Port dynamic node improvements from ComfyUI-JSON-Dynamic

- Deferred output cleanup (_configured flag + queueMicrotask) to prevent
  breaking links when other nodes (e.g. Kijai Set/Get) resolve outputs
  during graph loading
- file_not_found error handling in refresh to keep existing outputs intact
- Fallback widget sync in onConfigure when widget values are empty but
  serialized outputs exist

Applied to both json_dynamic.js and project_dynamic.js.

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

json_loader.py

@@ -75,6 +75,8 @@ if PromptServer is not None:
         except (ValueError, TypeError):
             seq = 1
         data = read_json_data(json_path)
+        if not data:
+            return web.json_response({"keys": [], "types": [], "error": "file_not_found"})
         target = get_batch_item(data, seq)
         keys = []
         types = []

web/json_dynamic.js

@@ -17,17 +17,31 @@ app.registerExtension({
                 if (w) { w.type = "hidden"; w.computeSize = () => [0, -4]; }
             }
 
-            // Remove all 32 default outputs from Python RETURN_TYPES
+            // Do NOT remove default outputs synchronously here.
-            while (this.outputs.length > 0) {
+            // During graph loading, ComfyUI creates all nodes (firing onNodeCreated)
-                this.removeOutput(0);
+            // before configuring them. Other nodes (e.g. Kijai Set/Get) may resolve
-            }
+            // links to our outputs during their configure step. If we remove outputs
+            // here, those nodes find no output slot and error out.
+            //
+            // Instead, defer cleanup: for loaded workflows onConfigure sets _configured
+            // before this runs; for new nodes the defaults are cleaned up.
+            this._configured = false;
 
             // Add Refresh button
             this.addWidget("button", "Refresh Outputs", null, () => {
                 this.refreshDynamicOutputs();
             });
 
-            this.setSize(this.computeSize());
+            queueMicrotask(() => {
+                if (!this._configured) {
+                    // New node (not loading) — remove the 32 Python default outputs
+                    while (this.outputs.length > 0) {
+                        this.removeOutput(0);
+                    }
+                    this.setSize(this.computeSize());
+                    app.graph?.setDirtyCanvas(true, true);
+                }
+            });
         };
 
         nodeType.prototype.refreshDynamicOutputs = async function () {
@@ -39,7 +53,14 @@ app.registerExtension({
                 const resp = await api.fetchApi(
                     `/json_manager/get_keys?path=${encodeURIComponent(pathWidget.value)}&sequence_number=${seqWidget?.value || 1}`
                 );
-                const { keys, types } = await resp.json();
+                const data = await resp.json();
+                const { keys, types } = data;
+
+                // If the file wasn't found, keep existing outputs and links intact
+                if (data.error === "file_not_found") {
+                    console.warn("[JSONLoaderDynamic] File not found, keeping existing outputs:", pathWidget.value);
+                    return;
+                }
 
                 // Store keys and types in hidden widgets for persistence
                 const okWidget = this.widgets?.find(w => w.name === "output_keys");
@@ -82,7 +103,6 @@ app.registerExtension({
 
                 // Reassign the outputs array and fix link slot indices
                 this.outputs = newOutputs;
-                // Update link origin_slot to match new positions
                 if (this.graph) {
                     for (let i = 0; i < this.outputs.length; i++) {
                         const links = this.outputs[i].links;
@@ -105,6 +125,7 @@ app.registerExtension({
         const origOnConfigure = nodeType.prototype.onConfigure;
         nodeType.prototype.onConfigure = function (info) {
             origOnConfigure?.apply(this, arguments);
+            this._configured = true;
 
             // Hide internal widgets
             for (const name of ["output_keys", "output_types"]) {
@@ -122,16 +143,23 @@ app.registerExtension({
                 ? otWidget.value.split(",")
                 : [];
 
-            // On load, LiteGraph already restored serialized outputs with links.
+            if (keys.length > 0) {
-            // Rename and set types to match stored state (preserves links).
+                // On load, LiteGraph already restored serialized outputs with links.
-            for (let i = 0; i < this.outputs.length && i < keys.length; i++) {
+                // Rename and set types to match stored state (preserves links).
-                this.outputs[i].name = keys[i].trim();
+                for (let i = 0; i < this.outputs.length && i < keys.length; i++) {
-                if (types[i]) this.outputs[i].type = types[i];
+                    this.outputs[i].name = keys[i].trim();
-            }
+                    if (types[i]) this.outputs[i].type = types[i];
+                }
 
