# Configuration

These are the config settings available to jj/Jujutsu.

## Config files and TOML

`jj` loads several types of config settings:

- The built-in settings. These cannot be edited. They can be viewed in the
  `cli/src/config/` directory in `jj`'s source repo.

- The user settings. These can be edited with `jj config edit --user`. User
settings are located in [the user config files], which can be found with `jj
config path --user`.

- The repo settings. These can be edited with `jj config edit --repo` and are
located in `.jj/repo/config.toml`.

- The workspace settings. These can be edited with `jj config edit --workspace`
and are located in `.jj/workspace-config.toml` in the workspace root.

- Settings [specified in the command-line](#specifying-config-on-the-command-line).

These are listed in the order they are loaded; the settings from earlier items
in the list are overridden by the settings from later items if they disagree.
Every type of config except for the built-in settings is optional.

You can enable JSON Schema validation in your editor by adding a `#:schema`
reference at the top of your TOML config files. See [JSON Schema
Support] for details.

See the [TOML site] and the [syntax guide] for a detailed description of the
syntax. We cover some of the basics below.

[the user config files]: #user-config-files
[TOML site]: https://toml.io/en/
[syntax guide]: https://toml.io/en/v1.0.0
[JSON Schema Support]: #json-schema-support

The first thing to remember is that the value of a setting (the part to the
right of the `=` sign) should be surrounded in quotes if it's a string.

### Dotted style and headings
In TOML, anything under a heading can be dotted instead. For example,
`user.name = "YOUR NAME"` is equivalent to:

```toml
[user]
name = "YOUR NAME"
```

For future reference, here are a couple of more complicated examples,

```toml
# Dotted style
template-aliases."format_short_id(id)" = "id.shortest(12)"
colors."commit_id prefix".bold = true

# is equivalent to:
[template-aliases]
"format_short_id(id)" = "id.shortest(12)"

[colors]
"commit_id prefix" = { bold = true }
```

The docs below refer to keys in text using dotted notation, but example
blocks will use heading notation to be unambiguous. If you are confident with TOML
then use whichever suits you in your config. If you mix dotted keys and headings,
**you must put the dotted keys before the first heading**.

That's probably enough TOML to keep you out of trouble but the [syntax guide] is
very short if you ever need to check.

## User settings

```toml
[user]
name = "YOUR NAME"
email = "YOUR_EMAIL@example.com"
```

Don't forget to change these to your own details!

## UI settings

### Colorizing output

Possible values are `always`, `never`, `debug` and `auto` (default: `auto`).
`auto` will use color only when writing to a terminal. `debug` will print the
active labels alongside the regular colorized output.

This setting overrides the `NO_COLOR` environment variable (if set).

```toml
[ui]
color = "never" # Turn off color
```

### Custom colors and styles

You can customize the colors used for various elements of the UI. For example:

```toml
[colors]
commit_id = "green"
```

The following colors are available:

* black
* red
* green
* yellow
* blue
* magenta
* cyan
* white
* default

All of them but "default" come in a bright version too, e.g. "bright red". The
"default" color can be used to override a color defined by a parent style
(explained below).

You can also use a 6-digit hex code for more control over the exact color used:

```toml
[colors]
change_id = "#ff1525"
```

`jj` also supports colors from the [ANSI 256-color palette] as `ansi-color-<N>`,
where `<N>` is a number between 0 and 255:

```toml
[colors]
commit_id = "ansi-color-81"
```

[ANSI 256-color palette]: https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit

If you use a string value for a color, as in the examples above, it will be used
for the foreground color. You can also set the background color, reverse colors
(swap foreground and background), or make the text bold, dim, italic, or
underlined. For that, you need to use a table:

```toml
[colors]
commit_id = { fg = "green", bg = "#ff1525", bold = true, underline = true }
change_id = { reverse = true, dim = false, italic = true }
```

The key names are called "labels". The above used `commit_id` as label. You can
also create rules combining multiple labels. The rules work a bit like CSS
selectors. For example, if you want to color commit IDs green in general but
make the commit ID of the working-copy commit also be underlined, you can do
this:

```toml
[colors]
commit_id = "green"
"working_copy commit_id" = { underline = true }
```

Parts of the style that are not overridden - such as the foreground color in the
example above - are inherited from the style of the parent label.

Which elements can be colored is not yet documented, but see
the [default color configuration](https://github.com/jj-vcs/jj/blob/main/cli/src/config/colors.toml)
for some examples of what's possible.

### Default command

When `jj` is run with no explicit subcommand, the value of the
`ui.default-command` setting will be used instead. Possible values are any valid
subcommand name, subcommand alias, or user-defined alias (defaults to `"log"`).

```toml
[ui]
default-command = ["log", "--reversed"]
```

### Default description

The editor content of a commit description can be populated by the
`draft_commit_description` template. `self` is a [`Commit`
object](templates.md#commit-type).

```toml
[templates]
draft_commit_description = '''
concat(
  builtin_draft_commit_description,
  "\nJJ: ignore-rest\n",
  diff.git(),
)
'''
```

You can override only the `default_commit_description` value if you like, e.g.:

```toml
[template-aliases]
default_commit_description = '''
"

Closes #NNNN
"
'''
```

### Duplicate commit description

By default, `jj duplicate` copies the descriptions from the original commits.
You can customize this behavior by specifying the `duplicate_description`
template, which is given a [`Commit` object](templates.md#commit-type) of the
original commit.

```toml
[templates]
duplicate_description = '''
concat(
  description,
  "\n(cherry picked from commit ",
  commit_id,
  ")"
)
'''
```

### Bookmark listing order

By default, `jj bookmark list` displays bookmarks sorted alphabetically by name.
You can customize this sorting behavior by specifying sort keys in your config
file:

```toml
[ui]
bookmark-list-sort-keys = ["name"]
```

The configuration works identically to using the `--sort` option for
`jj bookmark list`. The following sort keys are supported: `name`, `author-name`,
`author-email`, `author-date`, `committer-name`, `committer-email`,
`committer-date`. Suffix the key with `-` to sort in descending order. Multiple
keys can be supplied here, the first key is the most significant.

When the `--sort` option is used with `jj bookmark list`, the configuration
is ignored.

### Commit trailers

You can configure automatic addition of one or more trailers to commit
descriptions using the `commit_trailers` template.

Each line of the template is an individual trailer, usually in `Key: Value`
format.

