List folders in sidebar order in the move-to picker

The picker sorted folders A-Z by path, with Inbox first, so a folder
dragged into place in the sidebar turned up somewhere else when moving
mail. It now walks the tree in compareFolders order, the sidebar's
order with every folder expanded: Inbox, then the saved order, then
the special folders, then A-Z, with subfolders under their parent.

treeOrder lives beside compareFolders. A folder the walk from the top
cannot reach is appended rather than dropped, so it stays pickable as
it was before.

Closes #1

(cherry picked from commit ea03406646062359f74e16ad8a8aed074b4dc409)

web/src/views/mail/MailboxPicker.tsx

@@ -5,6 +5,7 @@ import { Dialog } from "@/ui/dialog";
 import type { Id, Mailbox } from "@/jmap/types";
 import { t } from "@/lib/i18n";
 import { mailboxDisplayPath } from "@/lib/mailbox/mailboxName";
+import { treeOrder } from "@/lib/mailbox/folderOrder";
 
 /**
  * @param need which right a folder has to grant to be worth offering.
@@ -24,10 +25,11 @@ export function MailboxPicker({ title, onClose, onPick, exclude, need = "mayAddI
   const [q, setQ] = useState("");
   const [active, setActive] = useState(0);
   const list = useMemo(() => {
-    const all = Object.values(mailboxes)
+    // The sidebar's order, not A–Z by path: a folder dragged into place has to
+    // be found in the same place here.
+    const all = treeOrder(mailboxes)
       .filter((m) => !exclude?.includes(m.id) && m.myRights[need] && (!allow || allow(m.id)))
-      .map((m) => ({ m, path: mailboxDisplayPath(m, mailboxes), pick: () => onPick(m.id) }))
-      .sort((a, b) => (a.m.role === "inbox" ? -1 : b.m.role === "inbox" ? 1 : a.path.localeCompare(b.path)));
+      .map((m) => ({ m, path: mailboxDisplayPath(m, mailboxes), pick: () => onPick(m.id) }));
     const rows: { m: Mailbox | null; path: string; pick: () => void }[] = root ? [{ m: null, path: root.label, pick: root.onPick }, ...all] : all;
     const ql = q.trim().toLowerCase();
     return ql ? rows.filter((x) => x.path.toLowerCase().includes(ql)) : rows;

web/src/views/mail/__tests__/move-picker-order.test.tsx

@@ -0,0 +1,62 @@
+import { act } from "react";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { MailboxPicker } from "../MailboxPicker";
+import { useMail } from "@/store/mail";
+import type { Mailbox, MailboxRole } from "@/jmap/types";
+
+(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
+
+/**
+ * The move-to picker (v) lists folders in the sidebar's order (#1 on GitLab).
+ *
+ * It used to sort A–Z by path, so a folder dragged into place in the sidebar
+ * turned up somewhere else here. The ordering has its own tests in
+ * lib/mailbox; these check what the dialog actually shows.
+ */
+
+window.matchMedia = ((q: string) => ({ matches: false, media: q, addEventListener() {}, removeEventListener() {} })) as unknown as typeof window.matchMedia;
+
+const rights = { mayReadItems: true, mayAddItems: true, mayRemoveItems: true, maySetSeen: true, maySetKeywords: true, mayCreateChild: true, mayRename: true, mayDelete: true, maySubmit: true };
+const box = (id: string, name: string, parentId: string | null, role: MailboxRole = null, sortOrder = 0): Mailbox => ({
+  id, name, parentId, role, sortOrder, totalEmails: 0, unreadEmails: 0, totalThreads: 0, unreadThreads: 0, myRights: rights, isSubscribed: true,
+});
+
+/** Ordered by hand in the sidebar: Zeta dragged to the top, Alpha to the bottom. */
+const MAILBOXES = {
+  inbox: box("inbox", "Inbox", null, "inbox", 10),
+  zeta: box("zeta", "Zeta", null, null, 20),
+  sent: box("sent", "Sent", null, "sent", 30),
+  work: box("work", "Work", null, null, 40),
+  clients: box("clients", "Clients", "work"),
+  trash: box("trash", "Deleted Items", null, "trash", 50),
+  alpha: box("alpha", "Alpha", null, null, 60),
+};
+
+describe("the move-to picker", () => {
+  let host: HTMLDivElement;
+  let root: Root;
+  const rows = () => Array.from(document.querySelectorAll('[role="option"]')).map((r) => r.querySelector(".grow")?.textContent);
+
+  function open(props: Partial<Parameters<typeof MailboxPicker>[0]> = {}) {
+    act(() => root.render(<MailboxPicker title="Move to…" onClose={() => {}} onPick={() => {}} {...props} />));
+  }
+
+  beforeEach(() => {
+    useMail.setState({ mailboxes: MAILBOXES, mailboxesLoaded: true });
+    host = document.createElement("div");
+    document.body.appendChild(host);
+    root = createRoot(host);
+  });
+  afterEach(() => { act(() => root.unmount()); host.remove(); });
+
+  it("lists folders in the order they were dragged into, not A–Z", () => {
+    open();
+    expect(rows()).toEqual(["Inbox", "Zeta", "Sent", "Work", "Work / Clients", "Deleted Items", "Alpha"]);
+  });
+
+  it("keeps that order for the folders left after excluding one", () => {
+    open({ exclude: ["work"] });
+    expect(rows()).toEqual(["Inbox", "Zeta", "Sent", "Work / Clients", "Deleted Items", "Alpha"]);
+  });
+});