4 files changed, 89 insertions, 8 deletions
diff --git a/vendor/github.com/uptrace/bun/schema/field.go b/vendor/github.com/uptrace/bun/schema/field.go
index 06d0a5094..09949dd72 100644
--- a/vendor/github.com/uptrace/bun/schema/field.go
+++ b/vendor/github.com/uptrace/bun/schema/field.go
@@ -10,6 +10,7 @@ import (
 )
 
 type Field struct {
+	Table       *Table // Contains this field
 	StructField reflect.StructField
 	IsPtr       bool
 
diff --git a/vendor/github.com/uptrace/bun/schema/relation.go b/vendor/github.com/uptrace/bun/schema/relation.go
index f653cd7a3..0711635f5 100644
--- a/vendor/github.com/uptrace/bun/schema/relation.go
+++ b/vendor/github.com/uptrace/bun/schema/relation.go
@@ -13,12 +13,12 @@ const (
 )
 
 type Relation struct {
+	Type  int
+	Field *Field // Has the bun tag defining this relation.
+
 	// Base and Join can be explained with this query:
 	//
 	// SELECT * FROM base_table JOIN join_table
-
-	Type      int
-	Field     *Field
 	JoinTable *Table
 	BasePKs   []*Field
 	JoinPKs   []*Field
@@ -34,10 +34,49 @@ type Relation struct {
 	M2MJoinPKs []*Field
 }
 
-// References returns true if the table to which the Relation belongs needs to declare a foreign key constraint to create the relation.
-// For other relations, the constraint is created in either the referencing table (1:N, 'has-many' relations) or a mapping table (N:N, 'm2m' relations).
+// References returns true if the table which defines this Relation
+// needs to declare a foreign key constraint, as is the case
+// for 'has-one' and 'belongs-to' relations. For other relations,
+// the constraint is created either in the referencing table (1:N, 'has-many' relations)
+// or the junction table (N:N, 'm2m' relations).
+//
+// Usage of `rel:` tag does not always imply creation of foreign keys (when WithForeignKeys() is not set)
+// and can be used exclusively for joining tables at query time. For example:
+//
+//	type User struct {
+//		ID int64			`bun:",pk"`
+//		Profile *Profile	`bun:",rel:has-one,join:id=user_id"`
+//	}
+//
+// Creating a FK users.id -> profiles.user_id would be confusing and incorrect,
+// so for such cases References() returns false. One notable exception to this rule
+// is when a Relation is defined in a junction table, in which case it is perfectly
+// fine for its primary keys to reference other tables. Consider:
+//
+//	// UsersToGroups maps users to groups they follow.
+//	type UsersToGroups struct {
+//		UserID string	`bun:"user_id,pk"`		// Needs FK to users.id
+//		GroupID string	`bun:"group_id,pk"`		// Needs FK to groups.id
+//
+//		User	*User	`bun:"rel:belongs-to,join:user_id=id"`
+//		Group	*Group	`bun:"rel:belongs-to,join:group_id=id"`
+//	}
+//
+// Here BooksToReaders has a composite primary key, composed of other primary keys.
 func (r *Relation) References() bool {
-	return r.Type == HasOneRelation || r.Type == BelongsToRelation
+	allPK := true
+	nonePK := true
+	for _, f := range r.BasePKs {
+		allPK = allPK && f.IsPK
+		nonePK = nonePK && !f.IsPK
+	}
+
+	// Erring on the side of caution, only create foreign keys
+	// if the referencing columns are part of a composite PK
+	// in the junction table of the m2m relationship.
+	effectsM2M := r.Field.Table.IsM2MTable && allPK
+
+	return (r.Type == HasOneRelation || r.Type == BelongsToRelation) && (effectsM2M || nonePK)
 }
 
 func (r *Relation) String() string {
diff --git a/vendor/github.com/uptrace/bun/schema/sqlfmt.go b/vendor/github.com/uptrace/bun/schema/sqlfmt.go
index 7b4a9493f..5a9d70460 100644
--- a/vendor/github.com/uptrace/bun/schema/sqlfmt.go
+++ b/vendor/github.com/uptrace/bun/schema/sqlfmt.go
@@ -50,6 +50,7 @@ func (s Ident) AppendQuery(fmter Formatter, b []byte) ([]byte, error) {
 