Trailers defined in this template are deduplicated with the existing
description: if the entire line of a trailer is already present, it will not be
added again. To deduplicate based only on the trailer key, use the
`trailers.contains_key(key)` method within the template.

```toml
[templates]
commit_trailers = '''
format_signed_off_by_trailer(self)
++ if(!trailers.contains_key("Change-Id"), format_gerrit_change_id_trailer(self))'''
```

Some ready-to-use trailer templates are available for frequently used trailers:
* `format_signed_off_by_trailer(commit)` creates a "Signed-off-by" trailer
  using the committer info.
* `format_gerrit_change_id_trailer(commit)` creates a "Change-Id" trailer
  suitable to be used with Gerrit. It is based Jujutsu's change id.

Existing trailers are also accessible via `commit.trailers()`.

### Diff colors and styles

In color-words and git diffs, word-level hunks are rendered with underline. You
can override the default style with the following keys:

```toml
[colors]
# Highlight hunks with background
"diff removed token" = { bg = "#221111", underline = false }
"diff added token" = { bg = "#002200", underline = false }
# Alternatively, swap colors
"diff token" = { reverse = true, underline = false }
```

In color-words diffs, line numbers of context lines are rendered with decreased
intensity to highlight changed lines. You can also decrease intensity of context
contents.

```toml
[colors]
# Dim context line numbers (default)
"diff context line_number" = { dim = true }
# Dim context line numbers and contents (applies to color-words and git diffs)
"diff context" = { dim = true }
```

### Diff format

```toml
[ui]
# Builtin formats: ":color-words" (default), ":git",
#                  ":summary", ":stat", ":types", ":name-only"
# or external command name and arguments (see below)
diff-formatter = ":git"
```

#### Color-words diff options

In color-words diffs, changed words are displayed inline by default. Because
it's difficult to read a diff line with many removed/added words, there's a
threshold to switch to traditional separate-line format. You can also change
the default number of lines of context shown.

* `max-inline-alternation`: Maximum number of removed/added word alternation to
  inline. For example, `<added> ... <added>` sequence has 1 alternation, so the
  line will be inline if `max-inline-alternation >= 1`. `<added> ... <removed>
  ... <added>` sequence has 3 alternation.

  * `0`: disable inlining, making `--color-words` more similar to `--git`
  * `1`: inline removes-only or adds-only lines
  * `2`, `3`, ..: inline up to `2`, `3`, .. alternation
  * `-1`: inline all lines

  The default is `3`.

  **This parameter is experimental.** The definition is subject to change.

* `conflict`: How conflicts are processed and displayed.

   * `"materialize"`: compare materialized contents (default)
   * `"pair"`: compare individual pairs

   **This parameter is experimental.**

* `context`: Number of lines of context to show in the diff. The default is `3`.

```toml
[diff.color-words]
max-inline-alternation = 3
context = 3
```

#### Git diff options

In git diffs you can change the default number of lines of context shown.

* `context`: Number of lines of context to show in the diff. The default is `3`.

```toml
[diff.git]
context = 3
```

### Generating diffs by external command

If `ui.diff-formatter` is not a builtin format, the specified diff command will
be called.

```toml
[ui]
# Use Difftastic by default
diff-formatter = ["difft", "--color=always", "$left", "$right"]
# Use tool named "<name>" (see below)
diff-formatter = "<name>"
```

The external diff tool can also be enabled by `diff --tool <name>` argument.
For the tool named `<name>`, command arguments can be configured as follows.

```toml
[merge-tools.<name>]
# program = "<name>"  # Defaults to the name of the tool if not specified
diff-args = ["--color=always", "$left", "$right"]
```

- `$left` and `$right` are replaced with the paths to the left and right
  directories to diff respectively.

- `$width` is replaced with the number of terminal columns available to the diff
  content.

- If `diff-args` is not specified, `["$left", "$right"]` will be used by default.

- If `diff-args = []`, `jj` will refuse to use this tool for diff formatting.
  This is a way to explicitly state that a certain tool (e.g. `mergiraf`) does
  not work for viewing diffs.

By default `jj` will invoke external tools with a directory containing the left
and right sides.  The `diff-invocation-mode` config can change this to file by file
invocations as follows:

```toml
[ui]
diff-formatter = "vimdiff"

[merge-tools.vimdiff]
diff-invocation-mode = "file-by-file"
```

By default `jj` will display a warning when the command exits with a non-success
error code. The `diff-expected-exit-codes` config can suppress this warning
message for specific exit codes:

```toml
[merge-tools.delta]
diff-expected-exit-codes = [0, 1]
```

### Conflict marker style

You can configure which style of conflict markers to use when materializing
conflicts:

```toml
[ui]
# Shows a single snapshot and one or more diffs to apply to it
conflict-marker-style = "diff"
# Shows a snapshot for each side and base of the conflict
conflict-marker-style = "snapshot"
# Uses Git's "diff3" conflict markers to support tools that depend on it
conflict-marker-style = "git"
```

For more details about these conflict marker styles, see the [conflicts
page](conflicts.md#conflict-markers).

### Set of immutable commits

You can configure the set of immutable commits via
`revset-aliases."immutable_heads()"`. The default set of immutable heads is
`builtin_immutable_heads()`, which in turn is defined as
`present(trunk()) | tags() | untracked_remote_bookmarks()`. For example, to
also consider the `release@origin` bookmark immutable:

```toml
[revset-aliases]
"immutable_heads()" = "builtin_immutable_heads() | release@origin"
```

To prevent rewriting commits authored by other users:

```toml
# The `trunk().. &` bit is an optimization to scan for non-`mine()` commits
# only among commits that are not in `trunk()`.
[revset-aliases]
"immutable_heads()" = "builtin_immutable_heads() | (trunk().. & ~mine())"
```

Ancestors of the configured set are also immutable. The root commit is always
immutable even if the set is empty.

Immutable commits (other than the root commit) can be rewritten using the
`--ignore-immutable` CLI flag.

!!! warning

    Using `--ignore-immutable` will allow you to rewrite any commit in the
    history, and all descendants, without warning. Use this power wisely, and
    remember `jj undo`.

### Behavior of prev and next commands

If you prefer using an "edit-based" workflow, rather than squashing
modifications into parent changes, you may find yourself using the `prev` and
`next` commands with their `--edit` flag often to move between your changes. You
can avoid having to type the `--edit` flag every time you need it by actually
making it the default:

```toml
[ui.movement]
edit = true
```

You can pass the `--no-edit` flag to `prev` and `next` if you find yourself
needing the original behavior.

## List

### Default Template

You can configure the template used when no `-T` is specified.

- `templates.config_list` for `jj config list`

```toml
[templates]
# Use builtin config list template
config_list = "builtin_config_list"
```

If you want to see the config variable origin (type and path) when you do `jj config list`
you can add this to your config:

```toml
[templates]
config_list = "builtin_config_list_detailed"
```

## Log

### Default revisions

You can configure the revisions `jj log` would show when neither `-r` nor any paths are specified.

```toml
[revsets]
# Show commits that are not in `main@origin`
log = "main@origin.."
```

The default value for `revsets.log` is
`'present(@) | ancestors(immutable_heads().., 2) | present(trunk())'`.

