feat(golang): support custom enum type slices for pgx/v4 & pgx/v5

Author: toqueteos

examples/batch/postgresql/models.go

@@ -7,6 +7,7 @@ require (
 	github.com/bytecodealliance/wasmtime-go/v8 v8.0.0
 	github.com/cubicdaiya/gonp v1.0.4
 	github.com/davecgh/go-spew v1.1.1
+	github.com/gertd/go-pluralize v0.2.1
 	github.com/go-sql-driver/mysql v1.7.1
 	github.com/google/cel-go v0.17.1
 	github.com/google/go-cmp v0.5.9

go.mod

@@ -20,6 +20,8 @@ github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548/go.mod h1:e6NPNENfs
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gertd/go-pluralize v0.2.1 h1:M3uASbVjMnTsPb0PNqg+E/24Vwigyo/tvyMTtAlLgiA=
+github.com/gertd/go-pluralize v0.2.1/go.mod h1:rbYaKDbsXxmRfr8uygAEKhOWsjyrrqrkHVpZvoOp8zk=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
 github.com/go-logfmt/logfmt v0.5.0/go.mod h1:wCYkCAKZfumFQihp8CzCvQ3paCTfi41vtzG1KdI/P7A=
 github.com/go-sql-driver/mysql v1.7.1 h1:lUIinVbN1DY0xBg0eMOzmmtGoHwWBbvnWubQUrtU8EI=

go.sum

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"text/template"
 
+	"github.com/gertd/go-pluralize"
 	"github.com/kyleconroy/sqlc/internal/codegen/sdk"
 	"github.com/kyleconroy/sqlc/internal/metadata"
 	"github.com/kyleconroy/sqlc/internal/plugin"
@@ -159,6 +160,8 @@ func generate(req *plugin.CodeGenRequest, enums []Enum, structs []Struct, querie
 		"escape":     sdk.EscapeBacktick,
 		"imports":    i.Imports,
 		"hasPrefix":  strings.HasPrefix,
+		"toLower":    strings.ToLower,
+		"pluralize":  pluralize.NewClient().Plural,
 
 		// These methods are Go specific, they do not belong in the codegen package
 		// (as that is language independent)

internal/codegen/golang/gen.go

@@ -87,6 +87,31 @@ func (e *{{.Name}}) Scan(src interface{}) error {
 	return nil
 }
 
+{{if $.SQLDriver.IsPGX }}
+type {{ pluralize .Name }} []string
+
+{{if (eq $.SQLDriver.Package "pgx/v4") }}
+func (e *{{ pluralize .Name }}) DecodeText(ci *pgtype.ConnInfo, src []byte) error {
+	var dec pgtype.TextArray
+	if err := dec.DecodeText(ci, src); err != nil {
+		return err
+	}
+	for _, el := range dec.Elements {
+		*e = append(*e, el.String)
+	}
+	return nil
+}
+
+func (e {{ pluralize .Name }}) EncodeText(ci *pgtype.ConnInfo, buf []byte) ([]byte, error) {
+	var enc pgtype.TextArray
+	if err := enc.Set(e); err != nil {
+		return nil, err
+	}
+	return enc.EncodeText(ci, buf)
+}
+{{end}}
+{{end}}
+
 type Null{{.Name}} struct {
 	{{.Name}} {{.Name}} {{if .NameTag}}{{$.Q}}{{.NameTag}}{{$.Q}}{{end}}
   Valid  bool {{if .ValidTag}}{{$.Q}}{{.ValidTag}}{{$.Q}}{{end}} // Valid is true if {{.Name}} is not NULL
@@ -129,6 +154,12 @@ func All{{ .Name }}Values() []{{ .Name }} {
 {{ end }}
 {{end}}
 
+{{if and (gt (len .Enums) 0) (eq $.SQLDriver.Package "pgx/v5") }}
+var EnumNames = []string{
+	{{range .Enums}}{{toLower .Name | printf "%q"}},{{end}}
+}
+{{end}}
+
 {{range .Structs}}
 {{if .Comment}}{{comment .Comment}}{{end}}
 type {{.Name}} struct { {{- range .Fields}}