Session key decryption failed because of Message.fromBinary() instead of Message.read()

[drzraf]

import openpgp from 'openpgp';

const privkey = `-----BEGIN PGP PRIVATE KEY BLOCK-----

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=7vmo
-----END PGP PRIVATE KEY BLOCK-----`,
      pubkey = `-----BEGIN PGP PUBLIC KEY BLOCK-----

mQENBGDtxQUBCADOlWqUON79hoQHMP53dGpY/+CrQNBLWXLCmINDF9HYFimp5WMp
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=wPR/
-----END PGP PUBLIC KEY BLOCK-----`;

var origin = 'abcd',
    cleartext = (new TextEncoder()).encode(origin),
    cleartext_message = openpgp.message.fromBinary(cleartext),
    { keys: [publicKey] } = await openpgp.key.readArmored(pubkey),
    { keys: [privateKey] } = await openpgp.key.readArmored(privkey);

async function as_armored() {
    const {data: encrypted } = await openpgp.encrypt({message: cleartext_message, publicKeys: publicKey, armor: true});
    return await openpgp.message.readArmored(encrypted);
}

async function as_bin() {
    var encrypted = await openpgp.encrypt({message: cleartext_message, publicKeys: publicKey, armor: false});
    encrypted = encrypted.message.packets.write();
    // WRONG! openpgp.message.read(encrypted) must be used here !
    return await openpgp.message.fromBinary(encrypted);
}

// works
// var { data: decrypted } = await openpgp.decrypt({message: await as_armored(), privateKeys: privateKey});
// does not work
var { data: decrypted } = await openpgp.decrypt({message: await as_bin(), privateKeys: privateKey});

console.assert(decrypted == origin);

With the above sample, we get an error Error decrypting message: Session key decryption failed.
This is terribly hard to debug as one could expect this to come from a variety of problems related to the private key itself (non-encrypting key) or the public key. But no way to suspect the message to have been wrongly read. Moreover, using fromBinary as a Message counterpart works and seems plausible and logical.

I know it's 4.10.10 and v5 may have an improved API, but for v4 it's definitely a source of confusion.

[larabr]

Hi @drzraf , the v5 API has been changed to avoid this kind of confusion, by introducing the createMessage and readMessage functions. We are not planning to make changes to v4, since v5 is going to be released soon.