### Prioritize Revsets in the Log over @

In some situations the default graph can be hard to read, for example when working with big merges.
To improve this behavior you can configure which revset in the `jj log` graph is displayed on
the left instead of `@`.

The following example will prioritize the change with the description "megamerge" with a fallback
to `trunk()` in case no such change exists:

```toml
[revsets]
log-graph-prioritize = 'coalesce(description("megamerge\n"), trunk())'
```

### Default Template

You can configure the template used when no `-T` is specified.

- `templates.evolog` for `jj evolog`
- `templates.log` for `jj log`
- `templates.show` for `jj show`
- `templates.op_log` for `jj op log`
- `templates.op_show` for `jj op show`

```toml
[templates]
# Use builtin evolog template
evolog = "builtin_evolog_compact"
# Use builtin log template
log = "builtin_log_compact"
# Use builtin show template
show = "builtin_log_detailed"
# Use builtin op log template
op_log = "builtin_op_log_compact"
# Use builtin op log template
op_show = "builtin_op_log_compact"
```

If you want to see the full description when you do `jj log` you can add this to
your config:

```toml
[templates]
log = "builtin_log_compact_full_description"
```

### Graph style

```toml
[ui]
# Possible values: "curved" (default), "square", "ascii", "ascii-large"
graph.style = "square"
```

#### Node style

The symbols used to represent commits or operations can be customized via
templates.

- `templates.log_node` for commits (with `Option<Commit>` keywords)
- `templates.op_log_node` for operations (with `Operation` keywords)

For example:

```toml
[templates]
log_node = '''
coalesce(
  if(!self, "🮀"),
  if(current_working_copy, "@"),
  if(root, "┴"),
  if(immutable, "●", "○"),
)
'''
op_log_node = 'if(current_operation, "@", "○")'
```

### Wrap log content

If enabled, `log`/`evolog`/`op log` content will be wrapped based on
the terminal width.

```toml
[ui]
log-word-wrap = true
```

### Display of commit and change ids

Can be customized by the `format_short_id()` template alias.

```toml
[template-aliases]
# Highlight unique prefix and show at least 12 characters (default)
'format_short_id(id)' = 'id.shortest(12)'
# Just the shortest possible unique prefix
'format_short_id(id)' = 'id.shortest()'
# Show unique prefix and the rest surrounded by brackets
'format_short_id(id)' = 'id.shortest(12).prefix() ++ "[" ++ id.shortest(12).rest() ++ "]"'
# Always show 12 characters
'format_short_id(id)' = 'id.short(12)'
```

To customize these separately, use the `format_short_commit_id()` and
`format_short_change_id()` aliases:

```toml
[template-aliases]
# Uppercase change ids. `jj` treats change and commit ids as case-insensitive.
'format_short_change_id(id)' = 'format_short_id(id).upper()'
```

Operation ids can be customized by the `format_short_operation_id()` alias:

```toml
[template-aliases]
# Always show 12 characters
'format_short_operation_id(id)' = 'id.short(12)'
```

To get shorter prefixes for certain revisions, set `revsets.short-prefixes`:

```toml
[revsets]
# Prioritize the current bookmark
short-prefixes = "(main..@)::"
```

### Relative timestamps

Can be customized by the `format_timestamp()` template alias.

```toml
[template-aliases]
# Full timestamp in ISO 8601 format
'format_timestamp(timestamp)' = 'timestamp'
# Relative timestamp rendered as "x days/hours/seconds ago"
'format_timestamp(timestamp)' = 'timestamp.ago()'
```

`jj op log` defaults to relative timestamps. To use absolute timestamps, you
will need to modify the `format_time_range()` template alias.

```toml
[template-aliases]
'format_time_range(time_range)' = 'time_range.start() ++ " - " ++ time_range.end()'
```

### Author format

Can be customized by the `format_short_signature()` template alias.

```toml
[template-aliases]
# Full email address (default)
'format_short_signature(signature)' = 'signature.email()'
# Both name and email address
'format_short_signature(signature)' = 'signature'
# Username part of the email address
'format_short_signature(signature)' = 'signature.email().local()'
```

### Commit timestamp

Commits have both an "author timestamp" and "committer timestamp". By default,
jj displays the committer timestamp, but can be changed to show the author
timestamp instead.

The function must return a timestamp because the return value will likely be
formatted with `format_timestamp()`.

```toml
[template-aliases]
'commit_timestamp(commit)' = 'commit.author().timestamp()'
```

### Signature format

Can be enabled with `ui.show-cryptographic-signatures`, and
customized with `format_short_cryptographic_signature(sig)` and
`format_detailed_cryptographic_signature(sig)`.

Note that the formatting functions take an `Option<CryptographicSignature>`.
This allows you to emit a custom message if a signature is not present, but
will raise an error if you try to access methods on a signature that is not
available.

```toml
[ui]
# default is false
show-cryptographic-signatures = true

[template-aliases]
'format_short_cryptographic_signature(sig)' = '''
  if(sig,
    sig.status(),
    "(no sig)",
  )
'''
```

## Pager

By default, jj will paginate output that would scroll off the screen. It does
this by passing output through `less -FRX` on most platforms (on Windows it uses
[the pager](#builtin-pager) that is built-in to jj).

Which pager to use can be customized by setting `ui.pager`. When choosing a
pager, ensure that it either supports color codes or that you disable color (see
[Colorizing output](#colorizing-output)).

Examples:

```shell
# Pipe output through `less -FRX` (default on non-Windows platforms)
$ jj config set --user ui.pager "less -FRX"

# Use the built-in pager (default on Windows)
$ jj config set --user ui.pager :builtin

# Use `$PAGER` environment variable if set (on non-Windows platforms)
$ jj config set --user ui.pager '["sh", "-c", "exec ${PAGER:-less -FRX}"]'
```

Additionally, paging behavior can be toggled via `ui.paginate` like so:

```toml
[ui]
# Enable pagination for commands that support it (default)
paginate = "auto"
# Disable all pagination, equivalent to using --no-pager
paginate = "never"
```

### Builtin pager

Our builtin pager is based on
[`streampager`](https://github.com/markbt/streampager/) but is configured within
`jj`'s config. It is configured via the `ui.streampager` table.

