fix(admin): serialize unset config fields using their defaults

web/src/screens/admin-screen.test.tsx

@@ -81,4 +81,30 @@ describe("admin workflows", () => {
     expect(adminApi.login).toHaveBeenCalledWith("new password");
     expect(replace).toHaveBeenCalledWith("/admin/");
   });
+
+  it("renders the real error message when setup fails", async () => {
+    adminApi.session.mockResolvedValue(false);
+    adminApi.getConfig.mockRejectedValueOnce(new Error("setup config unreachable"));
+    const view = renderAdmin("/admin/setup");
+    const inputs = view.container.querySelectorAll('input[type="password"]');
+    const token = "t".repeat(32);
+    await userEvent.type(inputs[0], token);
+    await userEvent.type(inputs[1], "new password");
+    await userEvent.type(inputs[2], "new password");
+    await userEvent.click(screen.getByRole("button", { name: "Create admin" }));
+    expect(await screen.findByText("setup config unreachable")).toBeInTheDocument();
+  });
+
+  it("renders a fallback message for a non-Error setup rejection", async () => {
+    adminApi.session.mockResolvedValue(false);
+    adminApi.getConfig.mockRejectedValueOnce("boom");
+    const view = renderAdmin("/admin/setup");
+    const inputs = view.container.querySelectorAll('input[type="password"]');
+    const token = "t".repeat(32);
+    await userEvent.type(inputs[0], token);
+    await userEvent.type(inputs[1], "new password");
+    await userEvent.type(inputs[2], "new password");
+    await userEvent.click(screen.getByRole("button", { name: "Create admin" }));
+    expect(await screen.findByText("The admin setup request failed.")).toBeInTheDocument();
+  });
 });

web/src/screens/admin.test.ts

@@ -7,7 +7,51 @@ describe("admin config serialization", () => {
     expect(result).toEqual({ general: { port: 8334, name: "Files" }, connections: [{ label: "Local", type: "local" }] });
   });
 
+  it("uses effective defaults for unset fields", () => {
+    const result = serializeConfig({
+      general: {
+        port: { label: "port", type: "number", value: null, default: 45673 },
+        force_ssl: { label: "force_ssl", type: "boolean", value: null, default: true },
+        display_hidden: { label: "display_hidden", type: "boolean", value: null, default: false },
+        name: { label: "name", type: "text", value: null, default: "Filestash" },
+        host: { label: "host", type: "text", value: null, default: null },
+      },
+    });
+
+    expect(result).toEqual({ general: { port: 45673, force_ssl: true, display_hidden: false, name: "Filestash" } });
+  });
+
   it("rejects invalid numeric values before saving", () => {
     expect(() => serializeConfig({ port: { label: "Port", type: "number", value: "nope" } })).toThrow("Port must be a valid number");
   });
+
+  it("omits number fields with no value and no default instead of inventing 0", () => {
+    const result = serializeConfig({ general: { port: { label: "port", type: "number", value: null } } });
+    expect(result).toEqual({ general: {} });
+  });
+
+  it("preserves a falsy-but-set boolean value over a truthy default", () => {
+    const result = serializeConfig({ general: { force_ssl: { label: "force_ssl", type: "boolean", value: false, default: true } } });
+    expect(result).toEqual({ general: { force_ssl: false } });
+  });
+
+  it("preserves a zero numeric value over a non-zero default", () => {
+    const result = serializeConfig({ general: { retries: { label: "retries", type: "number", value: 0, default: 99 } } });
+    expect(result).toEqual({ general: { retries: 0 } });
+  });
+
+  it("uses the default for an unset enable field", () => {
+    const result = serializeConfig({ general: { feature: { label: "feature", type: "enable", value: null, default: true } } });
+    expect(result).toEqual({ general: { feature: true } });
+  });
+
+  it("omits text/boolean fields with no value and no default", () => {
+    const result = serializeConfig({
+      general: {
+        host: { label: "host", type: "text", value: null, default: null },
+        force_ssl: { label: "force_ssl", type: "boolean", value: null, default: null },
+      },
+    });
+    expect(result).toEqual({ general: {} });
+  });
 });