 //------------------------------------------------------------------------------
 
+// NOTE: It should not be modified after creation.
 type QueryWithArgs struct {
 	Query string
 	Args  []interface{}
diff --git a/vendor/github.com/uptrace/bun/schema/table.go b/vendor/github.com/uptrace/bun/schema/table.go
index 13b989e4d..cf9f49197 100644
--- a/vendor/github.com/uptrace/bun/schema/table.go
+++ b/vendor/github.com/uptrace/bun/schema/table.go
@@ -62,8 +62,9 @@ type Table struct {
 	FieldMap  map[string]*Field
 	StructMap map[string]*structField
 
-	Relations map[string]*Relation
-	Unique    map[string][]*Field
+	IsM2MTable bool // If true, this table is the "junction table" of an m2m relation.
+	Relations  map[string]*Relation
+	Unique     map[string][]*Field
 
 	SoftDeleteField       *Field
 	UpdateSoftDeleteField func(fv reflect.Value, tm time.Time) error
@@ -122,6 +123,7 @@ func (t *Table) processFields(typ reflect.Type) {
 
 	names := make(map[string]struct{})
 	embedded := make([]embeddedField, 0, 10)
+	ebdStructs := make(map[string]*structField, 0)
 
 	for i, n := 0, typ.NumField(); i < n; i++ {
 		sf := typ.Field(i)
@@ -163,6 +165,17 @@ func (t *Table) processFields(typ reflect.Type) {
 					subfield:   subfield,
 				})
 			}
+			if len(subtable.StructMap) > 0 {
+				for k, v := range subtable.StructMap {
+					// NOTE: conflict Struct name
+					if _, ok := ebdStructs[k]; !ok {
+						ebdStructs[k] = &structField{
+							Index: makeIndex(sf.Index, v.Index),
+							Table: subtable,
+						}
+					}
+				}
+			}
 
 			if tagstr != "" {
 				tag := tagparser.Parse(tagstr)
@@ -197,6 +210,18 @@ func (t *Table) processFields(typ reflect.Type) {
 					subfield:   subfield,
 				})
 			}
+			if len(subtable.StructMap) > 0 {
+				for k, v := range subtable.StructMap {
+					// NOTE: conflict Struct name
+					k = prefix + k
+					if _, ok := ebdStructs[k]; !ok {
+						ebdStructs[k] = &structField{
+							Index: makeIndex(sf.Index, v.Index),
+							Table: subtable,
+						}
+					}
+				}
+			}
 			continue
 		}
 
@@ -252,6 +277,15 @@ func (t *Table) processFields(typ reflect.Type) {
 		}
 	}
 
+	if len(ebdStructs) > 0 && t.StructMap == nil {
+		t.StructMap = make(map[string]*structField)
+	}
+	for name, sfield := range ebdStructs {
+		if _, ok := t.StructMap[name]; !ok {
+			t.StructMap[name] = sfield
+		}
+	}
+
 	if len(embedded) > 0 {
 		// https://github.com/uptrace/bun/issues/1095
 		// < v1.2, all fields follow the order corresponding to the struct
@@ -483,6 +517,7 @@ func (t *Table) newField(sf reflect.StructField, tag tagparser.Tag) *Field {
 	}
 
 	field := &Field{
+		Table:       t,
 		StructField: sf,
 		IsPtr:       sf.Type.Kind() == reflect.Ptr,
 
@@ -862,6 +897,7 @@ func (t *Table) m2mRelation(field *Field) *Relation {
 		JoinTable: joinTable,
 		M2MTable:  m2mTable,
 	}
+	m2mTable.markM2M()
 
 	if field.Tag.HasOption("join_on") {
 		rel.Condition = field.Tag.Options["join_on"]
@@ -907,6 +943,10 @@ func (t *Table) m2mRelation(field *Field) *Relation {
 	return rel
 }
 
+func (t *Table) markM2M() {
+	t.IsM2MTable = true
+}
+
 //------------------------------------------------------------------------------
 
 func (t *Table) Dialect() Dialect { return t.dialect }