#### Key bindings

The built-in pager supports both navigation via arrows and Vim-style navigation.
Beyond that, here are some useful keybindings for the pager:

| Key             | Action                |
| :-------------- | :-------------------- |
| `Ctrl-c` or `q` | Quit                  |
| `h` or `F1`     | Show all key bindings |
| `Esc`           | Close help or prompt  |
| `\`             | Toggle line wrapping  |
| `#`             | Toggle line numbers   |
| `Ctrl-r`        | Toggle the ruler      |

The built-in pager does not support mouse input.

#### Wrapping config

Wrapping performed by the pager happens *in addition to* any
wrapping that `jj` itself does.

```toml
[ui.streampager]
wrapping = "anywhere"  # wrap at screen edge (default)
wrapping = "word"      # wrap on word boundaries
wrapping = "none"      # strip long lines, allow scrolling
                       # left and right like `less -S`
```

#### Auto-exit, clearing the screen on startup or exit

You can configure whether the pager clears the screen on startup or exit, and
whether it quits automatically on short inputs. When the pager auto-quits,
features like word-wrapping are disabled.

```toml
[ui.streampager]
# Do not clear screen on exit. Use a full-screen interface for long
# output only. Like `less -FX`.
interface = "quit-if-one-page"  # (default).
# Always use a full-screen interface, ask the terminal to clear the
# screen on exit. Like `less -+FX`.
interface = "full-screen-clear-output"
# Use the alternate screen if the input is either long or takes more
# than 2 seconds to finish. Similar but not identical to `less -F -+X`.
interface = "quit-quickly-or-clear-output"
```

#### Showing the ruler on startup

```toml
[ui.streampager]
# Start with the ruler showing
show-ruler = true # (default)
# Start with the ruler hidden
show-ruler = false
```

### Processing contents to be paged

If you'd like to pass the output through a formatter e.g.
[`diff-so-fancy`](https://github.com/so-fancy/diff-so-fancy) before piping it
through a pager you must do it using a subshell as, unlike `git` or `hg`, the
command will be executed directly. For example:

```toml
[ui]
pager = ["sh", "-c", "diff-so-fancy | less -RFX"]
```

Some formatters (like [`delta`](https://github.com/dandavison/delta)) require
git style diffs for formatting. You can configure this style of
diff as the default with the `ui.diff-formatter` setting. For example:

```toml
[ui]
pager = "delta"
diff-formatter = ":git"
```

## Aliases

You can define aliases for commands, including their arguments. For example:

```toml
[aliases]
# `jj l` shows commits on the working-copy commit's (anonymous) bookmark
# compared to the `main` bookmark
l = ["log", "-r", "(main..@):: | (main..@)-"]
```

This alias syntax can only run a single jj command. However, you may want to
execute multiple jj commands with a single alias, or run arbitrary scripts that
complement your version control workflow. This can be done, but be aware of the
danger:

!!! warning

    The following technique just provides a convenient syntax for running
    arbitrary code on your system. Using it irresponsibly may cause damage
    ranging from breaking the behavior of `jj undo` to wiping your file system.
    Exercise the same amount of caution while writing these aliases as you would
    when typing commands into the terminal!

    This feature may be removed or replaced by an embedded scripting language in
    the future.

The command `jj util exec` will simply run any command you pass to it as an
argument. Additional arguments are passed through. Here are some examples:

```toml
[aliases]
my-script = ["util", "exec", "--", "my-jj-script"]
#                            ^^^^
# This makes sure that flags are passed to your script instead of parsed by jj.
my-inline-script = ["util", "exec", "--", "bash", "-c", """
set -euo pipefail
echo "Look Ma, everything in one file!"
echo "args: $@"
""", ""]
#    ^^
# This last empty string will become "$0" in bash, so your actual arguments
# are all included in "$@" and start at "$1" as expected.
```

> Note: Shebangs (e.g. `#!/usr/bin/env`) aren't necessary since you're already
> explicitly passing your script into the right shell.

## Editor

The default editor is set via `ui.editor`, though there are several places to
set it. The priority is as follows (environment variables are marked with
a `$`):

`$JJ_EDITOR` > `ui.editor` > `$VISUAL` > `$EDITOR`

Nano is the default editor (Notepad on Windows) in the absence of any other
setting, but you could set it explicitly too.

```toml
[ui]
editor = "pico"
```

To use NeoVim instead:

```toml
[ui]
editor = "nvim"
```

For GUI editors you possibly need to use a `-w` or `--wait`. Some examples:

```toml
[ui]
editor = "code -w"       # VS Code
editor = "code.cmd -w"   # VS Code on Windows
editor = "bbedit -w"     # BBEdit
editor = "subl -n -w"    # Sublime Text
editor = "mate -w"       # TextMate
editor = ["C:/Program Files/Notepad++/notepad++.exe",
    "-multiInst", "-notabbar", "-nosession", "-noPlugin"] # Notepad++
editor = "idea --temp-project --wait"   #IntelliJ
```

Obviously, you would only set one line, don't copy them all in!

## Editing diffs

The `ui.diff-editor` setting affects the default tool used for editing diffs
(e.g.  `jj split`, `jj squash -i`). If it is not set, the special value
`:builtin` is used. It launches a built-in TUI tool (known as [scm-diff-editor])
to edit the diff in your terminal.

[scm-diff-editor]: https://github.com/arxanas/scm-record?tab=readme-ov-file#scm-diff-editor

You can try a different tool temporarily by doing e.g. `jj split --tool meld` or
you can set the option to change the default. This requires that you have an
appropriate tool installed, see for example [the instructions for using
Meld](#using-meld-as-a-diff-editor).

**Suggestion:** If possible, it is recommended to try an external diff tool like
[Meld](#using-meld-as-a-diff-editor) (see below for some other possibilities)
for splitting commits and other diff editing, in addition to the built-in diff
editor. It is good to know the capabilities of both. The built-in diff editor
does not require external tools to be available, is faster for tasks like
picking hunks, and does not require leaving the terminal. External tools give
you the flexibility of picking out portions of lines from the diff or even
arbitrarily editing the text of the files.

If `ui.diff-editor` is a string, e.g. `"meld"`, the arguments will be read from
the following config keys.

```toml
[merge-tools.meld]
# program = "meld"      # Defaults to the name of the tool if not specified
program = "/path/to/meld" # May be necessary if `meld` is not in the PATH
edit-args = ["--newtab", "$left", "$right"]
```

`jj` makes the following substitutions:

- `$left` and `$right` are replaced with the paths to the left and right
  directories to diff respectively.

- If no `edit-args` are specified, `["$left", "$right"]` are set by default.

- If `edit-args = []`, `jj` will refuse to use this tool for diff editing. This is a way to explicitly state that a certain tool (e.g. `mergiraf`) does not work for diff editing.

Finally, `ui.diff-editor` can be a list that specifies a command and its arguments.

