Block difficulty is always '0' (zero)

Expected Behavior

Hardhat (on the left) has difficulty and totalDifficulty values set

Current Behavior

Ganache (on the right) has both difficulty and totalDifficulty values equal to zero.

Possible Solution

Both projects use ethereumjs-vm version v4.2.0.

I assume the difference happens during block creation (as far as I remember Hardhat set difficulty based on the latest block):

https://github.com/nomiclabs/hardhat/blob/6c3cdb7445c3b2960ed6bfce50d09bc11338479e/packages/hardhat-core/src/internal/hardhat-network/provider/node.ts#L1040

Ganache doesn’t seem to have any difficulty-related header assignment:

https://github.com/trufflesuite/ganache-core/blob/1177fe8a2711066a1b082b15d22585158001e80d/lib/blockchain_double.js#L600

P.S. Btw, also https://github.com/ethereumjs/ethereumjs-vm/pull/929 was merged 5 days ago - introducing a new way of setting a difficulty in ethereumjs-vm (but Hardhat was setting difficulty before this release).

[eggplantzzz]

https://github.com/trufflesuite/ganache-core/pull/771 addresses this issue.

[davidmurdoch]

Ah, thanks for the use-case example.

Also, looks like there are two bugs in forking:

1. On blocks fetched from the original chain we are setting difficulty to totalDifficulty.
2. Even though we’ve intended for difficulty to be 0, we don’t keep the totalDifficulty around, as we should.

As for your use-case example, i’ll talk to the team internally and see what we can come up with!