API ergonomics & consistency pass (pre-tag)

.gitignore

@@ -328,7 +328,8 @@ fuzz/corpus/
 fuzz/artifacts/
 
 .omniscient/
-
+omniscient.toml
 .DS_Store
+.superpowers/
 
 omniscient.toml

src/dtc/ext_data.rs

@@ -49,7 +49,7 @@ impl DTCExtDataRecordNumber {
     /// Return the raw `u8` value of this record number.
     #[must_use]
     #[allow(clippy::match_same_arms)]
-    pub fn value(&self) -> u8 {
+    pub const fn value(&self) -> u8 {
         match self {
             Self::ISOSAEReserved(value) => *value,
             Self::VehicleManufacturer(value) => *value,

src/dtc/snapshot.rs

@@ -32,7 +32,7 @@ impl DTCSnapshotRecordNumber {
     /// Return the raw `u8` value of this snapshot record number.
     #[must_use]
     #[allow(clippy::match_same_arms)]
-    pub fn value(&self) -> u8 {
+    pub const fn value(&self) -> u8 {
         match self {
             DTCSnapshotRecordNumber::Reserved(value) => *value,
             DTCSnapshotRecordNumber::Number(value) => *value,

src/dtc/status.rs

@@ -131,7 +131,7 @@ impl<'a> Decode<'a> for DTCStatusMask {
 #[allow(non_camel_case_types)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 #[non_exhaustive]
 #[repr(u8)]
 pub enum DTCFormatIdentifier {
@@ -299,7 +299,7 @@ pub enum FunctionalGroupIdentifier {
 impl FunctionalGroupIdentifier {
     /// Return the raw `u8` value of this functional group identifier.
     #[must_use]
-    pub fn value(&self) -> u8 {
+    pub const fn value(&self) -> u8 {
         match self {
             FunctionalGroupIdentifier::EmissionsSystemGroup => 0x33,
             FunctionalGroupIdentifier::SafetySystemGroup => 0xD0,

src/lib.rs

@@ -37,19 +37,20 @@ pub use service::UdsServiceType;
 
 mod services;
 pub use services::{
-    ClearDiagnosticInfoRequest, CommunicationControlRequest, CommunicationControlResponse,
-    CommunicationControlType, CommunicationType, ControlDTCSettingsRequest,
-    ControlDTCSettingsResponse, DiagnosticSessionControlRequest, DiagnosticSessionControlResponse,
-    DiagnosticSessionType, DirSizePayload, DtcAndStatusIter, DtcFaultDetectionIter, DtcSettings,
-    DtcSeverityAndStatusIter, EcuResetRequest, EcuResetResponse, FileOperationMode,
-    FileSizePayload, NamePayload, NegativeResponse, PositionPayload, ReadDTCInfoRequest,
-    ReadDTCInfoResponse, ReadDTCInfoSubFunction, ReadDataByIdentifierRequest,
-    RequestDownloadRequest, RequestDownloadResponse, RequestFileTransferRequest,
-    RequestFileTransferResponse, RequestTransferExitRequest, RequestTransferExitResponse,
-    ResetType, RoutineControlRequest, RoutineControlResponse, RoutineControlSubFunction,
-    SecurityAccessLevel, SecurityAccessRequest, SecurityAccessResponse, SecurityAccessType,
-    SentDataPayload, SizePayload, TesterPresentRequest, TesterPresentResponse, TransferDataRequest,
-    TransferDataResponse, WriteDataByIdentifierRequest, WriteDataByIdentifierResponse,
+    ClearDiagnosticInfoRequest, ClearDiagnosticInfoResponse, CommunicationControlRequest,
+    CommunicationControlResponse, CommunicationControlType, CommunicationType,
+    ControlDTCSettingsRequest, ControlDTCSettingsResponse, DiagnosticSessionControlRequest,
+    DiagnosticSessionControlResponse, DiagnosticSessionType, DirSizePayload, DtcAndStatusIter,
+    DtcFaultDetectionIter, DtcSettings, DtcSeverityAndStatusIter, EcuResetRequest,
+    EcuResetResponse, FileOperationMode, FileSizePayload, NamePayload, NegativeResponse,
+    PositionPayload, ReadDTCInfoRequest, ReadDTCInfoResponse, ReadDTCInfoSubFunction,
+    ReadDataByIdentifierRequest, ReadDataByIdentifierResponse, RequestDownloadRequest,
+    RequestDownloadResponse, RequestFileTransferRequest, RequestFileTransferResponse,
+    RequestTransferExitRequest, RequestTransferExitResponse, ResetType, RoutineControlRequest,
+    RoutineControlResponse, RoutineControlSubFunction, SecurityAccessLevel, SecurityAccessRequest,
+    SecurityAccessResponse, SecurityAccessType, SentDataPayload, SizePayload, TesterPresentRequest,
+    TesterPresentResponse, TransferDataRequest, TransferDataResponse, WriteDataByIdentifierRequest,
+    WriteDataByIdentifierResponse,
 };
 