web/src/screens/admin.tsx

@@ -37,15 +37,26 @@ export function serializeConfig(node: unknown): unknown {
     const o = node as Record<string, unknown>;
     if (typeof o.type === "string" && "value" in o) {
       if (o.type === "number") {
-        if (o.value === "" || o.value == null) return null;
+        if (o.value === "" || o.value == null) {
+          if (o.default == null) return undefined;
+          const number = typeof o.default === "number" ? o.default : Number(o.default);
+          if (!Number.isFinite(number)) throw new Error(`${String(o.label ?? "Number")} must be a valid number`);
+          return number;
+        }
         const number = typeof o.value === "number" ? o.value : Number(o.value);
         if (!Number.isFinite(number)) throw new Error(`${String(o.label ?? "Number")} must be a valid number`);
         return number;
       }
-      return o.value;
+      const effectiveValue = o.value ?? o.default;
+      if (effectiveValue == null) return undefined;
+      return effectiveValue;
     }
     const out: Record<string, unknown> = {};
-    for (const [k, v] of Object.entries(o)) out[k] = serializeConfig(v);
+    for (const [k, v] of Object.entries(o)) {
+      const serialized = serializeConfig(v);
+      if (serialized === undefined) continue;
+      out[k] = serialized;
+    }
     return out;
   }
   return node;
@@ -61,7 +72,7 @@ export function AdminScreen({ pathname }: { pathname: string }) {
   }
   if (session.isLoading) return <Centered label="Loading admin session" />;
   if (session.isError) {
-    return <Centered><Callout title="Could not check the admin session" variant="error"><div className="grid gap-3"><span>{(session.error as Error).message}</span><Button size="sm" variant="neutral" onClick={() => void session.refetch()}>Retry</Button></div></Callout></Centered>;
+    return <Centered><Callout title="Could not check the admin session" variant="error"><div className="grid gap-3"><span>{session.error instanceof Error ? session.error.message : "The admin session endpoint returned an error."}</span><Button size="sm" variant="neutral" onClick={() => void session.refetch()}>Retry</Button></div></Callout></Centered>;
   }
   if (!session.data) {
     return <AdminLogin onSuccess={() => queryClient.invalidateQueries({ queryKey: ["admin-session"] })} />;
@@ -119,7 +130,7 @@ function AdminSetup({ onDone }: { onDone: () => void }) {
             <Field label="Confirm password" htmlFor="admin-setup-confirm" error={confirm && confirm !== password ? "Passwords don't match" : undefined}>
               <Input id="admin-setup-confirm" type="password" value={confirm} onChange={(e) => setConfirm(e.target.value)} />
             </Field>
-            {setup.isError ? <Callout title="Setup failed" variant="error">Try again.</Callout> : null}
+            {setup.isError ? <Callout title="Setup failed" variant="error">{setup.error instanceof Error ? setup.error.message : "The admin setup request failed."}</Callout> : null}
             <Button type="submit" variant="aurora" disabled={!canSubmit || setup.isPending} loading={setup.isPending}>
               {setup.isPending ? "Setting up…" : "Create admin"}
             </Button>
@@ -259,7 +270,7 @@ function SettingsPanel() {
           {save.isSuccess ? "Saved" : "Save"}
         </Button>
       </div>
-      {save.isError ? <Callout title="Settings were not saved" variant="error"><div className="grid gap-3"><span>{(save.error as Error).message}</span><Button size="sm" variant="neutral" onClick={() => save.mutate()}>Retry</Button></div></Callout> : null}
+      {save.isError ? <Callout title="Settings were not saved" variant="error"><div className="grid gap-3"><span>{save.error instanceof Error ? save.error.message : "The admin save endpoint returned an error."}</span><Button size="sm" variant="neutral" onClick={() => save.mutate()}>Retry</Button></div></Callout> : null}
       {save.isSuccess ? <Callout title="Settings saved" variant="success">The current configuration was reloaded from the server.</Callout> : null}
       {Object.entries(tree).map(([category, node]) => (
         <Card key={category} elevated className="overflow-hidden">