swarm-ui: a todo switched from clear to upsert drops its prefix flag

docs/swarm/ui.md

@@ -258,9 +258,12 @@ Edits stay in a draft until **save**, which sends the whole flows document with
 the revision the editor read. **discard edits** goes back to the saved flow and
 **delete flow** removes it, after a confirmation. If someone changed the flows
 elsewhere in the meantime, the controller turns the save down as stale, and the
-editor offers to reload and drop your edits, or to keep them on top of the
-latest. For any other refusal the editor shows the controller's own message.
-The router runs a saved flow from its next event.
+editor offers to reload and drop your edits, or to keep them and replace this
+flow's latest version with them. For any other refusal the editor shows the
+controller's own message. The router runs a saved flow from its next event.
+
+Closing or reloading the tab with unsaved edits asks first. Leaving through a
+link in the app, or the browser's back button, drops the draft without asking.
 
 ### Sending a message to an agent
 

frontend/packages/swarm-ui/src/pages/notifications/FlowDraft.ts

@@ -200,6 +200,20 @@ export function reparent(
   };
 }
 
+// A todo with its op switched. A clear carries no text, and only a clear may
+// be a prefix, so each is reset where the new op has no place for it.
+export function withOp(
+  node: Extract<FlowNode, { kind: "todo" }>,
+  op: "upsert" | "clear",
+): Extract<FlowNode, { kind: "todo" }> {
+  return {
+    ...node,
+    op,
+    text: op === "clear" ? "" : node.text,
+    prefix: op === "clear" ? node.prefix : false,
+  };
+}
+
 // The node with `next.id` swapped for `next`. A node keeps its place and its
 // kind-class: the source stays the source, and nothing with children becomes
 // a todo.

frontend/packages/swarm-ui/src/pages/notifications/FlowEditorPage.tsx

@@ -185,7 +185,7 @@ export function FlowEditorPage({
             reload and drop my edits
           </Button>
           <Button onClick={() => void load(true)}>
-            keep my edits on top of the latest
+            keep my edits (replaces this flow's latest version)
           </Button>
         </div>
       ) : null}

frontend/packages/swarm-ui/src/pages/notifications/NodeInspector.tsx

@@ -16,6 +16,7 @@ import {
   replaceNode,
   type Edit,
   type Limits,
+  withOp,
 } from "./FlowDraft.js";
 import {
   kindValues,
@@ -237,14 +238,7 @@ function TodoFields({
         label="op"
         value={node.op}
         options={opList}
-        onChange={(op) =>
-          onChange({
-            ...node,
-            op: op as TodoNode["op"],
-            // A clear carries no text.
-            text: op === "clear" ? "" : node.text,
-          })
-        }
+        onChange={(op) => onChange(withOp(node, op as TodoNode["op"]))}
       />
       <SelectField
         id={`${keyPrefix}-to-kind`}

frontend/packages/swarm-ui/test/flow-draft.test.mjs

@@ -21,6 +21,7 @@ import {
   subtreeIds,
   withFlow,
   withoutFlow,
+  withOp,
 } from "../src/pages/notifications/FlowDraft.ts";
 
 const todo = (id) => ({
@@ -156,6 +157,16 @@ test("replaceNode keeps the place and the kind class", () => {
   assert.equal(replaceNode(f, todo("nope")).ok, false);
 });
 
+test("withOp drops what the new op has no place for", () => {
+  const clearing = { ...todo("t"), op: "clear", prefix: true, text: "" };
+  const up = withOp(clearing, "upsert");
+  assert.equal(up.op, "upsert");
+  assert.equal(up.prefix, false, "only a clear may be a prefix");
+  const back = withOp({ ...todo("t"), prefix: false }, "clear");
+  assert.equal(back.text, "", "a clear carries no text");
+  assert.equal(withOp(clearing, "clear").prefix, true, "kept on a clear");
+});
+
 test("new ids do not collide", () => {
   const f = flow();
   assert.equal(newNodeId(f, "match"), "match1");