fix: fall back to structured-clone for RPC error envelopes

Author: baseballyama

devframe/packages/devframe/src/rpc/transports/ws-client.ts

@@ -84,7 +84,11 @@ export function createWsRpcChannel(options: WsRpcChannelOptions): ChannelOptions
         method = pendingRequestMethods.get(msg.i)
         pendingRequestMethods.delete(msg.i)
       }
-      const useJson = !!method && definitions.get(method)?.jsonSerializable === true
+      // `jsonSerializable` describes the *result* shape, not the error path.
+      // Error envelopes (`{ t: 's', i, e }`) carry a thrown value — fall back
+      // to structured-clone so they round-trip instead of crashing the serializer.
+      const isErrorResponse = msg.t !== 'q' && msg.e !== undefined
+      const useJson = !isErrorResponse && !!method && definitions.get(method)?.jsonSerializable === true
       if (useJson)
         return strictJsonStringify(msg, method ?? '')
       return `${STRUCTURED_CLONE_PREFIX}${structuredCloneStringify(msg)}`

devframe/packages/devframe/src/rpc/transports/ws-server.ts

@@ -127,7 +127,11 @@ export function attachWsRpcTransport<
           method = pendingRequestMethods.get(msg.i)
           pendingRequestMethods.delete(msg.i)
         }
-        const useJson = !!method && definitions.get(method)?.jsonSerializable === true
+        // `jsonSerializable` describes the *result* shape, not the error path.
+        // Error envelopes (`{ t: 's', i, e }`) carry a thrown value — fall back
+        // to structured-clone so they round-trip instead of crashing the serializer.
+        const isErrorResponse = msg.t !== 'q' && msg.e !== undefined
+        const useJson = !isErrorResponse && !!method && definitions.get(method)?.jsonSerializable === true
         if (useJson)
           return strictJsonStringify(msg, method ?? '')
         return `${STRUCTURED_CLONE_PREFIX}${structuredCloneStringify(msg)}`

devframe/packages/devframe/src/rpc/transports/ws.test.ts

@@ -52,4 +52,32 @@ describe('devtools rpc', () => {
 
     expect(await server.broadcast.$call('hey', 'server')).toEqual(expect.arrayContaining(['hey server, I\'m client 1', 'hey server, I\'m client 2']))
   })
+
+  // Regression: a `jsonSerializable: true` RPC that throws used to crash the
+  // WS serializer with DF0020 because the error envelope was strict-JSON-encoded
+  // alongside the result path.
+  it('returns a rejection (not a serialization crash) when a jsonSerializable RPC throws', async () => {
+    const PORT = 3334
+    const HOST = '127.0.0.1'
+    const WS_URL = `ws://${HOST}:${PORT}`
+
+    const serverFunctions = {
+      explode: async () => {
+        throw new Error('boom')
+      },
+    }
+
+    const definitions = new Map<string, { jsonSerializable?: boolean }>([
+      ['explode', { jsonSerializable: true }],
+    ])
+
+    const server = createRpcServer<Record<string, never>, typeof serverFunctions>(serverFunctions)
+    attachWsRpcTransport(server, { port: PORT, host: HOST, definitions: definitions as any })
+
+    const client = createRpcClient<typeof serverFunctions, Record<string, never>>({}, {
+      channel: createWsRpcChannel({ url: WS_URL, definitions: definitions as any }),
+    })
+
+    await expect(client.$call('explode')).rejects.toThrow(/boom/)
+  })
 })