[NayNay] Signing Fix: Message too long error (#412)

src/signing/index.ts

@@ -1,4 +1,5 @@
 import { ApiPromise } from '@polkadot/api'
+import { hexAddPrefix } from '@polkadot/util'
 import { Signer } from '../keys/types/internal'
 import { defaultAdapters } from './adapters/default'
 import { Adapter } from './adapters/types'
@@ -364,8 +365,15 @@ export default class SignatureRequestManager {
       // define keygroups see issue#380 https://github.com/entropyxyz/sdk/issues/380
       this.#keyGroups[i] = keyGroup
       // omg polkadot type gen is a head ache
+      // 
+      // If the Message being signed is too long the sigRequestHash is then converted to a number
+      // so large that the resulting parsed value of parseInt(sigRequest, 16) would return Infinity.
+      // Using BigInt instead solves the Infinity issue, and now allows messages of any length to be
+      // signed.
+      //
+      const sigToConvert = hexAddPrefix(sigRequest)
       // @ts-ignore: next line
-      const index = parseInt(sigRequest, 16) % keyGroup.unwrap().length
+      const index = Number(BigInt(sigToConvert) % BigInt(keyGroup.unwrap().length))
       if (isNaN(index)) {
         throw new Error(`when calculating the index for choosing a validator got: NaN`)
       }

tests/sign.test.ts

@@ -60,6 +60,32 @@ test('Sign', async (t) => {
   t.end()
 })
 
+test('Sign: Long Message', async t => {
+  const { run, entropy } = await setupTest(t)
+
+  const dummyLongMessage = `Deep Divide Have Grass Blessed Greater Replenish
+  Tree Days You're Seed Earth Above
+  Blessed beginning god give air above green. God have. Midst. Moved made divided seasons light in be place years above gathered. Days which day waters.
+  
+  Seasons
+  Given one moving darkness appear. You Lesser moving saw. They're divided rule air his seasons. Fifth lights be gathering upon gathering gathering darkness, over. Whales.
+  
+  Adding some symbols for good measure: #$@%@#$@#%#@`;
+
+  const signature = await run(
+    'sign',
+    entropy.signWithAdaptersInOrder({
+      msg: { msg: dummyLongMessage },
+      order: ['deviceKeyProxy'],
+    })
+  )
+
+  t.true(signature && signature.length > 32, 'signature has some body!')
+  signature && console.log(signature)
+
+  t.end()
+})
+
 test('Sign: custom signatureVerifyingKey', async (t) => {
   const run = promiseRunner(t)
 
@@ -171,4 +197,4 @@ test('Sign:issue#380', async (t) => {
 
 
   t.end()
-})
+})