handle better empty tag overrides

backend/windmill-common/src/flows.rs

@@ -424,7 +424,7 @@ pub enum FlowModuleValue {
         path: String,
         #[serde(skip_serializing_if = "Option::is_none")]
         hash: Option<ScriptHash>,
-        #[serde(deserialize_with = "empty_string_as_none")]
+        #[serde(skip_serializing_if = "Option::is_none")]
         tag_override: Option<String>,
     },
     Flow {
@@ -482,14 +482,6 @@ fn is_none_or_empty(expr: &Option<String>) -> bool {
     expr.is_none() || expr.as_ref().unwrap().is_empty()
 }
 
-fn empty_string_as_none<'de, D>(deserializer: D) -> Result<Option<String>, D::Error>
-where
-    D: serde::Deserializer<'de>,
-{
-    let s: Option<String> = Option::deserialize(deserializer)?;
-    Ok(s.filter(|s| !s.is_empty()))
-}
-
 #[derive(Deserialize)]
 struct UntaggedFlowModuleValue {
     #[serde(rename = "type")]
@@ -498,7 +490,6 @@ struct UntaggedFlowModuleValue {
     input_transforms: Option<HashMap<String, InputTransform>>,
     path: Option<String>,
     hash: Option<ScriptHash>,
-    #[serde(deserialize_with = "empty_string_as_none")]
     tag_override: Option<String>,
     iterator: Option<InputTransform>,
     modules: Option<Vec<FlowModule>>,

backend/windmill-worker/src/worker_flow.rs

@@ -3761,6 +3761,11 @@ async fn script_to_payload(
     module: &FlowModule,
     tag_override: &Option<String>,
 ) -> Result<JobPayloadWithTag, Error> {
+    let tag_override = if tag_override.as_ref().is_some_and(|x| x.trim().is_empty()) {
+        None
+    } else {
+        tag_override.clone()
+    };
     let (payload, tag, delete_after_use, script_timeout) = if script_hash.is_none() {
         let (jp, tag, delete_after_use, script_timeout) =
             script_path_to_payload(script_path, db, &flow_job.workspace_id, Some(true)).await?;

frontend/src/lib/components/ModulePreview.svelte

@@ -75,7 +75,7 @@
 				script.content,
 				script.language,
 				args,
-				$flowStore?.tag ?? val.tag_override ?? script.tag
+				$flowStore?.tag ?? (val.tag_override ? val.tag_override : script.tag)
 			)
 		} else if (val.type == 'flow') {
 			await testJobLoader?.abstractRun(() =>