From 1c9346872f922c2f66e4e0b3396380f25cbb447a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luismi=20Cavall=C3=A9?= <luismi@lmcavalle.com>
Date: Fri, 11 Oct 2024 07:22:24 +0000
Subject: [PATCH] Fix panic when normalizing certain invoices in MX

---
 CHANGELOG.md               |  6 ++++++
 regimes/mx/invoice.go      |  2 +-
 regimes/mx/invoice_test.go | 10 ++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04e8a4be..ce59eb00 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,12 @@ All notable changes to GOBL will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this project adheres to [Semantic Versioning](http://semver.org/). See also the [GOBL versions](https://docs.gobl.org/overview/versions) documentation site for more details.
 
+## [v0.201.1]
+
+### Fixed
+
+- `mx`: fixed panic when normalizing an invoice with `tax` but no `ext` inside.
+
 ## [v0.201.0]
 
 ### Fixed
diff --git a/regimes/mx/invoice.go b/regimes/mx/invoice.go
index c7a92bdb..9698ee3e 100644
--- a/regimes/mx/invoice.go
+++ b/regimes/mx/invoice.go
@@ -17,7 +17,7 @@ func normalizeInvoice(inv *bill.Invoice) {
 	// set.
 	normalizeParty(inv.Supplier) // first do party
 	ext := make(tax.Extensions)
-	if inv.Tax != nil {
+	if inv.Tax != nil && inv.Tax.Ext != nil {
 		ext = inv.Tax.Ext
 	}
 	if ext.Has(extKeyIssuePlace) {
diff --git a/regimes/mx/invoice_test.go b/regimes/mx/invoice_test.go
index c0223988..5ffd1c07 100644
--- a/regimes/mx/invoice_test.go
+++ b/regimes/mx/invoice_test.go
@@ -21,6 +21,16 @@ func TestNormalizeInvoice(t *testing.T) {
 		require.NotNil(t, inv.Tax)
 		assert.Equal(t, tax.ExtValue("21000"), inv.Tax.Ext[cfdi.ExtKeyIssuePlace])
 	})
+
+	t.Run("no ext", func(t *testing.T) {
+		inv := baseInvoice()
+		inv.Tax = &bill.Tax{}
+		require.NoError(t, inv.Calculate())
+		require.NoError(t, inv.Validate())
+		require.NotNil(t, inv.Tax)
+		assert.Equal(t, tax.ExtValue("21000"), inv.Tax.Ext[cfdi.ExtKeyIssuePlace])
+	})
+
 	t.Run("with supplier address code", func(t *testing.T) {
 		inv := baseInvoice()
 		delete(inv.Supplier.Ext, cfdi.ExtKeyPostCode)