-            // Remove any extra outputs beyond the key count
+                // Remove any extra outputs beyond the key count
-            while (this.outputs.length > keys.length) {
+                while (this.outputs.length > keys.length) {
-                this.removeOutput(this.outputs.length - 1);
+                    this.removeOutput(this.outputs.length - 1);
+                }
+            } else if (this.outputs.length > 0) {
+                // Widget values empty but serialized outputs exist — sync widgets
+                // from the outputs LiteGraph already restored (fallback).
+                if (okWidget) okWidget.value = this.outputs.map(o => o.name).join(",");
+                if (otWidget) otWidget.value = this.outputs.map(o => o.type).join(",");
             }
 
             this.setSize(this.computeSize());

web/project_dynamic.js

@@ -17,17 +17,31 @@ app.registerExtension({
                 if (w) { w.type = "hidden"; w.computeSize = () => [0, -4]; }
             }
 
-            // Remove all 32 default outputs from Python RETURN_TYPES
+            // Do NOT remove default outputs synchronously here.
-            while (this.outputs.length > 0) {
+            // During graph loading, ComfyUI creates all nodes (firing onNodeCreated)
-                this.removeOutput(0);
+            // before configuring them. Other nodes (e.g. Kijai Set/Get) may resolve
-            }
+            // links to our outputs during their configure step. If we remove outputs
+            // here, those nodes find no output slot and error out.
+            //
+            // Instead, defer cleanup: for loaded workflows onConfigure sets _configured
+            // before this runs; for new nodes the defaults are cleaned up.
+            this._configured = false;
 
             // Add Refresh button
             this.addWidget("button", "Refresh Outputs", null, () => {
                 this.refreshDynamicOutputs();
             });
 
-            this.setSize(this.computeSize());
+            queueMicrotask(() => {
+                if (!this._configured) {
+                    // New node (not loading) — remove the 32 Python default outputs
+                    while (this.outputs.length > 0) {
+                        this.removeOutput(0);
+                    }
+                    this.setSize(this.computeSize());
+                    app.graph?.setDirtyCanvas(true, true);
+                }
+            });
         };
 
         nodeType.prototype.refreshDynamicOutputs = async function () {
@@ -42,7 +56,14 @@ app.registerExtension({
                 const resp = await api.fetchApi(
                     `/json_manager/get_project_keys?url=${encodeURIComponent(urlWidget.value)}&project=${encodeURIComponent(projectWidget.value)}&file=${encodeURIComponent(fileWidget.value)}&seq=${seqWidget?.value || 1}`
                 );
-                const { keys, types } = await resp.json();
+                const data = await resp.json();
+                const { keys, types } = data;
+
+                // If the API returned an error, keep existing outputs and links intact
+                if (data.error) {
+                    console.warn("[ProjectLoaderDynamic] API error, keeping existing outputs:", data.error);
+                    return;
+                }
 
                 // Store keys and types in hidden widgets for persistence
                 const okWidget = this.widgets?.find(w => w.name === "output_keys");
@@ -105,6 +126,7 @@ app.registerExtension({
         const origOnConfigure = nodeType.prototype.onConfigure;
         nodeType.prototype.onConfigure = function (info) {
             origOnConfigure?.apply(this, arguments);
+            this._configured = true;
 
             // Hide internal widgets
             for (const name of ["output_keys", "output_types"]) {
@@ -122,15 +144,23 @@ app.registerExtension({
                 ? otWidget.value.split(",")
                 : [];
 
-            // Rename and set types to match stored state (preserves links)
+            if (keys.length > 0) {
-            for (let i = 0; i < this.outputs.length && i < keys.length; i++) {
+                // On load, LiteGraph already restored serialized outputs with links.
-                this.outputs[i].name = keys[i].trim();
+                // Rename and set types to match stored state (preserves links).
-                if (types[i]) this.outputs[i].type = types[i];
+                for (let i = 0; i < this.outputs.length && i < keys.length; i++) {
-            }
+                    this.outputs[i].name = keys[i].trim();
+                    if (types[i]) this.outputs[i].type = types[i];
+                }
 
-            // Remove any extra outputs beyond the key count
+                // Remove any extra outputs beyond the key count
-            while (this.outputs.length > keys.length) {
+                while (this.outputs.length > keys.length) {
-                this.removeOutput(this.outputs.length - 1);
+                    this.removeOutput(this.outputs.length - 1);
+                }
+            } else if (this.outputs.length > 0) {
+                // Widget values empty but serialized outputs exist — sync widgets
+                // from the outputs LiteGraph already restored (fallback).
+                if (okWidget) okWidget.value = this.outputs.map(o => o.name).join(",");
+                if (otWidget) otWidget.value = this.outputs.map(o => o.type).join(",");
             }
 
             this.setSize(this.computeSize());