Some examples:

```toml
[ui]
# Use merge-tools.meld.edit-args
diff-editor = "meld"  # Or `kdiff3`, or `diffedit3`, ...
# Specify edit-args inline
diff-editor = ["/path/to/binary", "--be-helpful", "$left", "$right"]
# Equivalent to ["binary", "$left", "$right"] arguments by default
diff-editor = "binary"
```

### Experimental 3-pane diff editing

We offer two special "3-pane" diff editor configs:

- `meld-3`, which requires installing [Meld](https://meldmerge.org/), and
- `diffedit3`, which requires installing [`diffedit3`](https://github.com/ilyagr/diffedit3/releases).

`Meld` is a graphical application that is recommended, but can be difficult to
install in some situations. `diffedit3` is designed to be easy to install and to
be usable in environments where Meld is difficult to use (e.g. over SSH via port
forwarding). `diffedit3` starts a local server that can be accessed via a web
browser, similarly to [Jupyter](https://jupyter.org/).

There is also the `diffedit3-ssh` which is similar to `diffedit3` but does not
try to open the web browser pointing to the local server (the URL
printed to the terminal) automatically. `diffedit3-ssh` also always uses ports in between
17376-17380 and fails if they are all busy. This can be useful when working
over SSH. Open the fold below for more details of how to set that up.

<details>
<summary> Tips for using `diffedit3-ssh` over SSH </summary>

To use `diffedit3` over SSH, you need to set up port forwarding. One way to do
this is to start SSH as follows (copy-paste the relevant lines):

```shell
ssh -L 17376:localhost:17376 \
    -L 17377:localhost:17377 \
    -L 17378:localhost:17378 \
    -L 17379:localhost:17379 \
    -L 17380:localhost:17380 \
    myhost.example.com
```

`diffedit3-ssh` is set up to use these 5 ports by default. Usually, only the
first of them will be used. The rest are used if another program happens to use
one of them, or if you run multiple instances of `diffedit3` at the same time.

Another way is to add a snippet to `~/.ssh/config`:

```ssh-config
Host myhost
    User     myself
    Hostname myhost.example.com
    LocalForward 17376 localhost:17376
    LocalForward 17377 localhost:17377
    LocalForward 17378 localhost:17378
    LocalForward 17379 localhost:17379
    LocalForward 17380 localhost:17380
```

With that configuration, you should be able to simply `ssh myhost`.

</details>

Setting either `ui.diff-editor = "meld-3"` or `ui.diff-editor = "diffedit3"`
will result in the diff editor showing 3 panes: the diff on the left and right,
and an editing pane in the middle. This allow you to see both sides of the
original diff while editing.

If you use `ui.diff-editor = "meld-3"`, note that you can still get the 2-pane
Meld view using `jj diff --tool meld`. `diffedit3` has a button you can use to
switch to a 2-pane view.

To configure other diff editors in this way, you can include `$output` together
with `$left` and `$right` in `merge-tools.TOOL.edit-args`. `jj` will replace
`$output` with the directory where the diff editor will be expected to put the
result of the user's edits. Initially, the contents of `$output` will be the
same as the contents of `$right`.

### `JJ-INSTRUCTIONS`

When editing a diff, jj will include a synthetic file called `JJ-INSTRUCTIONS`
in the diff with instructions on how to edit the diff. Any changes you make to
this file will be ignored. To suppress the creation of this file, set
`ui.diff-instructions = false`.

### Using Meld as a diff editor

[Meld](https://meldmerge.org) is a nice and polished free diff editor. It can be
obtained as follows:

- **Linux:** use your favorite package manager, e.g. `sudo apt install meld`.

- **Windows:** Meld can be downloaded from <https://meldmerge.org/>.

- **Mac OS:** Install Homebrew and run `brew install --cask meld`.
  This will install both an app in `/Applications/Meld.app` and the command-line
  `meld` command that `jj` uses. You can read about [more details and other
  options](https://gist.github.com/ilyagr/1b40f6061d8ad320cee4c12843df1a23) but,
  as of this writing, this is by far the easiest.

`jj` has two diff editing configurations that use Meld: `meld` for a 2-pane view
and `meld-3` for a [three-pane view](#experimental-3-pane-diff-editing).

There is also a `meld` [merge tool](#3-way-merge-tools-for-conflict-resolution)
that can be useful, but does not support displaying the merge base while
merging.

### Using Vim as a diff editor

Using `ui.diff-editor = "vimdiff"` is possible but not recommended. For a better
experience, you can follow [instructions from the Wiki] to configure the
[DirDiff Vim plugin] and/or the [vimtabdiff Python script].

[instructions from the Wiki]: https://github.com/jj-vcs/jj/wiki/Vim,-Neovim#using-vim-as-a-diff-tool

[DirDiff Vim plugin]: https://github.com/will133/vim-dirdiff
[vimtabdiff Python script]: https://github.com/balki/vimtabdiff

## 3-way merge tools for conflict resolution

The `ui.merge-editor` key specifies the tool used for three-way merge tools
by `jj resolve`. For example:

```toml
[ui]
# Use merge-tools.meld.merge-args
merge-editor = "meld"  # Or "vscode" or "vscodium" or "kdiff3" or "vimdiff"
# Specify merge-args inline
merge-editor = ["meld", "$left", "$base", "$right", "-o", "$output"]
```

The following tools can be used out of the box, as long as they are installed:
- "kdiff3"
- "meld"
- "mergiraf"
- "smerge"
- "vimdiff"
- "vscode"
- "vscodium"

Using VS Code as a merge tool works well with VS Code's [Remote
Development](https://code.visualstudio.com/docs/remote/remote-overview)
functionality, as long as `jj` is called from VS Code's terminal.

### Setting up a custom merge tool

To use a different tool named `TOOL`, the arguments to pass to the tool MUST be
specified either inline or in the `merge-tools.TOOL.merge-args` key. As an
example of how to set this key and other tool configuration options, here is
the out-of-the-box configuration of the three default tools. (There is no need
to copy it to your config file verbatim, but you are welcome to customize it.)

```toml
[merge-tools.kdiff3]
# program  = "kdiff3"     # Defaults to the name of the tool if not specified
merge-args = ["$base", "$left", "$right", "-o", "$output", "--auto"]
[merge-tools.meld]
merge-args = ["$left", "$base", "$right", "-o", "$output", "--auto-merge"]

[merge-tools.vimdiff]
merge-args = ["-f", "-d", "$output", "-M",
    "$left", "$base", "$right",
    "-c", "wincmd J", "-c", "set modifiable",
    "-c", "set write"]
program = "vim"
merge-tool-edits-conflict-markers = true    # See below for an explanation
```

`jj` makes the following substitutions:

- `$output` (REQUIRED) is replaced with the name of the file that the merge tool
  should output. `jj` will read this file after the merge tool exits.