 #[cfg(test)]

src/response.rs

@@ -1,9 +1,10 @@
 use crate::{
-    CommunicationControlResponse, ControlDTCSettingsResponse, Decode,
+    ClearDiagnosticInfoResponse, CommunicationControlResponse, ControlDTCSettingsResponse, Decode,
     DiagnosticSessionControlResponse, EcuResetResponse, Encode, Error, NegativeResponse,
-    ReadDTCInfoResponse, RequestDownloadResponse, RequestFileTransferResponse,
-    RequestTransferExitResponse, RoutineControlResponse, SecurityAccessResponse,
-    TesterPresentResponse, TransferDataResponse, UdsServiceType, WriteDataByIdentifierResponse,
+    ReadDTCInfoResponse, ReadDataByIdentifierResponse, RequestDownloadResponse,
+    RequestFileTransferResponse, RequestTransferExitResponse, RoutineControlResponse,
+    SecurityAccessResponse, TesterPresentResponse, TransferDataResponse, UdsServiceType,
+    WriteDataByIdentifierResponse,
 };
 
 /// Parsed zero-copy UDS response. Borrows from the wire buffer.
@@ -14,7 +15,7 @@ use crate::{
 #[non_exhaustive]
 pub enum Response<'a> {
     /// Positive response to `ClearDiagnosticInfo`.
-    ClearDiagnosticInfo,
+    ClearDiagnosticInfo(ClearDiagnosticInfoResponse),
     /// Positive response to `CommunicationControl`.
     CommunicationControl(CommunicationControlResponse),
     /// Positive response to `ControlDTCSettings`.
@@ -34,7 +35,7 @@ pub enum Response<'a> {
     /// cannot split it into `(DID, value)` pairs. Parse it caller-side once you know each
     /// DID's record length — read the 2-byte big-endian DID, take the application-defined
     /// number of data bytes, then repeat on the remainder.
-    ReadDataByIdentifier(&'a [u8]),
+    ReadDataByIdentifier(ReadDataByIdentifierResponse<'a>),
     /// Positive response to `ReadDTCInformation` with lazy iterators.
     ReadDTCInfo(ReadDTCInfoResponse<'a>),
     /// Positive response to `RequestDownload`.
@@ -74,7 +75,9 @@ impl<'a> Decode<'a> for Response<'a> {
         let payload = &buf[1..];
 
