From c4f84dcc843bdff1a5e01248b1edd231af0a5ef3 Mon Sep 17 00:00:00 2001
From: Andrew Sisley <a.j.sisley@hotmail.com>
Date: Wed, 27 Sep 2023 16:07:24 -0400
Subject: [PATCH] Ensure other field is returned from GetRelation

If the relationship references the same (host) collection, the function would in some circumstances return the known field.  In collection.save, when updating via a secondary one-one field this leads to an infinite loop.
---
 client/descriptions.go                             | 14 ++++++++------
 db/collection.go                                   |  2 +-
 db/collection_update.go                            |  7 ++++++-
 planner/type_join.go                               | 13 +++++++++++--
 .../field_kinds/one_to_one/with_self_ref_test.go   |  3 ---
 5 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/client/descriptions.go b/client/descriptions.go
index 0b44f36b83..f25fc40772 100644
--- a/client/descriptions.go
+++ b/client/descriptions.go
@@ -53,12 +53,14 @@ func (col CollectionDescription) GetFieldByID(id FieldID) (FieldDescription, boo
 }
 
 // GetRelation returns the field that supports the relation of the given name.
-func (col CollectionDescription) GetRelation(name string) (FieldDescription, bool) {
-	if !col.Schema.IsEmpty() {
-		for _, field := range col.Schema.Fields {
-			if field.RelationName == name {
-				return field, true
-			}
+func (col CollectionDescription) GetFieldByRelation(
+	relationName string,
+	otherCollectionName string,
+	otherFieldName string,
+) (FieldDescription, bool) {
+	for _, field := range col.Schema.Fields {
+		if field.RelationName == relationName && !(col.Name == otherCollectionName && otherFieldName == field.Name) {
+			return field, true
 		}
 	}
 	return FieldDescription{}, false
diff --git a/db/collection.go b/db/collection.go
index cda5cbf584..f5dacccfb1 100644
--- a/db/collection.go
+++ b/db/collection.go
@@ -1062,7 +1062,7 @@ func (c *collection) save(
 			if isSecondaryRelationID {
 				primaryId := val.Value().(string)
 
-				err = c.patchPrimaryDoc(ctx, txn, relationFieldDescription, primaryKey.DocKey, primaryId)
+				err = c.patchPrimaryDoc(ctx, txn, c.Name(), relationFieldDescription, primaryKey.DocKey, primaryId)
 				if err != nil {
 					return cid.Undef, err
 				}
diff --git a/db/collection_update.go b/db/collection_update.go
index 1a15482935..2e353dd0d3 100644
--- a/db/collection_update.go
+++ b/db/collection_update.go
@@ -350,6 +350,7 @@ func (c *collection) isSecondaryIDField(fieldDesc client.FieldDescription) (clie
 func (c *collection) patchPrimaryDoc(
 	ctx context.Context,
 	txn datastore.Txn,
+	secondaryCollectionName string,
 	relationFieldDescription client.FieldDescription,
 	docKey string,
 	fieldValue string,
@@ -365,7 +366,11 @@ func (c *collection) patchPrimaryDoc(
 	}
 	primaryCol = primaryCol.WithTxn(txn)
 
-	primaryField, ok := primaryCol.Description().GetRelation(relationFieldDescription.RelationName)
+	primaryField, ok := primaryCol.Description().GetFieldByRelation(
+		relationFieldDescription.RelationName,
+		secondaryCollectionName,
+		relationFieldDescription.Name,
+	)
 	if !ok {
 		return client.NewErrFieldNotExist(relationFieldDescription.RelationName)
 	}
diff --git a/planner/type_join.go b/planner/type_join.go
index f37437089e..ee771b01fc 100644
--- a/planner/type_join.go
+++ b/planner/type_join.go
@@ -259,7 +259,11 @@ func (p *Planner) makeTypeJoinOne(
 		return nil, err
 	}
 
-	subTypeField, subTypeFieldNameFound := subTypeCollectionDesc.GetRelation(subTypeFieldDesc.RelationName)
+	subTypeField, subTypeFieldNameFound := subTypeCollectionDesc.GetFieldByRelation(
+		subTypeFieldDesc.RelationName,
+		parent.sourceInfo.collectionDescription.Name,
+		subTypeFieldDesc.Name,
+	)
 	if !subTypeFieldNameFound {
 		return nil, client.NewErrFieldNotExist(subTypeFieldDesc.RelationName)
 	}
@@ -481,7 +485,12 @@ func (p *Planner) makeTypeJoinMany(
 		return nil, err
 	}
 
-	rootField, rootNameFound := subTypeCollectionDesc.GetRelation(subTypeFieldDesc.RelationName)
+	rootField, rootNameFound := subTypeCollectionDesc.GetFieldByRelation(
+		subTypeFieldDesc.RelationName,
+		parent.sourceInfo.collectionDescription.Name,
+		subTypeFieldDesc.Name,
+	)
+
 	if !rootNameFound {
 		return nil, client.NewErrFieldNotExist(subTypeFieldDesc.RelationName)
 	}
diff --git a/tests/integration/mutation/update/field_kinds/one_to_one/with_self_ref_test.go b/tests/integration/mutation/update/field_kinds/one_to_one/with_self_ref_test.go
index 9f95b91408..16225f4ab3 100644
--- a/tests/integration/mutation/update/field_kinds/one_to_one/with_self_ref_test.go
+++ b/tests/integration/mutation/update/field_kinds/one_to_one/with_self_ref_test.go
@@ -103,8 +103,6 @@ func TestMutationUpdateOneToOne_SelfReferencingFromPrimary(t *testing.T) {
 	testUtils.ExecuteTestCase(t, test)
 }
 
-/*
-This test will enter an infinite loop
 func TestMutationUpdateOneToOne_SelfReferencingFromSecondary(t *testing.T) {
 	user1ID := "bae-decf6467-4c7c-50d7-b09d-0a7097ef6bad"
 
@@ -191,4 +189,3 @@ func TestMutationUpdateOneToOne_SelfReferencingFromSecondary(t *testing.T) {
 
 	testUtils.ExecuteTestCase(t, test)
 }
-*/