host: six bounds on text another home supplied cut on code points, not UTF-16 units

changelog.d/1979-external-text-bounds.fixed.md

@@ -0,0 +1 @@
+Six bounds on text another home or another person supplied no longer cut on UTF-16 units ([#1979](https://github.com/ThinkFlowLab/FlyBot/issues/1979)): a connector item name (80), a role label another home set on a face-room seat (80), a cross-home group name (200), a capability description from a peer server (2,000), a remote home's own error text (157) and an abbreviated remote reply (80) used a bare `slice`, so a bound that landed between the halves of a surrogate pair produced a lone high surrogate — read as U+FFFD by any encoder and shown to the owner that way. Each now goes through the shared `cut`, which keeps the longest prefix that stops before a split pair within the same budget; the error preview's `…` and the reply's trailing-period strip still apply to the cut value.

core/src/host/capabilities.js

@@ -1,6 +1,7 @@
 import { createHash } from 'node:crypto'
 import { RESERVED_NAMES } from './connectors.js'
 import { ownEntry, retiredBot } from './store.js'
+import { cut } from './text.js'
 
 const MCP_CLIENT = '@deepseek-ai/dsh-mcp-client'
 const NAME = /^[a-z][a-z0-9]*(?:-[a-z0-9]+)*$/
@@ -94,7 +95,7 @@ export function install(rt) {
     const item = {
       name,
       kind,
-      description: String(body.description ?? '').trim().slice(0, 2000),
+      description: cut(String(body.description ?? '').trim(), 2000).text,
       createdBy: previous?.createdBy ?? (ui ? null : botId),
       createdAt: previous?.createdAt ?? now,
       updatedAt: now,

core/src/host/connectors.js

@@ -20,6 +20,7 @@ import { randomUUID } from 'node:crypto'
 import { createNotifier } from './notify.js'
 import { APP_SECRET_SECRET, appCredentials, createInbound } from './feishu-inbound.js'
 import { createFeishuTransport } from './feishu-sdk.js'
+import { cut } from './text.js'
 
 export const GITHUB = 'github'
 export const GITHUB_SECRET = 'GITHUB_TOKEN'
@@ -200,7 +201,7 @@ export async function composioSearchApps(apiKey, { api = COMPOSIO_DEFAULTS.api,
   for (const item of items) {
     const slug = typeof item?.slug === 'string' ? item.slug.toLowerCase() : ''
     if (!APP_SLUG.test(slug) || found.has(slug)) continue
-    const name = typeof item.name === 'string' && item.name.trim() !== '' ? item.name.trim().slice(0, 80) : slug
+    const name = typeof item.name === 'string' && item.name.trim() !== '' ? cut(item.name.trim(), 80).text : slug
     found.set(slug, { slug, name })
   }
   return [...found.values()].slice(0, MAX_FOUND)

core/src/host/face-lead.js

@@ -3,6 +3,7 @@
 // field, it is the first Bot of the creator's home that joined. The lead writes the one plan and
 // gives out the parts; every other Bot does only its part. Pure: the room record in, text out.
 import { cleanPeerName, ownerNameOf } from '../shared/remote-label.js'
+import { cut } from './text.js'
 
 const ROLE_MAX = 80
 // Same as room-membership.js currentParticipants (kept here so the two modules do not import each other).
@@ -11,12 +12,12 @@ const handleKey = handle => String(handle ?? '').trim().replace(/^@+/, '').toLow
 
 // A role label another home set: one line of plain text, no markup or @, capped.
 export function cleanRoleLabel(value) {
-  return String(value ?? '')
+  const line = String(value ?? '')
     .replace(/[\u0000-\u001f\u007f-\u009f\u2028\u2029]/g, ' ')
     .replace(/[[\]"`<>@]/g, '')
     .replace(/\s+/g, ' ')
     .trim()
-    .slice(0, ROLE_MAX)
+  return cut(line, ROLE_MAX).text
 }
 
 // What the host keeps on room.face.lead: the handle every home follows, whether the creator picked

core/src/host/project-team.js

@@ -14,6 +14,7 @@
 // dossier panel draws, so it carries exactly those keys and nothing that names an owner, a working
 // folder or a stored secret.
 import { rolesOf } from './project-board.js'
+import { cut } from './text.js'
 
 export const DOSSIER_LIMITS = { persona: 4000, memoryHead: 4000, topics: 64, skills: 64, rooms: 32, name: 200, role: 120, model: 200, color: 64 }
 
