fix nullable additional properties

Author: PatrickKoss

languages/golang/compat-layer/templates/field_type.mustache

@@ -0,0 +1,8 @@
+{{!
+  Renders the Go type for a property, accounting for nullable additionalProperties.
+  Upstream Go codegen ignores `nullable: true` inside additionalProperties when
+  computing the map value type, producing `map[string]string` instead of
+  `map[string]*string`. This partial restores the missing `*` on the map value
+  when the additionalProperties schema is nullable, and otherwise emits
+  the upstream-computed dataType unchanged.
+}}{{#isMap}}{{#additionalProperties.isNullable}}map[string]*{{{additionalProperties.dataType}}}{{/additionalProperties.isNullable}}{{^additionalProperties.isNullable}}{{{dataType}}}{{/additionalProperties.isNullable}}{{/isMap}}{{^isMap}}{{{dataType}}}{{/isMap}}

languages/golang/compat-layer/templates/model_simple.mustache

@@ -633,11 +633,11 @@ func set{{classname}}{{getter}}AttributeType(arg *{{classname}}{{getter}}Attribu
 {{^isArray}}
 // isContainer
 // Deprecated: Will be removed after 2026-09-30. Move to the packages generated for each available API version instead
-type {{classname}}{{getter}}AttributeType = *{{dataType}}
+type {{classname}}{{getter}}AttributeType = *{{>field_type}}
 // Deprecated: Will be removed after 2026-09-30. Move to the packages generated for each available API version instead
-type {{classname}}{{getter}}ArgType = {{#isNullable}}*{{/isNullable}}{{dataType}}
+type {{classname}}{{getter}}ArgType = {{#isNullable}}*{{/isNullable}}{{>field_type}}
 // Deprecated: Will be removed after 2026-09-30. Move to the packages generated for each available API version instead
-type {{classname}}{{getter}}RetType = {{#isNullable}}*{{/isNullable}}{{dataType}}
+type {{classname}}{{getter}}RetType = {{#isNullable}}*{{/isNullable}}{{>field_type}}
 // Deprecated: Will be removed after 2026-09-30. Move to the packages generated for each available API version instead
 func get{{classname}}{{getter}}AttributeTypeOk(arg {{classname}}{{getter}}AttributeType) (ret {{classname}}{{getter}}RetType, ok bool) {
 	if arg == nil {

languages/golang/templates/field_type.mustache

@@ -0,0 +1,8 @@
+{{!
+  Renders the Go type for a property, accounting for nullable additionalProperties.
+  Upstream Go codegen ignores `nullable: true` inside additionalProperties when
+  computing the map value type, producing `map[string]string` instead of
+  `map[string]*string`. This partial restores the missing `*` on the map value
+  when the additionalProperties schema is nullable, and otherwise emits
+  the upstream-computed dataType unchanged.
+}}{{#isMap}}{{#additionalProperties.isNullable}}map[string]*{{{additionalProperties.dataType}}}{{/additionalProperties.isNullable}}{{^additionalProperties.isNullable}}{{{dataType}}}{{/additionalProperties.isNullable}}{{/isMap}}{{^isMap}}{{{dataType}}}{{/isMap}}