chore: add back diagnostic

Author: posva

docs/content/6.errors/DF0077.md

@@ -0,0 +1,26 @@
+---
+title: 'DF0077: In-Page Channel Function Not Registered'
+description: 'An in-page channel call names a function that is not registered on its endpoint.'
+---
+
+## Message
+
+> In-page channel function "{name}" is not registered on this endpoint.
+
+## Cause
+
+An in-page channel call named a function absent from the receiving endpoint's required `functions` option.
+
+## Example
+
+```ts
+await channel.call('missing' as any) // ✗ throws DF0077
+```
+
+## Fix
+
+Declare the function in the receiving endpoint's protocol side and `functions` option.
+
+## Source
+
+- [`packages/devframe/src/in-page-channel/internal.ts`](https://github.com/devframes/devframe/blob/main/packages/devframe/src/in-page-channel/internal.ts): `createLocalFunctionRegistry().resolve()` throws this when no local function definition matches the call name.

docs/content/6.errors/index.md

@@ -83,6 +83,7 @@ Emitted by `devframe`: the framework-neutral host, RPC, streaming, assets, servi
 | [DF0074](/errors/DF0074) | error | JSON-Render Schema Is Asynchronous |
 | [DF0075](/errors/DF0075) | warn | No RPC Transport On This Runtime |
 | [DF0076](/errors/DF0076) | error | WebSocket Upgrade Unsupported On This Runtime |
+| [DF0077](/errors/DF0077) | error | In-Page Channel Function Not Registered |
 
 ## Hub: context & lifecycle (DF80xx)
 

packages/devframe/src/in-page-channel/diagnostics.ts

@@ -0,0 +1,11 @@
+import { defineDiagnostics } from 'devframe/utils/nostics'
+
+export const diagnostics = /* #__PURE__ */ defineDiagnostics({
+  docsBase: 'https://devfra.me/errors',
+  codes: {
+    DF0077: {
+      why: (p: { name: string }) => `In-page channel function "${p.name}" is not registered on this endpoint.`,
+      fix: 'Declare the function in this endpoint\'s `functions` option.',
+    },
+  },
+})

packages/devframe/src/in-page-channel/in-page-channel.test.ts

@@ -229,13 +229,16 @@ describe('in-page channel over bring-your-own ports', () => {
     }
   })
 
-  it('rejects calls to unknown functions', async () => {
+  it('rejects calls to unknown functions with a coded diagnostic', async () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
     const { panel, dispose } = createLinkedPair()
     try {
-      await expect(panel.call('missing' as any)).rejects.toThrow(/not found/)
+      await expect(panel.call('missing' as any)).rejects.toThrow('In-page channel function "missing" is not registered')
+      expect(warn).toHaveBeenCalledWith(expect.stringContaining('[DF0077]'))
     }
     finally {
       dispose()
+      warn.mockRestore()
     }
   })
 

packages/devframe/src/in-page-channel/internal.ts

@@ -4,6 +4,7 @@ import type { RpcArgsSchema } from '../rpc/types'
 import type { InPageChannelControlFrame } from './protocol'
 import type { InPageFunctionDefinitionAny } from './types'
 import { createBirpc } from 'birpc'
+import { diagnostics } from './diagnostics'
 import { isControlFrame } from './protocol'
 
 /**
@@ -162,6 +163,8 @@ export function channelMethod(kind: 'function' | 'event', name: string): string
   return `devframe:in-page:${kind}:${name}`
 }
 
+const FUNCTION_METHOD_PREFIX = channelMethod('function', '')
+
 /**
  * An endpoint's local function table, resolved by name when the remote side
  * calls in. Each handler is wrapped with the receive pipeline: deserialize
@@ -196,8 +199,14 @@ export function createLocalFunctionRegistry(codec: InPageChannelSerialization):
     resolve(name) {
       const definition = definitions.get(name)
       const registered = listeners.get(name)
-      if (!definition && !registered?.size)
+      if (!definition && !registered?.size) {
+        if (name.startsWith(FUNCTION_METHOD_PREFIX)) {
+          return () => {
+            throw diagnostics.DF0077({ name: name.slice(FUNCTION_METHOD_PREFIX.length) })
+          }
+        }
         return undefined
+      }
       return async (...rawArgs: unknown[]) => {
         const args = codec.deserialize ? rawArgs.map(codec.deserialize) : rawArgs
         if (definition?.jsonSerializable)