@@ -45,7 +46,7 @@ export function install(rt) {
   const roomsOf = (bot, project) => Object.values(rt.state?.rooms ?? {})
     .filter(room => room !== null && typeof room === 'object' && Array.isArray(room.members) && room.members.includes(bot.id))
     .filter(room => rt.projectOfMember?.('group', room.id)?.id === project.id)
-    .map(room => ({ id: text(room.id), name: text(room.name).slice(0, 200) }))
+    .map(room => ({ id: text(room.id), name: cut(text(room.name), 200).text }))
     .slice(0, DOSSIER_LIMITS.rooms)
 
   const rowOf = (botId, project) => {

core/src/host/remote-chat.js

@@ -15,6 +15,7 @@ import { createUserMessage, LlmAdapter } from '@deepseek-ai/dsh-llm'
 import { SOURCE_KIND } from './constants.js'
 import { cleanName, fenceUntrusted } from './delivery.js'
 import { isHomeLevelRemote, normRemoteHandle } from '../shared/remote-label.js'
+import { cut } from './text.js'
 
 export const REMOTE_PROVIDER = 'flybot-remote'
 export const REMOTE_FORM = 'remote-chat'
@@ -27,7 +28,7 @@ const textOf = content => (Array.isArray(content) ? content.filter(block => bloc
 // English line with a next step; never dump `Bot Social send_as_member: …`.
 export function notSentLine(error) {
   const raw = String(error?.message ?? error ?? '').replace(/\s+/g, ' ').trim()
-  if (/^Not sent:/i.test(raw)) return raw.length > 160 ? `${raw.slice(0, 157)}…` : raw
+  if (/^Not sent:/i.test(raw)) return raw.length > 160 ? `${cut(raw, 157).text}…` : raw
   const body = raw.replace(/^Bot Social\s+[A-Za-z0-9_.-]+:\s*/i, '').trim()
   const blob = `${raw} ${error?.code ?? ''}`
   if (/paused|turn budget|loop detected|emergency stop/i.test(blob)) {
@@ -73,7 +74,7 @@ export function notSentLine(error) {
     return 'Not sent: Bot Social did not answer. Try again.'
   }
   // One "Try again." only: an earlier layer may already have said it (#954), and two reads as a stutter.
-  const short = (body || raw).slice(0, 80).replace(/\.$/, '').replace(/\.?\s*Try again\.?$/i, '').replace(/\.$/, '')
+  const short = cut(body || raw, 80).text.replace(/\.$/, '').replace(/\.?\s*Try again\.?$/i, '').replace(/\.$/, '')
   if (!short || /^[a-z0-9_]+$/i.test(short)) {
     return 'Not sent: the message could not leave. Try again.'
   }

core/test/capabilities.test.js

@@ -447,3 +447,17 @@ test('a key for all Bots reaches a shared Bot\'s capability; a key scoped to oth
   assert.equal(rt.capabilityStatusesView().worker.echo.state, 'error')
   assert.equal(rt.capabilityStatusesView().chief.echo.state, 'ready')
 })
+
+// #1979: a capability description comes from a peer server, and its 2000-unit bound must not end
+// on the first half of a surrogate pair.
+test('a capability description is cut at 2000 without splitting an emoji', async t => {
+  const env = await setup()
+  t.after(() => env.dispose())
+  const description = 'a'.repeat(1999) + '😀' + 'tail'
+  await env.rt.capabilitySave({ name: 'echo', kind: 'skill', description, content: 'Do the work.' }, { ui: true })
+  const kept = env.rt.state.capabilities.items.echo.description
+  assert.equal(kept.isWellFormed(), true, 'the stored description is well formed, never a lone high surrogate')
+  assert.equal(kept, 'a'.repeat(1999), 'the 2000th unit was the first half of the pair, so the pair is dropped, not split')
+  assert.ok(description.startsWith(kept), 'a code-point prefix of the description the peer sent')
+  assert.ok(kept.length <= 2000, 'the budget of 2000 UTF-16 units is unchanged')
+})

core/test/connectors.test.js

@@ -943,3 +943,17 @@ test('the Connectors page searches apps with the pasted key before connecting (n
   assert.equal(github.ok, false)
   assert.match(github.error.message, /no apps to pick/)
 })
+
+// #1979: a connector item name is text the connector side supplies, and its 80-unit bound must not
+// end on the first half of a surrogate pair: that value reaches the owner's screen as U+FFFD.
+test('a Composio app name cut at 80 does not split an emoji', async () => {
+  const key = composioKey()
+  const name = 'a'.repeat(79) + '😀' + 'tail'
+  const found = await composioSearchApps(key, { fetch: async () => answer(200, { items: [{ slug: 'gmail', name }] }) })
+  assert.equal(found.length, 1, 'the app is still listed')
+  const kept = found[0].name
+  assert.equal(kept.isWellFormed(), true, 'the kept name is well formed, never a lone high surrogate')
+  assert.equal(kept, 'a'.repeat(79), 'the 80th unit was the first half of the pair, so the pair is dropped, not split')
+  assert.ok(name.startsWith(kept), 'a code-point prefix of the name Composio supplied')
+  assert.ok(kept.length <= 80, 'the budget of 80 UTF-16 units is unchanged')
+})

