked to decode it into — a shape missing a field the struct declares, an enum label with no matching variant, an integer too wide for its Rust type.

MissingParam(String)

A required query parameter (named or __global__-prefixed) had no matching entry in the params/globals passed by the caller.

InvalidArgument(String)

An argument the query cannot mean — today only a NULL inside an array, which PyQL has no type for. Carries the wording verbatim so every client reports it the same way.

ResultCardinality

query_single/query_required_single (and their _json siblings) got more than one row back.

Fields

got: usize

NoData

query_required_single (and its _json sibling) got zero rows.

NoSchemaSnapshot

Neither pylon migration apply nor pylon migration watch has ever run against this database, so there’s no schema snapshot to load — a bare schema-file edit has no effect until one of those does.

SchemaJson(Error)

Analyze(String)

EXPLAIN’s raw JSON output failed to correlate against the query’s own analyze_paths (pylon_core::analyze::build_coarse_grained).

Cache(String)

A pylon_cache::Cache open/get/put failure — that crate’s own errors are a boxed dyn Error + Send + Sync, not a good match for thiserror’s #[from]/transparent, so this just carries the rendered message.

UnknownChannel(String)

Client::listen(name) — no Channel declared in the schema matches name (bare or module::name).

MalformedPayload(String)

A Client::listen() NOTIFY payload didn’t match its Channel’s own declared shape (bad JSON, a value that doesn’t parse as its declared scalar type, a missing Object field, …).

Rollback

Not a failure: a transaction body asking to be rolled back instead of committed. The Rust counterpart of pylon.Rollback — a body that wants to write, read its own writes and then leave nothing behind (a test, a dry run) returns this. It rides in Error because the body’s return type is Result<T> and there is no T to hand back on a path that deliberately produced nothing; [Client::transaction_opt] turns it into Ok(None) for callers who would rather not see an error at all.

Implementations

impl Error

pub fn sqlstate(&self) -> Option<&SqlState>

The Postgres SQLSTATE code, when this wraps a real server response — None for a compile error or a connection/pool/decode failure.

pub fn is_serialization_error(&self) -> bool

40001 — a serializable/repeatable-read transaction lost a write skew race. Retriable by re-running the whole transaction body.

pub fn is_deadlock(&self) -> bool

40P01 — Postgres broke a deadlock by aborting this transaction. Retriable the same way a serialization failure is.

pub fn is_retriable(&self) -> bool

Either of the two conditions the retrying transaction loop (transaction.rs) automatically retries on.

pub fn is_rollback(&self) -> bool

A deliberate abort (Error::Rollback) rather than a failure — worth distinguishing when a caller drives Client::transaction_with_attempts directly instead of going through Client::transaction_opt.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

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

Provides type-based access to context intended for error reports.

impl From<DecodeError> for Error

fn from(source: DecodeError) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<PyQLError> for Error

fn from(source: PyQLError) -> Self

Converts to this type from the input type.