From 60450d09d0f4a86f87cfb3029a0a707a0e3417e5 Mon Sep 17 00:00:00 2001
From: Thomas Maroschik <tmaroschik@dfau.de>
Date: Mon, 8 Jan 2024 14:47:36 +0100
Subject: [PATCH 1/2] fix(pdns): provider implicitly changes CNAME to ALIAS

Fixes: https://github.com/kubernetes-sigs/external-dns/issues/3970
---
 provider/pdns/pdns.go      |  8 ++--
 provider/pdns/pdns_test.go | 77 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 3 deletions(-)

diff --git a/provider/pdns/pdns.go b/provider/pdns/pdns.go
index 1c83a091e4..771dfaf690 100644
--- a/provider/pdns/pdns.go
+++ b/provider/pdns/pdns.go
@@ -316,12 +316,14 @@ func (p *PDNSProvider) ConvertEndpointsToZones(eps []*endpoint.Endpoint, changet
 				for _, t := range ep.Targets {
 					if ep.RecordType == "CNAME" || ep.RecordType == "ALIAS" {
 						t = provider.EnsureTrailingDot(t)
-						if t != zone.Name && !strings.HasSuffix(t, "."+zone.Name) {
-							RecordType_ = "ALIAS"
-						}
 					}
 					records = append(records, pgo.Record{Content: t})
 				}
+
+				if dnsname == zone.Name && ep.RecordType == "CNAME" {
+					RecordType_ = "ALIAS"
+				}
+
 				rrset := pgo.RrSet{
 					Name:       dnsname,
 					Type_:      RecordType_,
diff --git a/provider/pdns/pdns_test.go b/provider/pdns/pdns_test.go
index 2837ef81ee..01489da9c7 100644
--- a/provider/pdns/pdns_test.go
+++ b/provider/pdns/pdns_test.go
@@ -178,6 +178,12 @@ var (
 		endpoint.NewEndpointWithTTL("test.simexample.com", endpoint.RecordTypeA, endpoint.TTL(300), "9.9.9.9"),
 		endpoint.NewEndpointWithTTL("test.simexample.com", endpoint.RecordTypeTXT, endpoint.TTL(300), "\"heritage=external-dns,external-dns/owner=tower-pdns\""),
 	}
+	endpointsApexRecords = []*endpoint.Endpoint{
+		endpoint.NewEndpointWithTTL("cname.example.com", endpoint.RecordTypeTXT, endpoint.TTL(300), "\"heritage=external-dns,external-dns/owner=tower-pdns\""),
+		endpoint.NewEndpointWithTTL("cname.example.com", endpoint.RecordTypeCNAME, endpoint.TTL(300), "example.by.any.other.name.com"),
+		endpoint.NewEndpointWithTTL("example.com", endpoint.RecordTypeTXT, endpoint.TTL(300), "\"heritage=external-dns,external-dns/owner=tower-pdns\""),
+		endpoint.NewEndpointWithTTL("example.com", endpoint.RecordTypeCNAME, endpoint.TTL(300), "example.by.any.other.name.com"),
+	}
 
 	ZoneEmpty = pgo.Zone{
 		// Opaque zone id (string), assigned by the server, should not be interpreted by the application. Guaranteed to be safe for embedding in URLs.
@@ -484,6 +490,72 @@ var (
 		},
 	}
 
+	ZoneEmptyToApexPatch = pgo.Zone{
+		Id:    "example.com.",
+		Name:  "example.com.",
+		Type_: "Zone",
+		Url:   "/api/v1/servers/localhost/zones/example.com.",
+		Kind:  "Native",
+		Rrsets: []pgo.RrSet{
+			{
+				Name:       "cname.example.com.",
+				Type_:      "CNAME",
+				Ttl:        300,
+				Changetype: "REPLACE",
+				Records: []pgo.Record{
+					{
+						Content:  "example.by.any.other.name.com.",
+						Disabled: false,
+						SetPtr:   false,
+					},
+				},
+				Comments: []pgo.Comment(nil),
+			},
+			{
+				Name:       "cname.example.com.",
+				Type_:      "TXT",
+				Ttl:        300,
+				Changetype: "REPLACE",
+				Records: []pgo.Record{
+					{
+						Content:  "\"heritage=external-dns,external-dns/owner=tower-pdns\"",
+						Disabled: false,
+						SetPtr:   false,
+					},
+				},
+				Comments: []pgo.Comment(nil),
+			},
+			{
+				Name:       "example.com.",
+				Type_:      "ALIAS",
+				Ttl:        300,
+				Changetype: "REPLACE",
+				Records: []pgo.Record{
+					{
+						Content:  "example.by.any.other.name.com.",
+						Disabled: false,
+						SetPtr:   false,
+					},
+				},
+				Comments: []pgo.Comment(nil),
+			},
+			{
+				Name:       "example.com.",
+				Type_:      "TXT",
+				Ttl:        300,
+				Changetype: "REPLACE",
+				Records: []pgo.Record{
+					{
+						Content:  "\"heritage=external-dns,external-dns/owner=tower-pdns\"",
+						Disabled: false,
+						SetPtr:   false,
+					},
+				},
+				Comments: []pgo.Comment(nil),
+			},
+		},
+	}
+
 	DomainFilterListSingle = endpoint.DomainFilter{
 		Filters: []string{
 			"example.com",
@@ -871,6 +943,11 @@ func (suite *NewPDNSProviderTestSuite) TestPDNSConvertEndpointsToZones() {
 			}
 		}
 	}
+
+	// Check endpoints of type CNAME are converted to ALIAS on the domain apex
+	zlist, err = p.ConvertEndpointsToZones(endpointsApexRecords, PdnsReplace)
+	assert.Nil(suite.T(), err)
+	assert.Equal(suite.T(), []pgo.Zone{ZoneEmptyToApexPatch}, zlist)
 }
 
 func (suite *NewPDNSProviderTestSuite) TestPDNSConvertEndpointsToZonesPartitionZones() {

From 99b7abda7e4949c1bedcd869bce8f8643963dce5 Mon Sep 17 00:00:00 2001
From: Thomas Maroschik <tmaroschik@dfau.de>
Date: Wed, 10 Jan 2024 16:51:09 +0100
Subject: [PATCH 2/2] feat: add debug message to CNAME to ALIAS conversion

Co-authored-by: Michel Loiseleur <97035654+mloiseleur@users.noreply.github.com>
---
 provider/pdns/pdns.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/provider/pdns/pdns.go b/provider/pdns/pdns.go
index 771dfaf690..fbc7cc22fa 100644
--- a/provider/pdns/pdns.go
+++ b/provider/pdns/pdns.go
@@ -321,6 +321,7 @@ func (p *PDNSProvider) ConvertEndpointsToZones(eps []*endpoint.Endpoint, changet
 				}
 
 				if dnsname == zone.Name && ep.RecordType == "CNAME" {
+					log.Debugf("Converting APEX record %s from CNAME to ALIAS", dnsname)
 					RecordType_ = "ALIAS"
 				}