From f42f4a278600b2c26c14d65997dd762fe39541a7 Mon Sep 17 00:00:00 2001
From: Sasha Mitchell <sash.t.mitchell@gmail.com>
Date: Sat, 26 Sep 2026 12:51:06 +0700
Subject: [PATCH] Keep significant zeros in the NFC-e CSC id.

SEFAZ drops only non-significant zeros. Removing every zero turned id 100 into 1, so the QR hash was for the wrong token.
---
 pynfe/processamento/serializacao.py |  5 ++-
 tests/test_nfce_qrcode_csc.py       | 62 +++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 2 deletions(-)
 create mode 100644 tests/test_nfce_qrcode_csc.py

diff --git a/pynfe/processamento/serializacao.py b/pynfe/processamento/serializacao.py
index cb463000..4862970d 100644
--- a/pynfe/processamento/serializacao.py
+++ b/pynfe/processamento/serializacao.py
@@ -2144,8 +2144,9 @@ def gerar_qrcode(self, token, csc, xml, return_qr=False, online=True):
         lista_dia = re.findall(r"-\d{2}", str(data))
         dia = str(lista_dia[1])
         dia = dia[1:]
-        replacements = {"0": ""}
-        token = re.sub("([0])", lambda m: replacements[m.group()], token)
+        # Id do CSC sem zeros nao significativos (a esquerda). Um zero que
+        # faz parte do identificador, como em 000100, permanece.
+        token = token.lstrip("0")
 
         # VERSAO_QRCODE =2
         if online:
diff --git a/tests/test_nfce_qrcode_csc.py b/tests/test_nfce_qrcode_csc.py
new file mode 100644
index 00000000..0e063128
--- /dev/null
+++ b/tests/test_nfce_qrcode_csc.py
@@ -0,0 +1,62 @@
+import hashlib
+import unittest
+
+from lxml import etree
+
+from pynfe.processamento.serializacao import SerializacaoQrcode
+from pynfe.utils.flags import NAMESPACE_NFE, NAMESPACE_SIG, VERSAO_QRCODE
+from pynfe.utils.webservices import NFCE
+
+CHAVE = "4" * 44
+CSC = "CSC-TEST-SECRET"
+
+
+def _tag(namespace, name):
+    return f"{{{namespace}}}{name}"
+
+
+def _nota(chave=CHAVE):
+    nfe = etree.Element(_tag(NAMESPACE_NFE, "NFe"), nsmap={None: NAMESPACE_NFE})
+    inf = etree.SubElement(nfe, _tag(NAMESPACE_NFE, "infNFe"))
+    inf.set("Id", "NFe" + chave)
+    ide = etree.SubElement(inf, _tag(NAMESPACE_NFE, "ide"))
+    etree.SubElement(ide, _tag(NAMESPACE_NFE, "cUF")).text = "41"
+    etree.SubElement(ide, _tag(NAMESPACE_NFE, "dhEmi")).text = "2024-01-15T10:00:00-03:00"
+    etree.SubElement(ide, _tag(NAMESPACE_NFE, "tpAmb")).text = "1"
+    total = etree.SubElement(inf, _tag(NAMESPACE_NFE, "total"))
+    icms = etree.SubElement(total, _tag(NAMESPACE_NFE, "ICMSTot"))
+    etree.SubElement(icms, _tag(NAMESPACE_NFE, "vNF")).text = "10.00"
+    signature = etree.SubElement(nfe, _tag(NAMESPACE_SIG, "Signature"))
+    signed = etree.SubElement(signature, _tag(NAMESPACE_SIG, "SignedInfo"))
+    reference = etree.SubElement(signed, _tag(NAMESPACE_SIG, "Reference"))
+    etree.SubElement(reference, _tag(NAMESPACE_SIG, "DigestValue")).text = "abc="
+    return nfe
+
+
+def _parametro(qrcode):
+    return qrcode.split("p=", 1)[1]
+
+
+class NfceQrCodeCscTest(unittest.TestCase):
+    def test_id_do_csc_preserva_zero_significativo(self):
+        _, qrcode = SerializacaoQrcode().gerar_qrcode(
+            "000100", CSC, _nota(), return_qr=True, online=True
+        )
+        parametro = _parametro(qrcode)
+        campos = parametro.split("|")
+        self.assertEqual(campos[3], "100")
+        payload = "|".join(campos[:4])
+        esperado = hashlib.sha1((payload + CSC).encode()).hexdigest().upper()
+        self.assertEqual(campos[4], esperado)
+        self.assertTrue(qrcode.startswith(NFCE["PR"]["QR"]))
+        self.assertEqual(campos[1], VERSAO_QRCODE)
+
+    def test_id_do_csc_remove_apenas_zeros_a_esquerda(self):
+        _, qrcode = SerializacaoQrcode().gerar_qrcode(
+            "000001", CSC, _nota(), return_qr=True, online=True
+        )
+        self.assertEqual(_parametro(qrcode).split("|")[3], "1")
+
+
+if __name__ == "__main__":
+    unittest.main()