fix(session): use parent link for loop exit

[BestSithInEU]

Summary

• Use the assistant message parent link to determine whether the latest assistant response belongs to the latest user message.
• Avoid relying on lexicographic/time-sortable message ID ordering for the session loop exit condition.

Motivation

The current loop exit guard compares message IDs:

lastUser.id<lastAssistant.id

That can be fragile when user and assistant messages are created in different contexts or clocks, and can prevent the prompt loop from exiting even after a final assistant response.

Assistant messages are created with:

parentID: lastUser.id

So checking that relationship is the direct condition.

This is related to reports of repeated session.prompt step=N loop after tool/assistant completion.

Validation

• Built a local single-platform binary with this patch:
  bun run build -- --single --skip-install --skip-embed-web-ui
• Build smoke test passed: opencode --version
• bun turbo typecheck passed during branch push hook
• Local patched session exited to idle after previously looping: observed session.prompt ... exiting loop and session.idle publishing

[github-actions]

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[github-actions]

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potentially Related PRs Found:

1. fix: robust subagent completion propagation #13321 - fix: robust subagent completion propagation

   • Related to session loop and completion handling

2. fix(session): exclude orphaned interrupted tools from run-loop continuation #26178 - fix(session): exclude orphaned interrupted tools from run-loop continuation

   • Directly addresses session loop continuation logic, similar domain

3. fix(opencode): prevent same-parent assistant siblings during concurrent prompts (#28202) #28488 - fix(opencode): prevent same-parent assistant siblings during concurrent prompts

   • Addresses parent link relationships between assistant messages

The search results show related PRs that touch on session loop exit conditions and parent-child message relationships, but these appear to be older fixes addressing different aspects of the same system. PR #29032 (your current PR) is a distinct fix targeting the specific issue of using parent links for loop exit conditions instead of relying on message ID ordering.

[BestSithInEU]

Closing to recreate with the repository pull request template.