core/test/face-lead.test.js

@@ -0,0 +1,15 @@
+// #1979: a role label another home set on a face-room seat is bounded at 80. A cut that lands between
+// the halves of a surrogate pair returns a lone high surrogate, which reaches a UTF-8 encoder as
+// U+FFFD, so the bound goes through `cut()` and keeps a well-formed code-point prefix.
+import assert from 'node:assert/strict'
+import { test } from 'node:test'
+import { cleanRoleLabel } from '../src/host/face-lead.js'
+
+test('a role label another home set is cut at 80 without splitting an emoji', () => {
+  const label = 'a'.repeat(79) + '😀' + 'tail'
+  const cleaned = cleanRoleLabel(label)
+  assert.equal(cleaned.isWellFormed(), true, 'the cleaned label is well formed, never a lone high surrogate')
+  assert.equal(cleaned, 'a'.repeat(79), 'the 80th unit was the first half of the pair, so the pair is dropped, not split')
+  assert.ok(label.startsWith(cleaned), 'a code-point prefix of the label another home supplied')
+  assert.ok(cleaned.length <= 80, 'the budget of 80 UTF-16 units is unchanged')
+})

core/test/project-team.test.js

@@ -173,3 +173,18 @@ test('project-team reads with the project-read class of caller, including a sign
   const unknown = await callAs('project-team', { id: 'project-none' }, 'tok-owner')
   assert.deepEqual(unknown.value.rows, [], 'an unknown Project answers no rows instead of an error')
 })
+
+// #1979: a group name is text another home supplied, and its 200-unit bound must not end on the
+// first half of a surrogate pair.
+test('project-team cuts a room name from another home at 200 without splitting an emoji', async (t) => {
+  const { callAs, rt, stop } = await start()
+  t.after(stop)
+  const name = 'a'.repeat(199) + '😀' + 'tail'
+  rt.state.rooms.r1.name = name
+  const rows = (await callAs('project-team', { id: 'project-1' })).value.rows
+  const kept = rows[0].rooms.find(room => room.id === 'r1').name
+  assert.equal(kept.isWellFormed(), true, 'the group name is well formed, never a lone high surrogate')
+  assert.equal(kept, 'a'.repeat(199), 'the 200th unit was the first half of the pair, so the pair is dropped, not split')
+  assert.ok(name.startsWith(kept), 'a code-point prefix of the group name')
+  assert.ok(kept.length <= 200, 'the budget of 200 UTF-16 units is unchanged')
+})

core/test/remote-chat.test.js

@@ -304,3 +304,29 @@ test('a reply typed into a feishu chat leaves on the Feishu webhook (#1266)', as
   assert.equal(said, '', 'nothing is drawn for a send that left')
   assert.deepEqual(posts, [['https://open.feishu.cn/open-apis/bot/v2/hook/abc', 'the answer']])
 })
+
+// #1979: the remote home's own error text is cut at 157 units and ends in "…"; a cut that lands
+// between the halves of a surrogate pair hands the owner a lone high surrogate.
+test('#1979: a long remote error keeps a well-formed 157-unit tail before the ellipsis', () => {
+    const raw = 'Not sent: ' + 'a'.repeat(146) + '😀' + 'tail';
+    assert.ok(raw.length > 160, 'the long-line branch only runs past 160 units');
+    const line = notSentLine(new Error(raw));
+    assert.equal(line.isWellFormed(), true, 'the preview is well formed, never a lone high surrogate');
+    assert.ok(line.endsWith('…'), 'the long line still ends in the ellipsis');
+    const kept = line.slice(0, -1);
+    assert.equal(kept, 'Not sent: ' + 'a'.repeat(146), 'the pair at the bound is dropped, not split');
+    assert.ok(raw.startsWith(kept), 'a code-point prefix of what the remote home wrote');
+    assert.ok(kept.length <= 157, 'the budget of 157 UTF-16 units is unchanged');
+});
+
+// #1979: a remote reply is abbreviated to 80 units before the trailing-period strip, so an emoji at
+// the bound must not leave a lone high surrogate in the sentence the owner reads.
+test('#1979: an abbreviated remote reply is well formed at 80 units', () => {
+    const body = 'the remote said ' + 'a'.repeat(63) + '😀' + 'tail';
+    const kept = 'the remote said ' + 'a'.repeat(63);
+    assert.equal(kept.length, 79, 'the pair starts at unit 79, so a plain slice(0, 80) keeps half of it');
+    const line = notSentLine(new Error('Bot Social send_as_member: ' + body));
+    assert.equal(line.isWellFormed(), true, 'the sentence is well formed, never a lone high surrogate');
+    assert.equal(line, 'Not sent: ' + kept + '. Try again.', 'the pair at the bound is dropped, not split');
+    assert.ok(body.startsWith(kept), 'a code-point prefix of the reply');
+});