diff: the focus hook answers to either name the engine stamps on its elements

mods/diff/hooks/names/index.ts

@@ -3,7 +3,7 @@ export * from './command-name.js'
 export * from './keys'
 export * from './pane-id.js'
 export * from './pane-title.js'
-export * from './plugin-name.js'
+export * from './plugin-names.js'
 export * from './texts'
 
 export * as default from '.'

mods/diff/hooks/names/plugin-name.ts

@@ -1,5 +0,0 @@
-/**
- * The plugin's own name, as the engine stamps it on the elements its render
- * hooks draw (`ui.press`, `ui.focus`).
- */
-export const PLUGIN_NAME = 'diff'

mods/diff/hooks/names/plugin-names.ts

@@ -0,0 +1,6 @@
+/**
+ * The names the engine may stamp on the elements this plugin's render hooks
+ * draw (`ui.press`, `ui.focus`): its own, and the one a build that carries
+ * it registers it under.
+ */
+export const PLUGIN_NAMES = ['diff', 'cc-plugin-diff'] as const

mods/diff/hooks/register.ts

@@ -833,7 +833,7 @@ export function register(on: On) {
     return result
   })
 
-  on('ui.focus', { plugin: Names.PLUGIN_NAME }, ($, e, next) => {
+  on('ui.focus', { plugin: Names.PLUGIN_NAMES }, ($, e, next) => {
     const isListed =
       model.placement === 'inline' && model.dialogView === 'list' && host
 

mods/diff/tests/fixtures/ring-onto.ts

@@ -7,12 +7,13 @@ import { PANE } from './pane.js'
  * elements, as the engine raises it before the ring moves.
  *
  * @param key the element's key
+ * @param plugin the name the engine stamped on the element
  * @returns the `ui.focus` input
  */
-export const ringOnto = (key: string): UiFocusInput => ({
+export const ringOnto = (key: string, plugin = 'diff'): UiFocusInput => ({
   component: 'Pane',
   requestId: PANE.requestId,
-  plugin: 'diff',
+  plugin,
   element: key,
   origin: { kind: 'person' },
 })

mods/diff/tests/views.test.ts

@@ -200,6 +200,24 @@ describe('views', () => {
     expect(walked).not.toContain('file0.ts')
   })
 
+  test('the walk follows under the name a build registers', async ($, on) => {
+    const world = Fixtures.inRepository(on, Fixtures.MANY_FILES)
+
+    await $.session.start(Fixtures.SESSION)
+    await $.command.run(Fixtures.DIALOG_DIFF)
+    await world.clock.advance(Fixtures.SETTLE_MS)
+    await $.ui.render(Fixtures.INLINE_PANE)
+
+    expect(
+      await $.ui.focus(Fixtures.ringOnto('file:file3.ts', 'cc-plugin-diff')),
+    ).toEqual({})
+
+    expect(
+      world.focused.map(focus => focus.element),
+      'its row once centred',
+    ).toEqual(['file:file2.ts'])
+  })
+
   test('off fullscreen, the walk stops at the last file', async ($, on) => {
     const world = Fixtures.inRepository(on, Fixtures.MANY_FILES)