         let response = match service {
-            UdsServiceType::ClearDiagnosticInfo => Self::ClearDiagnosticInfo,
+            UdsServiceType::ClearDiagnosticInfo => Self::ClearDiagnosticInfo(
+                <ClearDiagnosticInfoResponse as Decode>::decode_exact(payload)?,
+            ),
             UdsServiceType::CommunicationControl => Self::CommunicationControl(
                 <CommunicationControlResponse as Decode>::decode_exact(payload)?,
             ),
@@ -90,7 +93,9 @@ impl<'a> Decode<'a> for Response<'a> {
             UdsServiceType::NegativeResponse => {
                 Self::NegativeResponse(<NegativeResponse as Decode>::decode_exact(payload)?)
             }
-            UdsServiceType::ReadDataByIdentifier => Self::ReadDataByIdentifier(payload),
+            UdsServiceType::ReadDataByIdentifier => {
+                Self::ReadDataByIdentifier(ReadDataByIdentifierResponse::new(payload))
+            }
             UdsServiceType::ReadDTCInfo => {
                 Self::ReadDTCInfo(<ReadDTCInfoResponse as Decode>::decode_exact(payload)?)
             }
@@ -143,7 +148,7 @@ impl Response<'_> {
     /// Returns the response service-ID byte that frames this response on the wire.
     fn response_sid(&self) -> u8 {
         match self {
-            Self::ClearDiagnosticInfo => UdsServiceType::ClearDiagnosticInfo.response_to_byte(),
+            Self::ClearDiagnosticInfo(_) => UdsServiceType::ClearDiagnosticInfo.response_to_byte(),
             Self::CommunicationControl(_) => {
                 UdsServiceType::CommunicationControl.response_to_byte()
             }
@@ -175,15 +180,15 @@ impl Response<'_> {
 impl Encode for Response<'_> {
     fn encoded_size(&self) -> usize {
         let payload = match self {
-            Self::ClearDiagnosticInfo => 0,
+            Self::ClearDiagnosticInfo(resp) => resp.encoded_size(),
             Self::RequestTransferExit(resp) => resp.encoded_size(),
             Self::Other { data, .. } => data.len(),
             Self::CommunicationControl(resp) => resp.encoded_size(),
             Self::ControlDTCSettings(resp) => resp.encoded_size(),
             Self::DiagnosticSessionControl(resp) => resp.encoded_size(),
             Self::EcuReset(resp) => resp.encoded_size(),
             Self::NegativeResponse(resp) => resp.encoded_size(),
-            Self::ReadDataByIdentifier(bytes) => bytes.len(),
+            Self::ReadDataByIdentifier(resp) => resp.encoded_size(),
             Self::WriteDataByIdentifier(resp) => resp.encoded_size(),
             Self::ReadDTCInfo(resp) => resp.encoded_size(),
             Self::RequestDownload(resp) => resp.encoded_size(),
@@ -201,17 +206,14 @@ impl Encode for Response<'_> {
             .write_all(&[self.response_sid()])
             .map_err(Error::io)?;
         let payload = match self {
-            Self::ClearDiagnosticInfo => 0,
+            Self::ClearDiagnosticInfo(resp) => resp.encode(writer)?,
             Self::RequestTransferExit(resp) => resp.encode(writer)?,
             Self::CommunicationControl(resp) => resp.encode(writer)?,
             Self::ControlDTCSettings(resp) => resp.encode(writer)?,
             Self::DiagnosticSessionControl(resp) => resp.encode(writer)?,
             Self::EcuReset(resp) => resp.encode(writer)?,
             Self::NegativeResponse(resp) => resp.encode(writer)?,
-            Self::ReadDataByIdentifier(bytes) => {
-                writer.write_all(bytes).map_err(Error::io)?;
-                bytes.len()
-            }
+            Self::ReadDataByIdentifier(resp) => resp.encode(writer)?,
             Self::WriteDataByIdentifier(resp) => resp.encode(writer)?,
             Self::ReadDTCInfo(resp) => resp.encode(writer)?,
             Self::RequestDownload(resp) => resp.encode(writer)?,
@@ -284,4 +286,17 @@ mod tests {
         let written = Encode::encode(&resp, &mut buf.as_mut_slice()).unwrap();
         assert_eq!(&buf[..written], &frame); // previously became 0x7F (NegativeResponse)
     }
+
+    #[test]
+    fn clear_diagnostic_info_response_rejects_trailing_bytes() {
+        // Bare SID round-trips; a conformant ClearDiagnosticInfo positive response is [0x54].
+        let (resp, remaining) = Response::decode(&[0x54]).unwrap();
+        assert!(remaining.is_empty());
+        assert!(matches!(resp, Response::ClearDiagnosticInfo(_)));
+        // Trailing bytes after the SID are now rejected (matches every other response arm).
+        assert!(matches!(
+            Response::decode(&[0x54, 0xAA]),
+            Err(crate::Error::IncorrectMessageLengthOrInvalidFormat)
+        ));
+    }
 }

src/services/clear_dtc_information.rs

@@ -1,6 +1,38 @@
 //! `ClearDiagnosticInformation` (0x14) service implementation
 use crate::{CLEAR_ALL_DTCS, DTCRecord, Decode, Encode, NegativeResponseCode};
 
+/// Positive response to `ClearDiagnosticInformation`. Carries no payload.
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
+#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
+#[non_exhaustive]
+pub struct ClearDiagnosticInfoResponse;
+
+impl ClearDiagnosticInfoResponse {
+    /// Create a `ClearDiagnosticInfoResponse`.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self
+    }
+}
+
+impl Encode for ClearDiagnosticInfoResponse {
+    fn encoded_size(&self) -> usize {
+        0
+    }
+    fn encode(&self, _writer: &mut impl embedded_io::Write) -> Result<usize, crate::Error> {
+        Ok(0)
+    }
+}
+
+impl<'a> Decode<'a> for ClearDiagnosticInfoResponse {
+    /// Consumes zero bytes and returns the full buffer as the remainder.
+    /// `decode_exact` at the call site (in `Response::decode`) enforces that no trailing bytes follow the SID.
+    fn decode(buf: &'a [u8]) -> Result<(Self, &'a [u8]), crate::Error> {
+        Ok((Self, buf))
+    }
+}
+
 /// Negative response codes
 const CLEAR_DIAG_INFO_NEGATIVE_RESPONSE_CODES: [NegativeResponseCode; 4] = [
     NegativeResponseCode::IncorrectMessageLengthOrInvalidFormat,
@@ -108,3 +140,21 @@ mod request {
         assert_eq!(all, compare);
     }
 }
+
+#[cfg(test)]
+mod response {
+    use super::*;
+    use crate::{Decode, Encode};
+
+    #[test]
+    fn clear_dtc_response_roundtrips_empty() {
+        let resp = ClearDiagnosticInfoResponse::new();
+        let mut buf = [0u8; 4];
+        let n = Encode::encode(&resp, &mut buf.as_mut_slice()).unwrap();
+        assert_eq!(n, 0);
+        let (decoded, remaining) =
+            <ClearDiagnosticInfoResponse as Decode>::decode(&buf[..0]).unwrap();
+        assert_eq!(decoded, resp);
+        assert!(remaining.is_empty());
+    }
+}

