Bug: Spikes in price graph of investment accounts

[cwognum]

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Bug description

I manually created an investment account. I first specified the Balance, and subsequently specified my single holding for that account with a Transaction. The value of the account generally updates as expected, but on rare occasions jumps back to the value it had at the time of the transaction.

I've only been using Maybe for ~2 weeks, so I don't have much to go on here.

However, I was initially under the impression this happens because there is no price data for the holding on such days (e.g. the weekend, as markets are closed). Perhaps Maybe then falls back to the last specified price at the time of the transaction. This would explain the first two-day spike (May 10 and 11), as well as the second-to-last spike (May 17) in the screenshot below.

However, that would not explain the very last spike (May 20) and also wouldn't explain why there is no spike on May 18 (a Sunday).

Steps to reproduce

I don't have a minimal example, but this is what I did:

1. Click on New Account.
2. Click on Investment.
3. Click on Enter Account Balance and manually specified the balance.
4. Go the page of the newly created account.
5. Click on New.
6. Click on New transaction.
7. Fill out the requested details.
8. Observe!

Expected behavior

I marked the expected behavior with a dark red, dashed line in the screenshot below. I would not expect any spikes.

Screenshots and/or recordings

[zachgoll]

@cwognum thanks for the detailed visual here. That definitely helps debug things.

Your assumption is correct, we first lookup prices from our market data provider. If we can't find a price there, we fall back to the last known trade price.

I think your visual is also correct that we should NOT be falling back to prices like this, but rather something like:

1. If provider price, use it
2. If no provider price
   a) Is there a holding value yesterday? If so, carry its value forward
   b) No holding value? Use last trade price as an absolute last resort fallback

I'm working on some of this logic in #2267 and will be sure to incorporate this.

[cwognum]

Awesome, thanks @zachgoll !

The proposed logic makes perfect sense.

[cwognum]

Hey @zachgoll , don't mean to sound impatient, but I saw that #2267 got merged.

I'm currently still seeing the same spikes in my graph. Is that expected?

[zachgoll]

@cwognum yep, that's expected. #2267 had a ton of changes, so I decided to tackle this issue in a follow-up.

[cwognum]

As noted in the original issue, I'm also seeing some spikes on days for which the market value normally should be available. I can't quite put my finger on why this happens, but I have half a suspicion.

In the last few days I noticed that it tends to happen when I sign in during the evenings. Two thoughts:

• Could it be because I look up the price after the market has closed? I'm not seeing this issue in the morning though, prior to the marketing opening.
• Or could it be a timezone-related issue? I'm based in the Eastern Time Zone (EST) and when I login during the evening, UTC is already on the next day. Perhaps Maybe requests the market value for the next day, rather than the current one?

Either way, the graph shows the spike for the next day and the price doesn't get updated when I log in again the following day.

Realize this is not very actionable yet, but wanted to share it already. Will investigate further!