fix: @helia/json.get throws if CID codec not JSON

Author: tabcat

packages/json/src/index.ts

@@ -107,6 +107,10 @@ class DefaultJSON implements JSON {
   }
 
   async get <T> (cid: CID, options: Partial<GetOptions> = {}): Promise<T> {
+    if (cid.code !== jsonCodec.code) {
+      throw new TypeError('The passed CID had an incorrect codec, it may correspond to a non-JSON block')
+    }
+
     const buf = await this.components.blockstore.get(cid, options)
 
     return jsonCodec.decode(buf)

packages/json/test/get.spec.ts

@@ -2,10 +2,10 @@
 
 import { expect } from 'aegir/chai'
 import { MemoryBlockstore } from 'blockstore-core'
+import { CID } from 'multiformats/cid'
 import { identity } from 'multiformats/hashes/identity'
 import { json, type JSON } from '../src/index.js'
 import type { Blockstore } from 'interface-blockstore'
-import type { CID } from 'multiformats/cid'
 
 describe('get', () => {
   let blockstore: Blockstore
@@ -39,4 +39,10 @@ describe('get', () => {
 
     await expect(j.get(cid)).to.eventually.deep.equal(input)
   })
+
+  it('rejects if CID codec is not equal to JSON codec', async () => {
+    const rawCID = CID.createV1(0x55, cid.multihash)
+    await expect(j.get(rawCID)).to.eventually.be.rejected
+      .with.property('message', 'The passed CID had an incorrect codec, it may correspond to a non-JSON block')
+  })
 })