feat: add $width variable for preview commands by pablospe · Pull Request #452 · idursun/jjui

pablospe · 2026-01-03T21:58:10Z

Summary

Add a new $width placeholder variable that exposes the actual view width (in columns) to preview commands
Enables tools like delta to use --side-by-side with the correct width
Width updates dynamically when the preview pane is resized

Motivation

When using delta with --side-by-side in preview commands, there's no way to pass the correct width because jjui pipes command output to an internal buffer (no TTY). This is similar to Discussion #163.

Similar to how fzf exposes $FZF_PREVIEW_COLUMNS, this adds a $width variable.

Example usage

[preview]
revision_command = ["util", "exec", "--", "bash", "-c",
  """jj show --color always --git -r $change_id | delta --side-by-side --width $width"""]

Add a new placeholder variable $width that exposes the actual view width (in columns) to preview commands. This enables tools like delta to use --side-by-side with the correct width. Similar to how fzf exposes $FZF_PREVIEW_COLUMNS, this allows users to configure preview commands that adapt to the view size: ```toml [preview] revision_command = ["util", "exec", "--", "bash", "-c", """jj show --color always --git -r $change_id | delta --side-by-side --width $width"""] ``` The width updates dynamically when the preview pane is resized.

idursun · 2026-01-04T00:21:56Z

Hey thanks,

I’d suggest renaming the placeholder to $preview_width for specificity as it is only populated by the preview.

Also, go fmt is needed.

pablospe · 2026-01-04T19:25:01Z

I’d suggest renaming the placeholder to $preview_width for specificity as it is only populated by the preview.

The initial implementation used $preview_width, but I renamed it to $width because the upcoming feature/configurable-diff-command branch (PR #453) will reuse this placeholder in diff commands as well. A generic $width avoids the situation of having $preview_width in non-preview contexts. But I can change it if you prefer, let me know.

Also, go fmt is needed.

done, thanks!

… is only populated by the preview

- Rename WidthPlaceholder to PreviewWidthPlaceholder - Change placeholder value from $width to $preview_width - Rename local variable back to previewWidth for consistency

pablospe · 2026-01-06T08:40:26Z

I’d suggest renaming the placeholder to $preview_width for specificity as it is only populated by the preview.

done! This PR is ready, let me know otherwise.

idursun

Thanks!

