Fix coalescing breaking isLoading/activeQueryId invariant (v1.0.15)

CRITICAL BUG: The impossible state (isLoading=true + activeQueryId=null) was caused
by coalescing paths setting isLoading without setting activeQueryId.

The Bug You Found:
User reported seeing isLoading=true but activeQueryId=null, which should be
impossible. This breaks the core invariant that activeQueryId should be set
whenever isLoading=true.

Root Cause:
When a request coalesced to an existing in-flight request:
- Line 1519: Collection coalescing set isLoading=true, no activeQueryId
- Line 1576: Item coalescing set isLoading=true, no activeQueryId

Timeline:
1. First request: activeQueryId=qid1, isLoading=true
2. Second request coalesces: isLoading=true (again), activeQueryId still qid1
3. First request completes: activeQueryId=null, isLoading=false
4. Second request sees: activeQueryId=null, isLoading=true ← IMPOSSIBLE STATE

The Fix:
1. Removed isLoading=true assignments from coalescing paths
2. Added isCollectionLoading() function (parallel to isItemLoading)
3. Updated fetchCollection to sync isLoading with in-flight state
4. Updated fetchItem already had this sync (line 1713-1716)
5. Exported isCollectionLoading in public API

Now both fetchItem and fetchCollection sync isLoading with actual in-flight
state, maintaining the invariant without breaking it in coalescing paths.

The Invariant:
  if (isLoading === true) then (activeQueryId !== null OR in-flight request exists)

Version: 1.0.14 → 1.0.15

Author: YidiDev

package.json

@@ -1,6 +1,6 @@
 {
   "name": "verity-dl",
-  "version": "1.0.14",
+  "version": "1.0.15",
   "description": "A framework agnostic data layer built to handle the communication layer between the server and the client seamlessly and keep the ui state always up to date with the source of truth",
   "main": "verity/shared/static/lib/core.js",
   "module": "verity/shared/static/lib/core.js",

verity/shared/static/lib/core.js

@@ -1241,6 +1241,11 @@ function isItemLoading(typeName, id, levelName = null) {
     return G.inFlightItm.has(key);
 }
 
+function isCollectionLoading(name, params) {
+    const key = collectionKey(name, params);
+    return G.inFlightCol.has(key);
+}
+
 function hasAnyInFlightRequests() {
     return G.inFlightItm.size > 0 || G.inFlightCol.size > 0;
 }
@@ -1516,7 +1521,8 @@ async function _startCollectionFetch(name, { force = false, params = undefined }
 
     if (G.inFlightCol.has(inFlightKey)) {
         const bucket = G.inFlightCol.get(inFlightKey);
-        if (!ref.meta.isLoading) assignRef(ref, { meta: { ...ref.meta, isLoading: true, error: null } });
+        // Don't update isLoading here - it will be synced with in-flight state if needed
+        // Setting isLoading=true without activeQueryId breaks the invariant
         emitLifecycle("collection:fetch:coalesced", { name, params: snapshot, key: inFlightKey });
         return bucket.promise;
     }
@@ -1572,8 +1578,8 @@ async function _startItemFetch(typeName, id, levelName, { loud = false, force =
     // If a request for this item/level is already in-flight, coalesce.
     if (G.inFlightItm.has(key)) {
         const bucket = G.inFlightItm.get(key);
-        // If a later caller is loud, reflect spinner even though we're reusing the same request
-        if (loud && !ref.meta.isLoading) assignRef(ref, { meta: { ...ref.meta, isLoading: true } });
+        // Don't update isLoading here - it will be synced at the end of fetchItem
+        // Setting isLoading=true without activeQueryId breaks the invariant (isLoading=true + activeQueryId=null)
         emitLifecycle("item:fetch:coalesced", { ...eventBase, loud: !!loud, key });
         return bucket.promise;
     }
@@ -1699,6 +1705,13 @@ function fetchCollection(name, opts = {}) {
     ref.meta.lastUsedAt = nowISO();
     scheduleMemorySweep();
     _startCollectionFetch(name, opts);
+    
+    // Set isLoading based on actual in-flight state (source of truth)
+    const actuallyLoading = isCollectionLoading(name, opts.params);
+    if (ref.meta.isLoading !== actuallyLoading) {
+        assignRef(ref, { meta: { ...ref.meta, isLoading: actuallyLoading } });
+    }
+    
     return ref;
 }
 
@@ -2139,6 +2152,7 @@ const DLCore = {
     disconnectSse,
     ingestDirectiveEnvelope,
     isItemLoading,
+    isCollectionLoading,
     hasAnyInFlightRequests,
 };
 
@@ -2164,6 +2178,7 @@ if (typeof exports !== "undefined") {
     exports.disconnectSse = disconnectSse;
     exports.ingestDirectiveEnvelope = ingestDirectiveEnvelope;
     exports.isItemLoading = isItemLoading;
+    exports.isCollectionLoading = isCollectionLoading;
     exports.hasAnyInFlightRequests = hasAnyInFlightRequests;
 }