feat: Add support for header comments in ORM-generated queries

orm/composite_create.go

@@ -53,6 +53,7 @@ func (q *CreateCompositeQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *CreateCompositeQuery) AppendQuery(fmter QueryFormatter, b []byte) ([]byte, error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/composite_drop.go

@@ -50,6 +50,7 @@ func (q *DropCompositeQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *DropCompositeQuery) AppendQuery(fmter QueryFormatter, b []byte) ([]byte, error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/delete.go

@@ -52,6 +52,7 @@ func (q *DeleteQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *DeleteQuery) AppendQuery(fmter QueryFormatter, b []byte) (_ []byte, err error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/insert.go

@@ -56,6 +56,7 @@ func (q *InsertQuery) AppendTemplate(b []byte) ([]byte, error) {
 var _ QueryAppender = (*InsertQuery)(nil)
 
 func (q *InsertQuery) AppendQuery(fmter QueryFormatter, b []byte) (_ []byte, err error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/query.go

@@ -81,6 +81,7 @@ type Query struct {
 
 	onConflict *SafeQueryAppender
 	returning  []*SafeQueryAppender
+	comment string
 }
 
 func NewQuery(db DB, model ...interface{}) *Query {
@@ -779,6 +780,12 @@ func (q *Query) Apply(fn func(*Query) (*Query, error)) *Query {
 	return qq
 }
 
+// Comment adds a comment to the query, wrapped by /* ... */.
+func (q *Query) Comment(c string) *Query {
+	q.comment = c
+	return q
+}
+
 // Count returns number of rows matching the query using count aggregate function.
 func (q *Query) Count() (int, error) {
 	if q.stickyErr != nil {

orm/select.go

@@ -53,6 +53,7 @@ func (q *SelectQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *SelectQuery) AppendQuery(fmter QueryFormatter, b []byte) (_ []byte, err error) { //nolint:gocyclo
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/table_create.go

@@ -64,6 +64,7 @@ func (q *CreateTableQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *CreateTableQuery) AppendQuery(fmter QueryFormatter, b []byte) (_ []byte, err error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/table_drop.go

@@ -50,6 +50,7 @@ func (q *DropTableQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *DropTableQuery) AppendQuery(fmter QueryFormatter, b []byte) (_ []byte, err error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/update.go

@@ -57,6 +57,7 @@ func (q *UpdateQuery) AppendTemplate(b []byte) ([]byte, error) {
 }
 
 func (q *UpdateQuery) AppendQuery(fmter QueryFormatter, b []byte) (_ []byte, err error) {
+	b = appendComment(b, q.q.comment)
 	if q.q.stickyErr != nil {
 		return nil, q.q.stickyErr
 	}

orm/util.go

@@ -1,7 +1,9 @@
 package orm
 
 import (
+	"fmt"
 	"reflect"
+	"strings"
 
 	"github.com/go-pg/pg/v10/types"
 )
@@ -149,3 +151,13 @@ func appendColumns(b []byte, table types.Safe, fields []*Field) []byte {
 	}
 	return b
 }
+
+// appendComment adds comment in the header of the query into buffer
+func appendComment(b []byte, name string) []byte {
+	if name == "" {
+		return b
+	}
+	name = strings.ReplaceAll(name, `/*`, `/\*`)
+	name = strings.ReplaceAll(name, `*/`, `*\/`)
+	return append(b, fmt.Sprintf("/* %s */ ", name)...)
+}

orm/util_test.go

@@ -0,0 +1,30 @@
+package orm
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Comment - escape comment symbols", func() {
+	It("only open sequence", func() {
+		var res []byte
+		c := "/* comment"
+
+		s := appendComment(res, c)
+		Expect(s).To(Equal([]byte("/* /\\* comment */ ")))
+	})
+	It("only close sequence", func() {
+		var res []byte
+		c := "comment */"
+
+		s := appendComment(res, c)
+		Expect(s).To(Equal([]byte("/* comment *\\/ */ ")))
+	})
+	It("open and close sequences", func() {
+		var res []byte
+		c := "/* comment */"
+
+		s := appendComment(res, c)
+		Expect(s).To(Equal([]byte("/* /\\* comment *\\/ */ ")))
+	})
+})