Make sure user input UUIDs through REST API are unique

API/Backend/Config/routes/configs.js

@@ -693,6 +693,14 @@ function addLayer(req, res, next, cb, forceConfig, caller = "addLayer") {
             );
           }
 
+          // This adds the proposed_uuid key to all of the new layers/sublayers to be added that have
+          // user defined UUIDs. We remove the proposed_uuid key after using it to check for unique UUIDs.
+          Utils.traverseLayers([req.body.layer], (layer) => {
+            if (layer.uuid != null) {
+                layer.proposed_uuid = layer.uuid;
+            }
+          });
+
           const didSet = Utils.setIn(
             config.layers,
             `${placementPath}${placementIndex}`,

API/Backend/Config/uuids.js

@@ -4,6 +4,14 @@ const { v4: uuidv4, validate: uuidValidate } = require("uuid");
 
 const populateUUIDs = (config) => {
   const newlyAddedUUIDs = [];
+  const definedUUIDs = [];
+
+  // Track of all of the previously defined UUIDs (i.e. ignore the UUIDs of the newly added layers)
+  Utils.traverseLayers(config.layers, (layer) => {
+    if (layer.uuid != null && !layer.proposed_uuid) {
+      definedUUIDs.push(layer.uuid)
+    }
+  });
 
   Utils.traverseLayers(config.layers, (layer) => {
     if (layer.uuid == null) {
@@ -12,16 +20,23 @@ const populateUUIDs = (config) => {
         name: layer.name,
         uuid: layer.uuid,
       });
-    } else if (!uuidValidate(layer.uuid)) {
+    } else if (!uuidValidate(layer.uuid) || definedUUIDs.includes(layer.proposed_uuid)) {
       const badUUID = layer.uuid;
       layer.uuid = uuidv4();
       newlyAddedUUIDs.push({
         name: layer.name,
         uuid: layer.uuid,
         replacesBadUUID: badUUID,
       });
+    } else {
+      definedUUIDs.push(layer.uuid);
+    }
+
+    if (layer.proposed_uuid) {
+      delete layer.proposed_uuid;
     }
   });
+
   return newlyAddedUUIDs;
 };