Temporary error upon loading the card

[afarago]

Checklist:

• I updated to the latest version available
• I cleared the cache of my browser

Release with the issue:
5.3.0

Last working release (if known):

Browser and Operating System:
Version 119.0.6045.160 (Official Build) (64-bit)
Windows 11

Description of problem:
Initial loading of the page shows an error, that disappears in <1 sec, still is quite disturbing.

This comes upw even with the simplest layout of the card.

Javascript errors shown in the web inspector (if applicable):
none

Additional information:
example config tested:

type: custom:hourly-weather
entity: weather.home

[decompil3d]

Interesting, I wonder if this is a result of the recent change to use a web service call to get forecasts from HA. Perhaps we can hold off on showing errors if the web service call hasn't completed yet. If someone has time to look at this I can look at a PR. Otherwise, I'll get to this when I can.

[evilmouse69]

I also got the same error come up on my little wall panel

[afarago]

So in the past days I was able to debug the problem, and get the root cause.

• (I have a quite big dashboard with multiple different cards, using Meteorologisk institutt (Met.no))
• initially we start the subscription with subscribeToForecastEvents
• upon loading card starts rendering renderCore
• this calls const forecast = this.getForecast();
• as there is no answer yet from the subscription ( this.forecastEvent?.forecast is equals null in private getForecast() that returns the default daily granularity from the this.hass?.states[this.config.entity]?.attributes.forecast (6 items with daily granularity))
• yields to error (this._showError(this.localize('errors.too_many_segments_requested')))
• shortly HA kicks in for the subscription and subscribeMessage callback returns with the hourly distribution (24 entries in the array)
• card re-renders with correct content.

I have an initial suggestion, please feel to review the PR and comment/modify.