- `$left` and `$right` are replaced with the paths to two files containing the
  content of each side of the conflict.

- `$base` is replaced with the path to a file containing the contents of the
  conflicted file in the last common ancestor of the two sides of the conflict.

- `$marker_length` is replaced with the length of the conflict markers which
  should be used for the file. This can be useful if the merge tool parses
  and/or generates conflict markers. Usually, `jj` uses conflict markers of
  length 7, but they can be longer if necessary to make parsing unambiguous.

- `$path` is replaced with the path in the repository at which the file
  will be eventually stored. It is relative to the root directory of the
  repository and uses `/` as separators.

Unlike `diff-args` or `edit-args`, there is no default value for `merge-args`.
If `merge-args` are not specified, the tool cannot be used for conflict
resolution.

### Editing conflict markers with a tool or a text editor

By default, the merge tool starts with an empty output file. If the tool puts
anything into the output file and exits with the 0 exit code,
`jj` assumes that the conflict is fully resolved, while if the tool exits with
a non-zero exit code, `jj` assumes that the merge should be canceled.
This is appropriate for most graphical merge tools.

For merge tools which try to automatically resolve conflicts without user input,
this behavior may not be desired. For instance, some automatic merge tools use
an exit code of 1 to indicate that some conflicts were unable to be resolved and
that the output file should contain conflict markers. In that case, you could
set the config option `merge-tools.TOOL.merge-conflict-exit-codes = [1]` to tell
`jj` to expect conflict markers in the output file if the exit code is 1. If a
merge tool produces output using Git's "diff3" conflict style, `jj` should be
able to parse it correctly, so many Git merge drivers should be usable with `jj`
as well.

Some tools (e.g. `vimdiff`) can present a multi-way diff but don't resolve
conflict themselves. When using such tools, `jj`
can help you by populating the output file with conflict markers before starting
the merge tool (instead of leaving the output file empty and letting the merge
tool fill it in). To do that, set the
`merge-tools.vimdiff.merge-tool-edits-conflict-markers = true` option.

With this option set, if the output file still contains conflict markers after
the conflict is done, `jj` assumes that the conflict was only partially resolved
and parses the conflict markers to get the new state of the conflict. The
conflict is considered fully resolved when there are no conflict markers left.
The conflict marker style can also be customized per tool using the
`merge-tools.TOOL.conflict-marker-style` option, which takes the same values as
[`ui.conflict-marker-style`](#conflict-marker-style).

## Code formatting and other file content transformations

The `jj fix` command allows you to efficiently rewrite files in complex commit
graphs with no risk of introducing conflicts, using tools like `clang-format` or
`prettier`. The tools run as subprocesses that take a file content on standard
input and repeat it, with any desired changes, on standard output.

This enables the command to format many versions of the same file concurrently
and without touching on the working copy. The local files are not and must not
be used.

The file is only rewritten if the subprocess produces a successful exit code.

### Configuration

Tools are defined in a table where the keys are arbitrary identifiers and
the values have the following properties:
 - `command`: The arguments used to run the tool. The first argument is the
   path to an executable file. Arguments can contain these variables that will
   be replaced:
   - `$root` will be replaced with the workspace root path (the directory
     containing the .jj directory).
   - `$path` will be replaced with the repo-relative path of the file being
     fixed. It is useful to provide the path to tools that include the path
     in error messages, or behave differently based on the directory or file
     name.
 - `patterns`: List of filesets (see: `jj help -k filesets`), determining
   which files the tool will affect based on their path. If this list is
   empty, no files will be affected by the tool. If there are multiple
   patterns, the tool is applied only once to each file in the union of the
   patterns.
 - `enabled`: Enables or disables the tool. If omitted, the tool is enabled.
   This is useful for defining disabled tools in user configuration that can
   be enabled in individual repositories with one config setting.

`jj fix` provides the file content anonymously on standard input, but the name
of the file being formatted may be important for include sorting or other output
like error messages. To address this, you can use the `$root` and `$path` in
your arguments.

### Enforce coding style rules

Suppose you want to use `clang-format` to format your `*.c` and `*.h` files,
as well as sorting their `#include` directives.

```toml
[fix.tools.clang-format]
command = ["/usr/bin/clang-format", "--sort-includes", "--assume-filename=$path"]
patterns = ["glob:'**/*.c'",
            "glob:'**/*.h'"]
```

### Sort and remove duplicate lines from a file

`jj fix` can also be used with tools that are not considered code formatters.

Suppose you have a list of words in a text file in your repository, and you want
to keep the file sorted alphabetically and remove any duplicate words.

```toml
[fix.tools.sort-word-list]
command = ["sort", "-u"]
patterns = ["word_list.txt"]
```

### Tools stored inside the workspace

Some fix tools may be stored inside the workspace. For example, a binary may be
stored inside `node_modules`. Use the `$root` variable to create an absolute
path to such a program:

```toml
[fix.tools.biome]

# Linux and macOS
command = ["$root/node_modules/@biomejs/cli-linux-x64/biome"]

# Windows
command = ["$root\\node_modules\\@biomejs\\cli-win32-x64\\biome.exe"]
```

### Execution order of tools

If two or more tools affect the same file, they are executed in the ascending
lexicographical order of their configured names. Any tool, but the first one to
be executed, get as input the content of the file produced by the previous
tool. This will remain as a tie breaker if other ordering mechanisms are
introduced in the future.

If you use numbers in tool names to control execution order, remember to
include enough leading zeros so that, for example, `09` sorts before `10`.

Suppose you want to keep only the 10 smallest numbers in a text file that
contains one number on each line. This can be accomplished with `sort` and
`head`, but execution order is important.

```toml
[fix.tools.1-sort-numbers-file]
command = ["sort", "-n"]
patterns = ["numbers.txt"]

[fix.tools.2-truncate-numbers-file]
command = ["head", "-n", "10"]
patterns = ["numbers.txt"]
```

### Disabling and enabling tools

Tools can be disabled and enabled with the optional `enabled` config. This
allows you to define tools globally but enable them only for specific
repositories.

In the user configuration, define a disabled tool for running rustfmt:

```toml
[fix.tools.rustfmt]
enabled = false
command = ["rustfmt", "--emit", "stdout"]
patterns = ["glob:'**/*.rs'"]
```

Then to use the tool in a specific repository, set the `enabled` config:

```shell
$ jj config set --repo fix.tools.rustfmt.enabled true
```

## Commit Signing

`jj` can be configured to sign and verify the commits it creates using either
GnuPG or SSH signing keys.

