fix: make BIP21 URI scheme network-aware for BitcoinPurple

Adds BIP21_URI_SCHEME to AbstractNet (default 'bitcoin'), overridden
to 'btcp' in BitcoinPurple. All parse/create/scan paths now use
constants.net.BIP21_URI_SCHEME so QR codes with btcp:... URIs are
correctly recognised and generated on the Purple network.

electrum/bip21.py

@@ -5,12 +5,13 @@ from decimal import Decimal
 from typing import Optional
 
 from . import bitcoin
+from . import constants
 from .util import format_satoshis_plain
 from .bitcoin import COIN, TOTAL_COIN_SUPPLY_LIMIT_IN_BTC
 from .bolt11 import decode_bolt11_invoice, BOLT11DecodeException
 
 # note: when checking against these, use .lower() to support case-insensitivity
-BITCOIN_BIP21_URI_SCHEME = 'bitcoin'
+BITCOIN_BIP21_URI_SCHEME = 'bitcoin'  # kept for backward-compat imports
 LIGHTNING_URI_SCHEME = 'lightning'
 
 # note: URI scheme handler registrations are duplicated all over the codebase:
@@ -36,7 +37,7 @@ def parse_bip21_URI(uri: str) -> dict:
         return {'address': uri}
 
     u = urllib.parse.urlparse(uri)
-    if u.scheme.lower() != BITCOIN_BIP21_URI_SCHEME:
+    if u.scheme.lower() != constants.net.BIP21_URI_SCHEME:
         raise InvalidBitcoinURI("Not a bitcoin URI")
     address = u.path
 
@@ -127,7 +128,7 @@ def create_bip21_uri(addr, amount_sat: Optional[int], message: Optional[str],
         v = urllib.parse.quote(v)
         query.append(f"{k}={v}")
     p = urllib.parse.ParseResult(
-        scheme=BITCOIN_BIP21_URI_SCHEME,
+        scheme=constants.net.BIP21_URI_SCHEME,
         netloc='',
         path=addr,
         params='',

electrum/constants.py

@@ -83,6 +83,7 @@ class AbstractNet:
 
     COIN_SYMBOL: str = "BTC"
     COIN_NAME: str = "Bitcoin"
+    BIP21_URI_SCHEME: str = "bitcoin"
 
     # PoW difficulty parameters (Bitcoin defaults; override per chain as needed)
     DIFFICULTY_ADJUSTMENT_INTERVAL: int = 2016   # blocks per retarget window
@@ -283,6 +284,7 @@ class BitcoinPurple(AbstractNet):
     ADDRTYPE_P2SH = 55
     SEGWIT_HRP = "btcp"
     BOLT11_HRP = SEGWIT_HRP
+    BIP21_URI_SCHEME = "btcp"
     GENESIS = "000003823fbf82ea4906cbe214617ce7a70a5da29c19ecb1d65618bcf04ec015"
     DEFAULT_PORTS = {'t': '50001', 's': '50002'}
     BLOCK_HEIGHT_FIRST_LIGHTNING_CHANNELS = 0

electrum/gui/qml/qeqr.py

@@ -16,6 +16,7 @@ except ImportError:
     # Note: missing QtMultimedia will lead to errors when using QR scanner on desktop
     from PyQt6.QtCore import QObject as QVideoSink
 
+from electrum import constants
 from electrum.logging import get_logger
 from electrum.qrreader import get_qr_reader
 from electrum.i18n import _
@@ -144,7 +145,7 @@ class QEQRImageProvider(QQuickImageProvider):
         # (unknown schemes might be found when a colon is in a serialized TX, which
         # leads to mangling of the tx, so we check for supported schemes.)
         uri = urllib.parse.urlparse(qstr)
-        if uri.scheme and uri.scheme in ['bitcoin', 'lightning']:
+        if uri.scheme and uri.scheme in [constants.net.BIP21_URI_SCHEME, 'lightning']:
             # urlencode request parameters
             query = urllib.parse.parse_qs(uri.query)
             query = urllib.parse.urlencode(query, doseq=True, quote_via=urllib.parse.quote)

electrum/interface.py

@@ -1562,7 +1562,7 @@ class Interface(Logger):
             return ''
         if not isinstance(res, str):
             raise RequestCorrupted(f'{res!r} should be a str')
-        address = res.removeprefix('bitcoin:')
+        address = res.removeprefix(constants.net.BIP21_URI_SCHEME + ':')
         if not bitcoin.is_address(address):
             # note: do not hard-fail -- allow server to use future-type
             #       bitcoin address we do not recognize

electrum/invoices.py

@@ -341,7 +341,7 @@ class Request(BaseInvoice):
         if lightning_invoice:
             extra['lightning'] = lightning_invoice
         if not addr and lightning_invoice:
-            return "bitcoin:?lightning="+lightning_invoice
+            return f"{constants.net.BIP21_URI_SCHEME}:?lightning=" + lightning_invoice
         if not addr and not lightning_invoice:
             return None
         uri = create_bip21_uri(addr, amount, message, extra_query_params=extra)

electrum/payment_identifier.py

@@ -7,6 +7,7 @@ from enum import IntEnum
 from typing import NamedTuple, Optional, Callable, List, TYPE_CHECKING, Tuple, Union
 
 from . import bitcoin
+from . import constants
 from .contacts import AliasNotFoundException
 from .i18n import _
 from .invoices import Invoice
@@ -249,7 +250,7 @@ class PaymentIdentifier(Logger):
             self._type = PaymentIdentifierType.LNURL
             self.lnurl = lnurl_url
             self.set_state(PaymentIdentifierState.NEED_RESOLVE)
-        elif text.lower().startswith(BITCOIN_BIP21_URI_SCHEME + ':'):
+        elif text.lower().startswith(constants.net.BIP21_URI_SCHEME + ':'):
             try:
                 out = parse_bip21_URI(text)
             except InvalidBitcoinURI as e: