Errors

Every failure the library throws is an NFCError. It is Sendable, Equatable and a LocalizedError with localized descriptions, so apps can match on cases instead of message text.

Cancellation

do {
    let (info, dump) = try await CoreExtendedNFC.scanAndDump()
} catch where error.isNFCCancellation {
    // User dismissed the sheet, task cancelled, or the app ended the scan: stay silent.
} catch {
    showAlert(error.localizedDescription)
}

Error.isNFCCancellation is true for NFCError.userCanceled, CancellationError and NFCError.sessionInvalidatedByCaller. NFCError.isUserCancellation is true only for .userCanceled. After the user dismisses the sheet, later session-loss failures from that session's transports are reported as .userCanceled. NFCSessionManager.wasCanceledByUser covers a failure that raced the cancel.

Cases

Case	Meaning
`nfcNotAvailable`	The device has no NFC tag reading.
`sessionTimeout`	The reader session hit the system time limit.
`tagConnectionLost`	The tag left the field or stopped answering.
`tagNotSupported`	No flow exists for this card: no dump flow, no NDEF path, NDEF formatting on Type 3/4, or a transit card no reader recognizes.
`sessionInvalidated(String)`	The session ended for a reason without a dedicated case; the text is the system's description.
`userCanceled`	The user dismissed the NFC sheet.
`systemBusy`	Another reader session holds the NFC hardware.
`sessionInvalidatedByCaller`	The app ended a pending scan with `invalidate()` or `invalidate(errorMessage:)`.
`scanInProgress`	`scan` was called while another scan on the same `NFCSessionManager` was still waiting for a tag.
`crcMismatch`	A tag response failed its RF frame CRC.
`checksumMismatch`	A checksum carried in card data did not match, for example the Type 3 Tag Attribute Information Block.
`invalidResponse(Data)`	The tag's response was malformed or too short.
`unexpectedStatusWord(UInt8, UInt8)`	An ISO 7816 status word the operation does not accept.
`responseChainTooLong(maxFrames:)`	The card kept asking for more response frames (`61xx`, `91AF`) past the limit.
`applicationNotFound(aid:)`	SELECT by AID was answered with "not found" (`6A82`, `6A86`, `6999`, ...). See `ResponseAPDU.isApplicationNotFound`.
`iso15693Error(code:)`	An ISO 15693 error code other than `0x12` / `0x14` (block locked), for example `0x10` block not available.
`authenticationFailed`	Authentication with the tag failed.
`pinVerificationFailed(remainingAttempts:)`	VERIFY was refused or the PIN is blocked; `0` when blocked, `nil` when the card did not say.
`pinRequired(MyNumberPINType)`	The operation needs this PIN but none was supplied.
`writeFailed(page:)`	The tag did not acknowledge a page write.
`tagLocked`	The tag or block denies writing: Type 2/4/5 CC write access, a Type 3 Attribute Information Block whose RWFlag is not `01h`, ISO 15693 codes `0x12` / `0x14`, Type 4 UPDATE BINARY `6982` / `6985`.
`irreversibleWriteRefused(page:)`	A write to a lock, OTP, configuration, password or key page was refused before anything was sent, because the caller did not pass `allowIrreversible: true`.
`tagNotNDEFFormatted`	No NDEF Capability Container or NDEF Tag Application; format the tag first.
`ndefMessageNotFound`	The tag is NDEF formatted but holds no NDEF message, or only an empty one (for example after erasing it with `writeNDEF` and no records). Raised on every NDEF family.
`ndefCapacityExceeded(required:capacity:)`	The encoded message does not fit the tag's NDEF area.
`desfireError(DESFireStatus)`	A DESFire native status other than success.
`felicaBlockReadFailed(statusFlag:)` / `felicaBlockWriteFailed(statusFlag:)`	A FeliCa block command returned a non-zero status flag.
`bacFailed(String)`	BAC or the plain eMRTD application SELECT before BAC failed.
`secureMessagingError(String)`	Secure Messaging or PACE failed, or the chip refused the protected eMRTD application SELECT after PACE with a protected status (a plain status word surfaces as `unexpectedStatusWord`).
`dataGroupNotAvailable(String)` / `dataGroupParseFailed(String)`	An eMRTD file is absent or protected, or could not be parsed.
`cryptoError(String)`	A cryptographic operation failed.
`notOperableOnIOS(CardType)`	iOS cannot operate this card type, for example MIFARE Classic.
`unsupportedOperation(String)`	The operation does not apply to this transport or card, or the library refused it.
`invalidParameter(String)`	An argument is out of range or malformed, for example a DESFire AID that is not 3 bytes.
`malformedDump(String)`	A memory dump being exported or imported is malformed or inconsistent.