From 4be7109a2b92c0029779281f3f3a7ffd184df3ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Bombeck?= <mbombeck@gmail.com>
Date: Sun, 4 Oct 2026 21:13:28 +0200
Subject: [PATCH] fix(medications): refetch an invalidated prefetch on mount

A hover prefetch excused the mount refetch even after a dose logged
elsewhere had invalidated the medication reads, so the page showed the
compliance from before the dose. An invalidated entry now always
refetches.
---
 .../__tests__/prefetch-medications.test.ts    | 22 +++++++++++++++++++
 src/lib/queries/prefetch-medications.ts       |  9 +++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/lib/queries/__tests__/prefetch-medications.test.ts b/src/lib/queries/__tests__/prefetch-medications.test.ts
index 22ee0f750..dc004b368 100644
--- a/src/lib/queries/__tests__/prefetch-medications.test.ts
+++ b/src/lib/queries/__tests__/prefetch-medications.test.ts
@@ -125,6 +125,28 @@ describe("refetchMedicationsOnMount", () => {
     unsubscribe();
   });
 
+  it("refetches a prefetched read that was invalidated before the mount", async () => {
+    // Hover the nav link, then log a dose elsewhere before the page mounts:
+    // the dose invalidates the medication reads, and the prefetched answer
+    // no longer holds the compliance the user just changed.
+    const { client, calls } = setup();
+    prefetchMedicationsList(client);
+    await vi.waitFor(() => expect(calls("/api/medications")).toBe(1));
+    await vi.waitFor(() =>
+      expect(client.getQueryState(queryKeys.medications())?.status).toBe(
+        "success",
+      ),
+    );
+    await client.invalidateQueries({ queryKey: queryKeys.medications() });
+    expect(client.getQueryState(queryKeys.medications())?.isInvalidated).toBe(
+      true,
+    );
+
+    const { refetched, unsubscribe } = await mountList(client);
+    expect(refetched).toBe(true);
+    unsubscribe();
+  });
+
   it("still refetches on mount when the cache holds an older read", async () => {
     const { client } = setup();
     const queryFn = vi.fn(async () => []);
diff --git a/src/lib/queries/prefetch-medications.ts b/src/lib/queries/prefetch-medications.ts
index 6058fc137..d78e63c52 100644
--- a/src/lib/queries/prefetch-medications.ts
+++ b/src/lib/queries/prefetch-medications.ts
@@ -93,11 +93,18 @@ export function prefetchMedicationsList(
  * the identical request a second time, a few hundred milliseconds after the
  * first answer landed, on every visit to the page. A return to the page with
  * an older cache entry, or a direct load, still refetches on mount.
+ *
+ * An invalidated entry always refetches: a dose logged elsewhere in the app
+ * between the prefetch and the mount invalidates these reads, and the
+ * prefetched answer is then the stale one.
  */
 export function refetchMedicationsOnMount(
   read: MedicationsRead,
-): (query: { state: { dataUpdatedAt: number } }) => boolean | "always" {
+): (query: {
+  state: { dataUpdatedAt: number; isInvalidated: boolean };
+}) => boolean | "always" {
   return (query) => {
+    if (query.state.isInvalidated) return "always";
     const startedAt = prefetchStartedAt.get(read);
     const answeredThisVisit =
       startedAt !== undefined &&