read[Private]Key: support parsing key blocks (return first parsable key)

Previously, `readKey` and `readPrivateKey` would throw when given a block
of keys as input.
With this change, the first parsable key is returned by both functions:
the behaviour is equivalent to calling `readKeys` (resp. `readPrivateKeys`)
and taking the first array entry.

src/key/factory.js

@@ -340,7 +340,12 @@ export async function readKey({ armoredKey, binaryKey, config, ...rest }) {
     input = binaryKey;
   }
   const packetlist = await PacketList.fromBinary(input, allowedKeyPackets, config);
-  return createKey(packetlist);
+  const keyIndex = packetlist.indexOfTag(enums.packet.publicKey, enums.packet.secretKey);
+  if (keyIndex.length === 0) {
+    throw new Error('No key packet found');
+  }
+  const firstKeyPacketList = packetlist.slice(keyIndex[0], keyIndex[1]);
+  return createKey(firstKeyPacketList);
 }
 
 /**
@@ -377,7 +382,15 @@ export async function readPrivateKey({ armoredKey, binaryKey, config, ...rest })
     input = binaryKey;
   }
   const packetlist = await PacketList.fromBinary(input, allowedKeyPackets, config);
-  return new PrivateKey(packetlist);
+  const keyIndex = packetlist.indexOfTag(enums.packet.publicKey, enums.packet.secretKey);
+  for (let i = 0; i < keyIndex.length; i++) {
+    if (packetlist[keyIndex[i]].constructor.tag === enums.packet.publicKey) {
+      continue;
+    }
+    const firstPrivateKeyList = packetlist.slice(keyIndex[i], keyIndex[i + 1]);
+    return new PrivateKey(firstPrivateKeyList);
+  }
+  throw new Error('No secret key packet found');
 }
 
 /**

test/general/openpgp.js

@@ -990,6 +990,62 @@ export default () => describe('OpenPGP.js public api tests', function() {
       });
     });
 
+    it('readPrivateKey and readPrivateKeys should have consistent results', async function() {
+      const privateAndPublicKeyBlock = `-----BEGIN PGP PRIVATE KEY BLOCK-----
+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+-----END PGP PRIVATE KEY BLOCK-----`;
+      // readPrivateKey should read the first private key encountered in a key block
+      const key = await openpgp.readPrivateKey({ armoredKey: privateAndPublicKeyBlock });
+      const privateKeys = await openpgp.readPrivateKeys({ armoredKeys: privateAndPublicKeyBlock });
+      expect(privateKeys.length).to.equal(1);
+      expect(key.isPrivate()).to.be.true;
+      expect(privateKeys[0].isPrivate()).to.be.true;
+      expect(key.isDecrypted()).to.be.true;
+      expect(privateKeys[0].isDecrypted()).to.be.true;
+      expect(key.getKeyID().equals(privateKeys[0].getKeyID())).to.be.true;
+    });
+
+    it('readKey and readKeys should have consistent results', async function() {
+      const publicAndPrivateKeyBlock = `-----BEGIN PGP PRIVATE KEY BLOCK-----
+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+-----END PGP PRIVATE KEY BLOCK-----`;
+      // readKey should read the first key encountered in a key block
+      const key = await openpgp.readKey({ armoredKey: publicAndPrivateKeyBlock });
+      const keys = await openpgp.readKeys({ armoredKeys: publicAndPrivateKeyBlock });
+      expect(keys.length).to.equal(2);
+      expect(key.isPrivate()).to.be.false;
+      expect(keys[0].isPrivate()).to.be.false;
+      expect(keys[1].isPrivate()).to.be.true;
+    });
+
     it('readPrivateKey should throw on armored public key', async function() {
       await expect(openpgp.readPrivateKey({ armoredKey: pub_key })).to.be.rejectedWith(/Armored text not of type private key/);
     });