[Pasted ~N lines] is partially submitted when prompt contains CJK or other multi-width characters

[AbigailJixiangyuyu]

Description

This is a TUI-specific issue.

When the prompt contains CJK or other multi-width characters before a pasted preview token like [Pasted ~N lines], submitting the prompt may incorrectly include part of the preview text in the final prompt instead of fully replacing it with the pasted content.

This does not seem to be a general encoding issue. The root cause appears to be that the replacement logic mixes terminal visual-width offsets with JavaScript string indices. For ASCII input this works, but for Chinese, Japanese, Korean, emoji, and other multi-width characters, the replacement range becomes misaligned.

Plugins

No Plugins

OpenCode version

1.2.24

Steps to reproduce

1. Type Chinese text or any CJK in the prompt input.
2. Paste a multi-line block of text so that OpenCode inserts a preview like [Pasted ~N lines].
3. Submit the prompt.
4. Observe that part of the [Pasted ~N lines] preview text is included in the final submitted prompt instead of being fully replaced by the pasted content.

Screenshot and/or share link

No response

Operating System

Windows11

Terminal

Powershell

[github-actions]

This issue might be a duplicate of an existing issue. Please check:

• Paste preview indicator "[Pasted ~N lines]" incorrectly included in submitted input #11143: Same symptom where [Pasted ~N lines] preview text is incorrectly included in the submitted prompt. Your issue provides additional context that CJK/multi-width characters trigger a specific misalignment in the replacement logic, which may or may not be the same underlying bug.

If this is a distinct root cause (visual-width vs. string-index mismatch specific to multi-width characters), feel free to clarify that so maintainers can keep both open if needed.

[AbigailJixiangyuyu]

This issue might be a duplicate of an existing issue. Please check:

• Paste preview indicator "[Pasted ~N lines]" incorrectly included in submitted input #11143: Same symptom where [Pasted ~N lines] preview text is incorrectly included in the submitted prompt. Your issue provides additional context that CJK/multi-width characters trigger a specific misalignment in the replacement logic, which may or may not be the same underlying bug.

If this is a distinct root cause (visual-width vs. string-index mismatch specific to multi-width characters), feel free to clarify that so maintainers can keep both open if needed.

No, they’re not the same issue.