zulip/zulip-terminal

IndexError on starting (focus index vs message id)

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#1,226 opened on May 16, 2022

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bug: crashfurther discussion requiredhelp wanted

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Description

This was discussed in #zulip-terminal > IndexError while starting., and has been reported by:

  • Aryan Shridhar
  • @Dishti-Oberai
  • @rht

This appears to be distinct from #326.

ZT is reported to crash before the UI loads.

The traceback ends with

IndexError: focus index is out of range: 1330877

(where the last number varies)

The bug currently occurs due to views.py line 119, on the assumption that:

  • the model provides a current focused message id
  • the focused message is set to the id
  • the initializer for MessageView sets the listbox focus to that id...
  • ...which is likely out of range, given ~30 messages in list, and message ids potentially being huge!

A temporary workaround is to remove that statement, but a fuller solution should likely consider how we handle/retain focus between narrows.

Contributor guide

Research direction
Investigate how the model determines the focused message ID and ensure it is mapped to a valid listbox index before setting focus. Consider implementing a lookup from message ID to index in the message list.
Tech stack
python
Domain
cli
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PythonGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75