fix(web): sort equally merge-ready pull requests by diff size

apps/web/src/components/pullRequest/pullRequestList.logic.test.ts

@@ -723,6 +723,7 @@ describe("default merge-readiness ranking", () => {
       number: 4,
       checksState: "passing",
       reviewDecision: "approved",
+      additions: 1_000,
       updatedAt: "2026-06-01T00:00:00Z",
     });
     const draft = entry({
@@ -747,7 +748,7 @@ describe("default merge-readiness ranking", () => {
     ).toEqual([4, 3, 5, 2, 6, 1]);
   });
 
-  it("uses recency inside one readiness tier", () => {
+  it("uses recency when readiness and diff size tie", () => {
     const older = entry({ number: 1, checksState: "passing" });
     const newer = entry({
       number: 2,
@@ -760,13 +761,13 @@ describe("default merge-readiness ranking", () => {
     ]);
   });
 
-  it("keeps readiness order stable when optional diff counts arrive", () => {
+  it("ranks smaller measured diffs first within a readiness tier as counts arrive", () => {
     const larger = entry({
       number: 1,
       checksState: "passing",
       reviewDecision: "approved",
-      additions: 40,
-      deletions: 10,
+      additions: 1,
+      deletions: 49,
       updatedAt: "2026-09-01T00:00:00Z",
     });
     const smaller = entry({
@@ -788,14 +789,30 @@ describe("default merge-readiness ranking", () => {
 
     expect(
       rankPullRequestsByMergeReadiness([larger, unknown, smaller]).map((row) => row.number),
-    ).toEqual([3, 1, 2]);
+    ).toEqual([2, 1, 3]);
     expect(
       rankPullRequestsByMergeReadiness([
         larger,
-        { ...unknown, additions: 500, deletions: 200 },
+        { ...unknown, additions: 1, deletions: 0 },
         smaller,
       ]).map((row) => row.number),
-    ).toEqual([3, 1, 2]);
+    ).toEqual([3, 2, 1]);
+  });
+
+  it("distinguishes measured empty diffs from missing counts when sorting groups", () => {
+    const unknown = entry({ number: 1, additions: 0, deletions: 0 });
+    const measured = entry({ number: 2 });
+    const empty = entry({ number: 3, additions: 0, deletions: 0 });
+    const groups = [
+      { key: "others", label: "Others", entries: [unknown, measured, empty] },
+    ] as const;
+
+    const sorted = sortPullRequestGroups(groups, "ready", "", (row) => row.number !== 1);
+
+    expect(sorted[0]!.entries.map((row) => row.number)).toEqual([3, 2, 1]);
+    expect(sortPullRequestGroups(groups, "ready", "sidebar", (row) => row.number !== 1)).toEqual(
+      groups,
+    );
   });
 
   it("keeps authored work first and ranks each group by readiness", () => {

apps/web/src/components/pullRequest/pullRequestList.logic.ts

@@ -1010,10 +1010,12 @@ export function rankPullRequestMatches<Entry extends PullRequestListEntry>(
  * verdict, then everything else still open. Drafts stay in that third tier because their author
  * has not made them mergeable yet. Finished work follows open work when all states are visible. A
  * known conflict is never ready, whatever its checks, review or state say, so it stays at the
- * bottom. Recency breaks ties, so optional diff counts never move the queue beneath the reader.
+ * bottom. Within each tier, smaller measured diffs come first, then unknown sizes. Recency
+ * breaks ties between equally sized diffs.
  */
 export function rankPullRequestsByMergeReadiness<Entry extends PullRequestListEntry>(
   entries: ReadonlyArray<Entry>,
+  hasMeasuredSize: (entry: Entry) => boolean = (entry) => entry.additions + entry.deletions > 0,
 ): ReadonlyArray<Entry> {
   const tier = (entry: Entry) => {
     if (entry.mergeability === "conflicting") return 4;
@@ -1026,7 +1028,9 @@ export function rankPullRequestsByMergeReadiness<Entry extends PullRequestListEn
   return entries.toSorted((left, right) => {
     const byTier = tier(left) - tier(right);
     if (byTier !== 0) return byTier;
-    return right.updatedAt.localeCompare(left.updatedAt);
+    const measured = Number(hasMeasuredSize(right)) - Number(hasMeasuredSize(left));
+    const sized = left.additions + left.deletions - (right.additions + right.deletions);
+    return measured || sized || right.updatedAt.localeCompare(left.updatedAt);
   });
 }
 
@@ -1042,7 +1046,7 @@ export function sortPullRequestGroups<Entry extends PullRequestListEntry>(
 
   if (sort === "ready") {
     return searchText.trim().length === 0
-      ? sortWithinGroups(rankPullRequestsByMergeReadiness)
+      ? sortWithinGroups((entries) => rankPullRequestsByMergeReadiness(entries, hasMeasuredSize))
       : groups;
   }
   if (sort === "updated") return groups;

apps/web/src/routes/_chat.pull-requests.tsx

@@ -292,7 +292,7 @@ function PullRequestsRouteView() {
   const search = Route.useSearch();
   const sort = search.sort ?? "ready";
   const statsPolicy: PullRequestStatsPolicy =
-    sort === "largest" || sort === "smallest" ? "eager" : "visible";
+    sort === "ready" || sort === "largest" || sort === "smallest" ? "eager" : "visible";
   const navigate = useNavigate({ from: Route.fullPath });
   const keybindings = useAtomValue(primaryServerKeybindingsAtom);
   const { environments } = useEnvironments();
@@ -826,7 +826,7 @@ function PullRequestsRouteView() {
   // from the first moment rather than the second: a button that stays live through the slow half
   // of its own work is a button that gets pressed again, and buys the whole cascade twice.
   const [invalidating, setInvalidating] = useState(false);
-  const refreshFromHost = async () => {
+  const refreshFromHost = async (includeDetail = true) => {
     const requestedStatsScope = statsScopeRef.current;
     setInvalidating(true);
     try {
@@ -851,7 +851,7 @@ function PullRequestsRouteView() {
       setStatsTargetState({ key: requestedStatsScope.key, batches });
       statsQuery.refresh(batches.map(({ environmentId, input }) => ({ environmentId, input })));
     }
-    setDetailRefreshToken((token) => token + 1);
+    if (includeDetail) setDetailRefreshToken((token) => token + 1);
   };
   const refreshing = invalidating || listQuery.isPending;
 
@@ -1270,8 +1270,8 @@ function PullRequestsRouteView() {
     viewers,
   ]);
 
-  // Date sorts keep optional line-count reads near the viewport. Size sorts need every loaded
-  // count before their order is final. Received counts stay cached across both policies.
+  // Date sorts keep optional line-count reads near the viewport. Size and readiness sorts need
+  // every loaded count before their order is final. Counts stay cached across both policies.
   const entriesByStatsKey = useRef<ReadonlyMap<string, EnvironmentPullRequestEntry>>(new Map());
   entriesByStatsKey.current = new Map(
     groups.flatMap((group) =>
@@ -1950,10 +1950,10 @@ function PullRequestsRouteView() {
                 ) ?? null
               }
               refreshToken={detailRefreshToken}
-              // Merging, closing or reopening changes the row this panel was opened from, so
-              // the list behind it is out of date the moment the host takes the action.
+              // Host actions can change both readiness and diff size, so refresh the counts
+              // alongside the list. The panel already refreshes itself after each action.
               onActed={() => {
-                refreshList(true);
+                void refreshFromHost(false);
               }}
             />
           </RightPanelTabs>