To do this you need to configure a signing backend.

Setting the backend to `"none"` disables signing.

### GnuPG Signing

```toml
[signing]
behavior = "own"
backend = "gpg"
## You can set `key` to anything accepted by `gpg -u`
## If not set then defaults to the key associated with `user.email`
# key = "4ED556E9729E000F"
# key = "signing@example.com"
```

By default the gpg backend will look for a `gpg` binary on your path. If you want
to change the program used or specify a path to `gpg` explicitly you can set:

```toml
[signing]
backends.gpg.program = "gpg2"
```

Also by default the gpg backend will consider key expiry when verifying commit signatures.
To consider expired keys as valid you can set:

```toml
[signing]
backends.gpg.allow-expired-keys = true
```

#### PKCS#12 Certificates

PKCS#12 certificates can be used to sign commits using the `gpgsm` backend.

```toml
[signing]
behavior = "own"
backend = "gpgsm"
## You can set `key` to anything accepted by `gpgsm -u`
## If not set then defaults to the key associated with `user.email`
# key = "4ED556E9729E000F"
# key = "signing@example.com"
```

By default the gpgsm backend will look for a `gpgsm` binary on your path. If you want
to change the program used or specify a path to `gpgsm` explicitly you can set:

```toml
[signing]
backends.gpgsm.program = "gpgsm"
```

Also by default the gpgsm backend will consider key expiry when verifying commit signatures.
To consider expired keys as valid you can set:

```toml
[signing]
backends.gpgsm.allow-expired-keys = true
```

### SSH Signing

```toml
[signing]
behavior = "own"
backend = "ssh"
key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGj+J6N6SO+4P8dOZqfR1oiay2yxhhHnagH52avUqw5h"
## You can also use a path instead of embedding the key
# key = "~/.ssh/id_for_signing.pub"
```

By default the ssh backend will look for a `ssh-keygen` binary on your path. If you want
to change the program used or specify a path to `ssh-keygen` explicitly you can set:

```toml
[signing]
backends.ssh.program = "/path/to/ssh-keygen"
```

When verifying commit signatures the ssh backend needs to be provided with an allowed-signers
file containing the public keys of authors whose signatures you want to be able to verify.

You can find the format for this file in the
[ssh-keygen man page](https://man.openbsd.org/ssh-keygen#ALLOWED_SIGNERS). This can be provided
as follows:

```toml
[signing]
backends.ssh.allowed-signers = "/path/to/allowed-signers"
```

Additionally, an SSH KRL or list of revoked public keys (see
[ssh-keygen man page](https://man.openbsd.org/ssh-keygen#KEY_REVOCATION_LISTS)) can be provided
with the `revocation-list` option. If a public key is found in this file then any signature
relating to it is marked as invalid.

```toml
[signing]
backends.ssh.revocation-list = "/path/to/revocation-list"
```

### Manually signing commits

You can use [`jj sign`](./cli-reference.md#jj-sign)/[`jj unsign`](./cli-reference.md#jj-unsign)
to sign/unsign commits manually.

!!! warning

    `jj sign` always signs commits, even if they are already signed by the
    user. While this is cumbersome for users signing via hardware devices, we
    cannot reliably check if a commit is already signed without creating a
    signature (see [this issue](https://github.com/jj-vcs/jj/issues/5786)).

### Automatically signing commits

The `signing.behavior` configuration option has four different options for what
to do with signing commits on modification of a change (e.g., rebasing or edits).

- `drop`: do not automatically sign; if a change was signed before
  modification, drop that signing after modification.
- `keep`: if a change was signed before modification, and it was authored by
  you, attempt to sign it again after the modification.
- `own`: sign all commits that were authored by you when you modify them.
- `force`: sign all commits after modification, always, even if you are not the
  author.

Instead of signing all commits during creation when `signing.behavior` is
set to `own`, the `git.sign-on-push` configuration can be used to sign
commits only upon running `jj git push`. All mutable unsigned commits
being pushed will be signed prior to pushing. This might be preferred if the
signing backend requires user interaction or is slow, so that signing is
performed in a single batch operation.

```toml
# Configure signing backend as before, but lazily signing only on push.
[signing]
behavior = "drop"
backend = "ssh"
key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGj+J6N6SO+4P8dOZqfR1oiay2yxhhHnagH52avUqw5h"

[git]
sign-on-push = true
```

## Commit Signature Verification

By default signature verification and display is **disabled** as it incurs a
performance cost when rendering medium to large change logs. You can enable it
by setting `ui.show-cryptographic-signatures` to true in your configuration.

If you want to display commit signatures in your templates, you can use
`commit.signature()` (see [Commit type](./templates.md#commit-type)). The
returned [CryptographicSignature
Type](./templates.md#cryptographicsignature-type) provides methods to retrieve
signature details.

## Git settings

### Default colocation

When creating a Git-backed Jujutsu repository, they use "colocated" mode by
default, which places the `.git` directory next to the `.jj` directory.
Colocation allows some amount of two-way interoperability, but it can perform
worse in large repos.

The setting `git.colocate` is a boolean option that controls whether or not the
`jj git init` and `jj git clone` commands should create colocated workspace by
default. Set `git.colocate` to `false` to disable it.

See [Colocated Jujutsu/Git workspaces](git-compatibility.md#colocated-jujutsugit-repos)
for more information.

### Default remotes for `jj git fetch` and `jj git push`

By default, if a single remote exists it is used for `jj git fetch` and `jj git
push`; however if multiple remotes exist, the default remote is assumed to be
named `"origin"`, just like in Git. Sometimes this is undesirable, e.g. when you
want to fetch from a different remote than you push to, such as a GitHub fork.

To change this behavior, you can modify the [repository
configuration](#config-files-and-toml) variable `git.fetch`, which can be a
single remote, or a list of remotes to fetch from multiple places:

```sh
jj config set --repo git.fetch "upstream"
jj config set --repo git.fetch '["origin", "upstream"]'
```

By default, the specified pattern matches remote names with glob syntax. You can
also use other [string pattern syntax](revsets.md#string-patterns):

```sh
jj config set --repo git.fetch "regex:'^(remote|upstream)'"
jj config set --repo git.fetch '["remote*", "upstream*"]'
```

Similarly, you can also set the variable `git.push` to cause `jj git push` to
push to a different remote:

```sh
jj config set --repo git.push "github"
```

Note that unlike `git.fetch`, `git.push` can currently only be a single remote.
This is not a hard limitation, and could be changed in the future if there is
demand.