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [idursun/jjui](https://github.com/idursun/jjui) | patch | `v0.9.8` → `v0.9.9` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>idursun/jjui (idursun/jjui)</summary> ### [`v0.9.9`](https://github.com/idursun/jjui/releases/tag/v0.9.9) [Compare Source](idursun/jjui@v0.9.8...v0.9.9) ### Release Notes Another release with small improvements and bug fixes. Thanks to all contributors! #### 🎉 New Features ##### Custom Commands & Lua API Enhancements - **Custom Commands with Sequence Keys** ([#420](idursun/jjui#420)) - Added `key_sequence` property allowing custom commands to be invoked with multiple key presses in sequence - Added `desc` property for command descriptions - Introduced sequence overlay UI showing available key sequences when first key is pressed - Example: `key_sequence = ["w", "b", "l"]` - **Lua API: Choose Method and UI** ([#427](idursun/jjui#427)) ([#442](idursun/jjui#442)) - New `choose()` function for interactive selection prompts in Lua scripts - New `input()` function to prompt users for text input with customizable title and prompt - New `split_lines()` function for text processing - **Lua API: Await on Operation Results** ([#422](idursun/jjui#422)) - `start_inline_describe()` now returns boolean indicating if operation was applied or cancelled - Enables conditional command execution based on user actions - Fixes [#310](idursun/jjui#310) - **Lua API: Interactive Commands** ([commit 8b257263](idursun/jjui@8b257263)) - Added `jj_interactive` Lua function for interactive jj command execution ##### Navigation & UI Improvements - **Ace Jump for Operations** ([#445](idursun/jjui#445)) - Pressing 'f' in set\_parents/duplicate/rebase/squash modes now triggers ace jump - After jump completes, returns to the original operation mode instead of normal mode - Closes [#394](idursun/jjui#394) - **Preview Width Variable** ([#452](idursun/jjui#452)) - Added `$preview_width` placeholder variable for preview commands - Exposes actual view width (in columns) to enable tools like delta to use `--side-by-side` correctly - Width updates dynamically when preview pane is resized - Similar to fzf's `$FZF_PREVIEW_COLUMNS` - **Configurable Flash Message Display Time** ([#456](idursun/jjui#456)) - New config key: `ui.flash_message_display_seconds` (default: 4) - Special value `0` means messages display until manually dismissed - Fixes [#455](idursun/jjui#455) - **Page Up/Down Key Configuration** ([#437](idursun/jjui#437)) - ScrollUp/Down keys now registered in config instead of hardcoded - Keys exposed to configuration for customization - Fixes [#360](idursun/jjui#360) ##### SSH & Authentication - **SSH Askpass Support** ([#423](idursun/jjui#423)) - New `[ssh] hijack_askpass` setting to prompt for SSH passphrases/PINs within jjui - Works on Linux and macOS - Properly handles prompt overriding and cancellation - Fixes [#100](idursun/jjui#100) #### 🐛 Bug Fixes - **Exec Command History** ([#458](idursun/jjui#458)) - Fixed issue where selected command history wasn't applied in exec mode - Input value now properly updated when selecting from fuzzy/regex suggestions - Selected commands correctly saved to history - **Menu Pagination Display** ([#446](idursun/jjui#446)) - Fixed incorrect `%d/%d` pagination display - Height now calculated before pagination render - Added tab/shift+tab to short help menu - Fixes [#444](idursun/jjui#444) - **Flash Message Width** ([#432](idursun/jjui#432)) - Added maxWidth (50% of screen) to flash message rendering - Messages now properly line-wrap instead of extending beyond window width - **Operation Log Refresh** ([#431](idursun/jjui#431)) - Operation log now returns Refresh and SelectionChanged messages upon closing - Fixes [#430](idursun/jjui#430) - **Custom Commands List Sorting** ([commit 3fa9783a](idursun/jjui@3fa9783a)) - Fixed custom commands list to use stable sort - Fixes [#424](idursun/jjui#424) - **JJ Error Pass-through** ([#421](idursun/jjui#421)) - jjui now properly passes through stderr from jj commands - Error messages are more informative and show actual jj errors - **Navigation Message Display** ([commit 94a4a874](idursun/jjui@94a4a874)) - Navigation messages now only shown for paged scrolls #### What's Changed - main: pass through jj error by [@baggiiiie](https://github.com/baggiiiie) in [#421](idursun/jjui#421) - feat(lua): add ability to await on operation results (cancelled/applied) by [@idursun](https://github.com/idursun) in [#422](idursun/jjui#422) - oplog: return Refresh and SelectionChanged upon oplog closing by [@baggiiiie](https://github.com/baggiiiie) in [#431](idursun/jjui#431) - feat(nix): add comprehensive nix flake by [@doprz](https://github.com/doprz) in [#426](idursun/jjui#426) - Add option to hijack SSH Askpass to prompt for passphrase/pin by [@oliverpool](https://github.com/oliverpool) in [#423](idursun/jjui#423) - feat(lua): add choose method and ui by [@idursun](https://github.com/idursun) in [#427](idursun/jjui#427) - flash: add maxWidth to flash msg rendering by [@baggiiiie](https://github.com/baggiiiie) in [#432](idursun/jjui#432) - keys: add pageup/down to keys config by [@baggiiiie](https://github.com/baggiiiie) in [#437](idursun/jjui#437) - chore(github): Add Adda0 as an automatic reviewer for Nix-related changes by [@Adda0](https://github.com/Adda0) in [#440](idursun/jjui#440) - feat: add .editorconfig by [@doprz](https://github.com/doprz) in [#434](idursun/jjui#434) - Add input and log to custom\_commands API by [@ArnaudBger](https://github.com/ArnaudBger) in [#442](idursun/jjui#442) - oplog,list: refactor scrolling with Scrollable/StreamableList interface by [@baggiiiie](https://github.com/baggiiiie) in [#429](idursun/jjui#429) - menu: calculate height before pagination render by [@baggiiiie](https://github.com/baggiiiie) in [#446](idursun/jjui#446) - operations: enable ace jump for set\_parents/duplicate/rebase/squash by [@baggiiiie](https://github.com/baggiiiie) in [#445](idursun/jjui#445) - feat: make flash message display time configurable by [@living180](https://github.com/living180) in [#456](idursun/jjui#456) - feat: add $width variable for preview commands by [@pablospe](https://github.com/pablospe) in [#452](idursun/jjui#452) - status: fix exec command history not applied by [@baggiiiie](https://github.com/baggiiiie) in [#458](idursun/jjui#458) #### New Contributors - [@doprz](https://github.com/doprz) made their first contribution in [#426](idursun/jjui#426) - [@oliverpool](https://github.com/oliverpool) made their first contribution in [#423](idursun/jjui#423) - [@living180](https://github.com/living180) made their first contribution in [#456](idursun/jjui#456) - [@pablospe](https://github.com/pablospe) made their first contribution in [#452](idursun/jjui#452) **Full Changelog**: <idursun/jjui@v0.9.8...v0.9.9> </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Enabled. ♻ **Rebasing**: Whenever MR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this MR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this MR, check this box --- This MR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).

pablospe added 2 commits January 3, 2026 22:47

refactor: rename previewWidth to width for consistency

83ad80c

pablospe requested a review from idursun as a code owner January 3, 2026 21:58

pablospe mentioned this pull request Jan 3, 2026

feat: add configurable diff command with $width and interactive support #453

Closed

style: run go fmt

7f55485

pablospe added 2 commits January 6, 2026 09:32

fix: renaming the placeholder to $preview_width for specificity as it…

5049dd5

… is only populated by the preview

fix: rename placeholder to $preview_width for specificity

b7aab11

- Rename WidthPlaceholder to PreviewWidthPlaceholder - Change placeholder value from $width to $preview_width - Rename local variable back to previewWidth for consistency

idursun approved these changes Jan 7, 2026

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idursun merged commit 036eb76 into idursun:main Jan 7, 2026
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BrewTestBot mentioned this pull request Jan 9, 2026

jjui 0.9.9 Homebrew/homebrew-core#261935

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This was referenced Mar 19, 2026

Preview does not refresh when preview pane is resized #607

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Set preview subprocess size via env #608

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feat: add $width variable for preview commands#452

feat: add $width variable for preview commands#452
idursun merged 5 commits intoidursun:mainfrom
pablospe:feature/preview-width-variable

pablospe commented Jan 3, 2026

Uh oh!

idursun commented Jan 4, 2026

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pablospe commented Jan 4, 2026

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pablospe commented Jan 3, 2026

Summary

Motivation

Example usage

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idursun commented Jan 4, 2026

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pablospe commented Jan 4, 2026

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pablospe commented Jan 6, 2026

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