properly handle nullable and other db_type match parameters

Author: andrewmbenton

internal/codegen/golang/go_type.go

@@ -14,11 +14,7 @@ func addExtraGoStructTags(tags map[string]string, req *plugin.GenerateRequest, o
 		if oride.GoType.StructTags == nil {
 			continue
 		}
-		if oride.DbType != "" {
-			columnType := sdk.DataType(col.Type)
-			if columnType != oride.DbType {
-				continue
-			}
+		if override.MatchesColumn(col) {
 			for k, v := range oride.GoType.StructTags {
 				tags[k] = v
 			}
@@ -74,16 +70,13 @@ func goType(req *plugin.GenerateRequest, options *opts.Options, col *plugin.Colu
 }
 
 func goInnerType(req *plugin.GenerateRequest, options *opts.Options, col *plugin.Column) string {
-	columnType := sdk.DataType(col.Type)
-	notNull := col.NotNull || col.IsArray
-
 	// package overrides have a higher precedence
 	for _, override := range options.Overrides {
 		oride := override.ShimOverride
 		if oride.GoType.TypeName == "" {
 			continue
 		}
-		if oride.DbType != "" && oride.DbType == columnType && oride.Nullable != notNull && oride.Unsigned == col.Unsigned {
+		if override.MatchesColumn(col) {
 			return oride.GoType.TypeName
 		}
 	}

internal/codegen/golang/opts/override.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/sqlc-dev/sqlc/internal/codegen/sdk"
 	"github.com/sqlc-dev/sqlc/internal/pattern"
 	"github.com/sqlc-dev/sqlc/internal/plugin"
 )
@@ -76,6 +77,12 @@ func (o *Override) Matches(n *plugin.Identifier, defaultSchema string) bool {
 	return true
 }
 
+func (o *Override) MatchesColumn(col *plugin.Column) bool {
+	columnType := sdk.DataType(col.Type)
+	notNull := col.NotNull || col.IsArray
+	return o.DBType != "" && o.DBType == columnType && o.Nullable != notNull && o.Unsigned == col.Unsigned
+}
+
 func (o *Override) parse(req *plugin.GenerateRequest) (err error) {
 	// validate deprecated postgres_type field
 	if o.Deprecated_PostgresType != "" {