Truffle console: Assignments involving an await return undefined

Issue

In Truffle Console, if you enter an assignment expression, and the right-hand-side involves an await, the return value incorrectly shows as undefined.

Both the assignment and the await seems to be necessary. For instance, both x = 3 and await 3 correctly show 3; however, x = await 3 shows undefined.

This also happens in more complicated assignments involving await, such as x = (await 3) + 1. Of course, note that more complicated expressions like this may not work at all, as per #1546! Indeed I assume this issue is probably related to #1546 somehow… (but maybe it’s easier to fix? IDK).

Steps to Reproduce

Open truffle console in a Truffle project.

Enter:

x = await 3

x = (await 3) + 1

Expected Behavior

The return values should be 3 and 4, respectively.

Actual Results

The return values are both undefined.

Environment

• Operating System: Release Linux Mint 20 Ulyana 64-bit
• Ethereum client: Ganache CLI v6.10.1 (ganache-core: 2.11.2)
• Truffle version (truffle version): 5.1.41
• node version (node --version): v10.15.3
• npm version (npm --version): 6.14.5

[mdg215199]

Thank you for the video, I had to watch it a second time, as the first, I was skipping through instead of fully watching the last part of it. Absolutely solved the issue I was having.

[haltman-at]

@cds-amal, I think that statement needs some elaboration!

What Amal actually did is not to somehow pass the equivalent of the --experimental-repl-await flag to the repl library, but rather to pass the actual --experimental-repl-await flag to the instance of Node that’s running Truffle! That is to say, we could add it to the shebang line in @truffle/core!

It’s a little unclear whether this suffices for our purposes, but it just might… after all, it’s not like we create a REPL from any other package!