src/services/control_dtc_settings.rs

@@ -1,6 +1,6 @@
 //! `ControlDTCSetting` (0x85) service implementation
 use crate::shared::SuppressablePositiveResponse;
-use crate::{Decode, Encode, Error};
+use crate::{Decode, Encode, Error, NegativeResponseCode};
 
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
@@ -49,6 +49,13 @@ pub struct ControlDTCSettingsRequest {
     pub setting: DtcSettings,
 }
 
+const CONTROL_DTC_SETTINGS_NEGATIVE_RESPONSE_CODES: [NegativeResponseCode; 4] = [
+    NegativeResponseCode::SubFunctionNotSupported,
+    NegativeResponseCode::IncorrectMessageLengthOrInvalidFormat,
+    NegativeResponseCode::ConditionsNotCorrect,
+    NegativeResponseCode::RequestOutOfRange,
+];
+
 impl ControlDTCSettingsRequest {
     /// Create a new `ControlDTCSettingsRequest`.
     #[must_use]
@@ -58,6 +65,12 @@ impl ControlDTCSettingsRequest {
             setting,
         }
     }
+
+    /// Get the allowed [`NegativeResponseCode`] variants for this request.
+    #[must_use]
+    pub fn allowed_nack_codes() -> &'static [NegativeResponseCode] {
+        &CONTROL_DTC_SETTINGS_NEGATIVE_RESPONSE_CODES
+    }
 }
 
 impl Encode for ControlDTCSettingsRequest {
@@ -96,7 +109,7 @@ impl<'a> Decode<'a> for ControlDTCSettingsRequest {
 /// The ECU will respond with a `ControlDTCSettingsResponse` if the request was successful.
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "utoipa", derive(utoipa::ToSchema))]
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 #[non_exhaustive]
 pub struct ControlDTCSettingsResponse {
     /// The DTC logging setting that was set in the request
@@ -137,7 +150,7 @@ impl<'a> Decode<'a> for ControlDTCSettingsResponse {
 #[cfg(test)]
 mod request {
     use super::*;
-    use crate::{Decode, Encode, test_util::assert_encode_size_agrees};
+    use crate::{Decode, Encode, NegativeResponseCode, test_util::assert_encode_size_agrees};
     #[cfg(feature = "alloc")]
     use alloc::{vec, vec::Vec};
 
@@ -164,6 +177,15 @@ mod request {
         let err = <ControlDTCSettingsRequest as Decode>::decode(&[0x09]).unwrap_err();
         assert!(matches!(err, Error::InvalidDtcSetting(0x09)));
     }
+
+    #[test]
+    fn exposes_allowed_nack_codes() {
+        assert!(!ControlDTCSettingsRequest::allowed_nack_codes().is_empty());
+        assert!(
+            ControlDTCSettingsRequest::allowed_nack_codes()
+                .contains(&NegativeResponseCode::RequestOutOfRange)
+        );
+    }
 }
 
 #[cfg(test)]
@@ -187,4 +209,9 @@ mod response {
         assert_eq!(parsed.setting, DtcSettings::On);
         assert_encode_size_agrees(&req);
     }
+
+    #[test]
+    fn response_is_eq() {
+        crate::test_util::assert_impl_eq::<ControlDTCSettingsResponse>();
+    }
 }

src/services/mod.rs

@@ -1,5 +1,5 @@
 mod clear_dtc_information;
-pub use clear_dtc_information::ClearDiagnosticInfoRequest;
+pub use clear_dtc_information::{ClearDiagnosticInfoRequest, ClearDiagnosticInfoResponse};
 
 mod communication_control;
 pub use communication_control::{
@@ -24,7 +24,7 @@ mod negative_response;
 pub use negative_response::NegativeResponse;
 
 mod read_data_by_identifier;
-pub use read_data_by_identifier::ReadDataByIdentifierRequest;
+pub use read_data_by_identifier::{ReadDataByIdentifierRequest, ReadDataByIdentifierResponse};
 
 mod read_dtc_information;
 pub use read_dtc_information::{