BugFix: Optional GraphQL fields no longer had the serde(skip_serializing_if = "Option::is_none") option. Also added a unit test for that

JeremieRodon · JeremieRodon · commit dff2081b9395 · 2025-09-11T15:18:39.000+02:00
diff --git a/lambda-appsync-proc/src/appsync_lambda_main/graphql.rs b/lambda-appsync-proc/src/appsync_lambda_main/graphql.rs
@@ -195,7 +195,7 @@ impl ToTokens for FieldContext<'_> {
         }
         if field_type.is_optionnal() {
             serde_options.push(quote_spanned! {span=>
-                default
+                default, skip_serializing_if = "Option::is_none"
             });
         }
         if !serde_options.is_empty() {
diff --git a/lambda-appsync/tests/serde_test.rs b/lambda-appsync/tests/serde_test.rs
@@ -187,4 +187,8 @@ fn test_null_handling() {
 
     let optional_team: OptionalTeam = serde_json::from_value(json.clone()).unwrap();
     assert_eq!(optional_team.team, Some(Team::Rust));
+
+    // Test that null team is not serialized
+    let optional_team = OptionalTeam { team: None };
+    assert_eq!(serde_json::to_value(optional_team).unwrap(), json!({}));
 }

Original file line number	Diff line number	Diff line change
`@@ -195,7 +195,7 @@ impl ToTokens for FieldContext<'_> {`
`195`	`195`	`}`
`196`	`196`	`if field_type.is_optionnal() {`
`197`	`197`	`serde_options.push(quote_spanned! {span=>`
`198`		`- default`
	`198`	`+ default, skip_serializing_if = "Option::is_none"`
`199`	`199`	`});`
`200`	`200`	`}`
`201`	`201`	`if !serde_options.is_empty() {`
Original file line number	Diff line number	Diff line change
`@@ -187,4 +187,8 @@ fn test_null_handling() {`
`187`	`187`
`188`	`188`	`let optional_team: OptionalTeam = serde_json::from_value(json.clone()).unwrap();`
`189`	`189`	`assert_eq!(optional_team.team, Some(Team::Rust));`
	`190`	`+`
	`191`	`+ // Test that null team is not serialized`
	`192`	`+ let optional_team = OptionalTeam { team: None };`
	`193`	`+ assert_eq!(serde_json::to_value(optional_team).unwrap(), json!({}));`
`190`	`194`	`}`