Insert Text and Trigger Completion

Oct 13, 2025 by wbrum.org 79 views

Introduction

Vim is a powerful text editor that offers a wide range of features and customization options. One of its key features is the completion system, which allows users to complete words and phrases as they type. However, there are certain situations where the completion system may not behave as expected. In this article, we will explore a specific issue where text is pre-inserted into the buffer when the preinsert option is not included in the completeopt setting.

Steps to Reproduce

To reproduce this issue, follow these steps:

Start Vim in Clean Mode: Run the command vim --clean to start Vim in clean mode. This will ensure that we have a clean and empty buffer to work with.
Set Completeopt: Run the command :set completeopt=menu,menuone,noinsert,noselect to set the completeopt option. This will enable the completion menu and disable the insert option.
Highlight ComplMatchIns: Run the command :hi ComplMatchIns ctermfg=red guifg=red to highlight the ComplMatchIns group. This will make it easier to see the text that is inserted into the buffer.
Write Sample Text: Write the following three lines of text:
```
house
horse
hollow
```
Insert Text and Trigger Completion: On a new line, insert the text ho and then press <C-N> to trigger completion mode. The completion menu should contain the options "house", "horse", and "hollow".

Expected Behaviour

When the preinsert option is not included in the completeopt setting, we would expect the completion menu to display the options without inserting any text into the buffer as we select each option. However, in this case, the text for each option is inserted into the buffer in red, even though preinsert is not part of 'completeopt'.

Version of Vim

The version of Vim used to reproduce this issue is 9.1.1150.

Environment

The environment used to reproduce this issue is:

Operating system: Ubuntu 24.04
$TERM: xterm-ghostty
Shell: fish 4.0

Logs and Stack Traces

There are no logs or stack traces to report in this case.

Analysis

The issue appears to be related to the way that Vim handles the completeopt setting. When the preinsert option is not included in the completeopt setting, Vim seems to be inserting the text for each completion option into the buffer, even though it should not be doing so. This is likely due to a bug or a misconfiguration in the completion system.

Workaround

One possible workaround for this issue is to include the preinsert option in the completeopt setting. This can be done by running the command :set completeopt=menu,menuone,preinsert,noselect. This will ensure that the text for each completion option is not inserted into the buffer, as expected.

Conclusion

In conclusion, the issue where text is pre-inserted into the buffer when the preinsert option is not included in the completeopt setting is a bug or a misconfiguration in the completion system of Vim. While there is a workaround available, it would be better to fix the underlying issue to ensure that the completion system behaves as expected.

Future Development

To fix this issue, the Vim developers should investigate the completion system and determine why the preinsert option is not being respected when it is not included in the completeopt setting. This may involve modifying the code that handles the completeopt setting or adding additional checks to ensure that the preinsert option is respected.

Recommendations

Based on this analysis, we recommend that Vim users include the preinsert option in the completeopt setting to avoid this issue. We also recommend that the Vim developers investigate and fix the underlying issue to ensure that the completion system behaves as expected.

Additional Information

Introduction

In our previous article, we explored a specific issue where text is pre-inserted into the buffer when the preinsert option is not included in the completeopt setting in Vim. In this article, we will answer some frequently asked questions (FAQs) related to this issue.

Q: What is the `completeopt` setting in Vim?

A: The completeopt setting in Vim is used to configure the completion system. It determines how the completion menu is displayed and how the text is inserted into the buffer.

Q: What is the `preinsert` option in the `completeopt` setting?

A: The preinsert option in the completeopt setting is used to determine whether the text for each completion option is inserted into the buffer before the user selects it.

Q: Why is the `preinsert` option not being respected when it is not included in the `completeopt` setting?

A: The reason for this issue is not yet clear, but it is likely due to a bug or a misconfiguration in the completion system.

Q: How can I fix this issue?

A: One possible workaround for this issue is to include the preinsert option in the completeopt setting. This can be done by running the command :set completeopt=menu,menuone,preinsert,noselect.

Q: What are the consequences of not including the `preinsert` option in the `completeopt` setting?

A: If the preinsert option is not included in the completeopt setting, the text for each completion option will be inserted into the buffer before the user selects it. This can lead to unexpected behavior and errors.

Q: How can I prevent the text from being inserted into the buffer?

A: To prevent the text from being inserted into the buffer, you can include the preinsert option in the completeopt setting.

Q: Is this issue specific to Vim 9.1.1150?

A: The issue is not specific to Vim 9.1.1150, but it may be related to the specific version of Vim being used.

Q: Can I report this issue to the Vim developers?

A: Yes, you can report this issue to the Vim developers by submitting a bug report on the Vim bug tracker.

Q: How can I get help with this issue?

A: You can get help with this issue by asking in the Vim community or on the Vim mailing list.

Conclusion

Additional Information

For more information on the completeopt setting and the completion system in Vim, please refer to the Vim documentation. Additionally, if you have any questions or concerns about this issue, please feel free to ask in the Vim community or on the Vim mailing list.