TypeError: undefined is not an object (evaluating 'toSummarize.at(-1).info')

[sahilchouksey]

Description

A TypeError: undefined is not an object (evaluating 'toSummarize.at(-1).info') occurs during session summarization when attempting to create issue content.

Steps to Reproduce

1. Trigger session summarization in scenarios where there are 0 or 1 messages after the last summary message.
2. The error occurs at line 1826 in packages/opencode/src/session/index.ts when accessing toSummarize.at(-1).info.time.created.

Expected Behavior

Session summarization should handle cases with no messages to summarize gracefully without throwing an error.

Actual Behavior

The application throws a TypeError because toSummarize is an empty array, and at(-1) returns undefined.

Root Cause

The summarize function assumes toSummarize (a slice of messages) is non-empty, but it can be empty when msgs.length - start is 0 or 1, leading to an empty slice.

Environment

• Platform: Linux
• Opencode version: 0.7.3

Additional Context

This error prevents proper session compaction and interrupts user workflows

[github-actions]

This issue might be a duplicate or related to existing issues. Please check:

• compact causes llm to forget convo #2234: Issues with compact functionality causing conversation context problems
• Edge-case in tool calls for auto-compacting #970: Edge-case in tool calls for auto-compacting, which mentions context/compaction issues
• bug: /compact is not interruptable #606: Problems with compact command interruption (closed, but related to compaction functionality)

The error you're experiencing seems to be in the summarization logic during session compaction. While not exact duplicates, these issues all relate to problems with the compaction/summarization system.

Feel free to ignore if none of these address your specific case.

[vldF]

I have this too

[thdxr]

should be fixed now