[HOLD for payment 2024-04-15] [$500] One character jumps after cursor when typing fast

[m-natarajan]

If you haven’t already, check out our contributing guidelines for onboarding and email contributors@expensify.com to request to join our Slack channel!

---

Version Number: 1.4.58-4
Reproducible in staging?: y
Reproducible in production?: y
If this was caught during regression testing, add the test name, ID and link from TestRail:
Email or phone of affected tester (no customers):
Logs: https://stackoverflow.com/c/expensify/questions/4856
Expensify/Expensify Issue URL:
Issue reported by: @mountiny
Slack conversation: https://expensify.slack.com/archives/C049HHMV9SM/p1711707948520499

Action Performed:

1. Open any chat
2. Type fast in the composer

Expected Result:

All the characters added should be before the cursor

Actual Result:

One character jumps after the cursor.
NOTE: Very hard to reproduce. I had to type 2 lines to reproduce this bug

Workaround:

unknown

Platforms:

Which of our officially supported platforms is this issue occurring on?

• Android: Native
• Android: mWeb Chrome
• iOS: Native
• iOS: mWeb Safari
• MacOS: Chrome / Safari
• MacOS: Desktop

Screenshots/Videos

Add any screenshot/video evidence

Recording.2929.mp4

Screen.Recording.2024-03-29.at.10.22.06.mp4

View all open jobs on GitHub

Upwork Automation - Do Not Edit

• Upwork Job URL: https://www.upwork.com/jobs/~0109e66f48fc7c7130
• Upwork Job ID: 1775928557129052160
• Last Price Increase: 2024-04-04

[melvin-bot]

Triggered auto assignment to @bfitzexpensify (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details.

[ZhenjaHorbach]

Actually, problem related with MarkdownTextInput and with this useEffect

https://github.com/Expensify/react-native-live-markdown/blob/main/src/MarkdownTextInput.web.tsx#L527-L533

When we quickly enter text, desynchronization occurs with the current value from the props and with the current value of the input itself
As a result, we select the previous characters from props

As far as I know, these problems are being fixed by the creators of the component
But I think in order to fix this We can use debounce function to make sure that the values are kept in sync when entering text

[thienlnam]

Added to the tracking issue, going to upgrade this to a high since I can reproduce pretty reliably on Desktop

[aldo-expensify]

I agree with the cause being what @ZhenjaHorbach found here. In my testing, I put a debugger and I can see that contentSelection has the wrong values (36), while it should really have 37 which is the current text length.