fix(generator): escape discriminator JSON names instead of allowlist filtering (#340)

* fix(generator): escape discriminator JSON names instead of allowlist filtering

The allowlist approach would silently break JSON deserialization for specs
with non-alphanumeric discriminator property names. Escape only the two
characters that break Go struct tag syntax (" and \) so the tag matches
the actual JSON key. Also align unmarshal.go.tmpl to use | quote pipe
consistently with oneof.go.tmpl.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix(generator): remove pre-escaping, rely on template quote pipe

The builder was escaping " and \ before the template applied
strconv.Quote via | quote, causing double-escaping. Remove
pre-escaping entirely — the | quote pipe in both templates
handles all necessary escaping for Go struct tag string literals.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: erraggy

generator/template_builders.go

@@ -444,15 +444,7 @@ func (cg *oas3CodeGenerator) buildOneOfTypeDefinition(typeName, originalName str
 	if schema.Discriminator != nil && schema.Discriminator.PropertyName != "" {
 		oneOfData.Discriminator = schema.Discriminator.PropertyName
 		oneOfData.DiscriminatorField = toFieldName(schema.Discriminator.PropertyName)
-		// Sanitize the discriminator property name to prevent injection in generated code.
-		// Only allow alphanumeric, underscore, hyphen, and dot — safe for JSON struct tags.
-		jsonName := strings.Map(func(r rune) rune {
-			if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' || r == '-' || r == '.' {
-				return r
-			}
-			return -1 // drop unsafe characters
-		}, schema.Discriminator.PropertyName)
-		oneOfData.DiscriminatorJSONName = jsonName
+		oneOfData.DiscriminatorJSONName = schema.Discriminator.PropertyName
 		oneOfData.HasUnmarshal = true
 
 		// Build unmarshal cases from discriminator mapping

generator/templates/types/unmarshal.go.tmpl

@@ -1,7 +1,7 @@
 // UnmarshalJSON implements json.Unmarshaler for {{.TypeName}}.
 func (u *{{.TypeName}}) UnmarshalJSON(data []byte) error {
 	var disc struct {
-		{{.DiscriminatorField}} string `json:"{{.DiscriminatorJSONName}}"`
+		{{.DiscriminatorField}} string `json:{{.DiscriminatorJSONName | quote}}`
 	}
 	if err := json.Unmarshal(data, &disc); err != nil {
 		return err