Correctly reset optional fields in struct

java/src/main/java/com/example/otelstef/ExpHistogramValue.java

@@ -90,6 +90,7 @@ void reset() {
             negativeBuckets.reset();
         }
         zeroThreshold = 0.0;
+        optionalFieldsPresent = 0;
     }
 
 

java/src/main/java/com/example/otelstef/HistogramValue.java

@@ -72,6 +72,7 @@ void reset() {
         if (bucketCounts != null) {
             bucketCounts.reset();
         }
+        optionalFieldsPresent = 0;
     }
 
 

stefc/generator/testdata/optional_reset_fail.stef

@@ -0,0 +1,14 @@
+// This schema was failing (for seed 1765233907441407000) because
+// optional struct fields were not reset correctly by reset() method.
+package com.example.gentest.optional_reset_fail
+
+multimap MultiMap1 {
+  key Struct1
+  value int64
+}
+
+struct Struct1 root {
+  Field1 bytes optional
+  Field2 MultiMap1
+  Field3 Struct1 optional
+}

stefc/generator/testdata/seeds/optional_reset_fail_Struct1_seeds.txt

@@ -0,0 +1 @@
+1765234703981295000

stefc/templates/go/struct.go.tmpl

@@ -138,6 +138,9 @@ func (s *{{ $.StructName }}) reset() {
     {{- end -}}
     {{- end -}}
     {{- end -}}
+    {{- if .OptionalFieldCount}}
+    s.optionalFieldsPresent = 0
+    {{- end}}
 }
 
 // fixParent sets the parentModifiedFields pointer to the supplied value.

stefc/templates/java/struct.java.tmpl

@@ -79,6 +79,9 @@ public class {{ .StructName }} {
 
         {{- end }}
         {{- end }}
+        {{- if .OptionalFieldCount}}
+        optionalFieldsPresent = 0;
+        {{- end}}
     }
 
     {{ range .Fields }}