### Automatic tracking of bookmarks

You can configure which bookmarks to track automatically per remote, using the
`remotes.<name>.auto-track-bookmarks` config. The value is a
[string pattern](./revsets.md#string-patterns) that matches the names of the
bookmarks to track. This setting is applied to all new bookmarks, including ones
created locally and ones fetched from the remote. For example:

```toml
[remotes.origin]
auto-track-bookmarks = "*"
```

This will simply track all bookmarks for the remote "origin". There are various
reasons to restrict which bookmarks to track:

- When collaborating with other people via the same remote, you may not want to
  track all the bookmarks of your collaborators. Similarly, you may not want to
  push some of your bookmarks to the remote at all; these may only be intended
  for local use. Many people use a "personal prefix" in their bookmark names.
  This marks a bookmark as belonging to one person, making it possible to track
  and push only bookmarks with that prefix. For example, Alice may set her
  configuration like so:

  ```toml
  [remotes.origin]
  auto-track-bookmarks = "alice/*"
  ```

  That way, bookmarks pushed by other people (who probably use a different
  prefix or none at all) are not tracked automatically. At the same time, Alice
  can create bookmarks without the prefix for local-only use. You can also
  configure Jujutsu to use your prefix for generated bookmark names; see the
  section
  ["Generated bookmark names on push"](#generated-bookmark-names-on-push).

- Another reason to restrict the bookmarks to track may be that you're not
  collaborating with people using the same remote, but a different one. For
  example, if you make a fork on GitHub, your fork will usually be called
  "origin", while the repository you forked from is usually called "upstream".
  In that case, you may want to track all bookmarks from your fork, but only the
  "main" bookmark from upstream. Here's an example how to achieve that:

  ```toml
  [remotes.origin]
  auto-track-bookmarks = "*"
  [remotes.upstream]
  auto-track-bookmarks = "main"
  ```

- Lastly, you may be working on various projects with different conventions for
  bookmark names. In that case, it can be handy to apply different configuration
  to different (groups of) repositories. Read about how to do that in the
  section ["Conditional variables"](#conditional-variables).

### Automatic local bookmark creation on `jj git clone`

When cloning a new Git repository, `jj` by default creates a local bookmark
tracking the default remote bookmark (such as `main` for `main@origin`.) If you
aren't going to update the `main` bookmark locally, the tracking bookmark isn't
necessary.

This behavior can be disabled by

```toml
[git]
track-default-bookmark-on-clone = false
```

### Abandon commits that became unreachable in Git

By default, when `jj` imports refs from Git, it will look for commits that used
to be [reachable][reachable] but no longer are reachable. Those commits will
then be abandoned, and any descendant commits will be rebased off of them (as
usual when commits are abandoned). You can disable this behavior and instead
leave the Git-unreachable commits in your repo by setting:

```toml
[git]
abandon-unreachable-commits = false
```

[reachable]: https://git-scm.com/docs/gitglossary/#Documentation/gitglossary.txt-aiddefreachableareachable

### Generated bookmark names on push

`jj git push --change` generates bookmark names with a prefix of "push-" by
default. You can pick a different prefix and formatting by setting the
`templates.git_push_bookmark` template. For example:

```toml
[templates]
git_push_bookmark = '"martinvonz/push-" ++ change_id.short()'
```

This template should include expressions like `change_id` to generate unique and
stable bookmark.

### Set of private commits

You can configure the set of private commits by setting `git.private-commits` to
a revset. The value is a revset of commits that Jujutsu will refuse to push. If
unset, all commits are eligible to be pushed.

```toml
[git]
# Prevent pushing work in progress or anything explicitly labeled "private"
private-commits = "description('wip:*') | description('private:*')"
```

If a commit is in `git.private-commits` but is already on the remote, then it is
not considered a private commit. Commits that are immutable are also excluded
from the private set.

Private commits prevent their descendants from being pushed, since doing so
would require pushing the private commit as well.

### Git subprocessing behavior

Git remote interactions are handled by spawning a `git` subprocess.
If `git` is not on your OS path, or you want to specify a particular binary,
you can:

```toml
[git]
executable-path = "/path/to/git"
```

## Merge settings

### Granularity of hunks

`jj` by default resolves content conflicts by splitting text into line-level
hunks and merge them. This can be configured to split hunks further into
word-level hunks.

* `line`: split into line hunks (default)
* `word`: split into word hunks

```toml
[merge]
hunk-level = "line"
```

### Resolution of same-change conflicts

`jj` by default resolves conflicts if all sides made the same change. This
matches what Git and Mercurial do (in the 3-way case at least), but not what
Darcs does. It also means that repeated 3-way merging of multiple trees may give
different results depending on the order of merging. To turn it off, set
`same-change = "keep"`.

* `keep`: leave same-change conflict unresolved
* `accept`: resolve same-change conflict to new value (default)

```toml
[merge]
same-change = "accept"
```

## Filesystem monitor

In large repositories, it may be beneficial to use a "filesystem monitor" to
track changes to the working copy. This allows `jj` to take working copy
snapshots without having to rescan the entire working copy.

This is governed by the `fsmonitor.backend` option. Currently, the valid values
are `"none"` or `"watchman"`.

### Watchman

To configure the Watchman filesystem monitor, set
`fsmonitor.backend = "watchman"`. Ensure that you have [installed the Watchman
executable on your system](https://facebook.github.io/watchman/docs/install).

You can configure `jj` to use watchman triggers to automatically create
snapshots on filesystem changes by setting
`fsmonitor.watchman.register-snapshot-trigger = true`.

You can check whether Watchman is enabled and whether it is installed correctly
using `jj debug watchman status`.

Note: `watchman` heavily uses `inotify` and sets up a user watch per-file. On
large repositories, this may cause `watchman` to fail and commands like
`jj status` to take longer than expected. If you experience this run
`jj debug watchman status` and tune your `inotify` limits.

## Snapshot settings

### Paths to automatically track

All new files in the working copy that don't match the ignore patterns are
tracked by default. You can set the `snapshot.auto-track` to set which paths
get automatically tracked when they're added to the working copy. See the
[fileset documentation](filesets.md) for the syntax. Files with paths matching
[ignore files](working-copy.md#ignored-files) are never tracked automatically.

If you set `snapshot.auto-track` to a non-default value, untracked files can be
tracked with `jj file track`.

You can use `jj file untrack` to untrack a file while keeping it in the working
copy. However, first [ignore](working-copy.md#ignored-files) them or remove them
from the `snapshot.auto-track` patterns; otherwise they will be immediately
tracked again.

### Maximum size for new files

By default, as an anti-footgun measure, `jj` will refuse to add new files to the
snapshot that are larger than a certain size; the default is 1MiB. This can be
changed by setting `snapshot.max-new-file-size` to a different value. For
example:

```toml
[snapshot]
max-new-file-size = "10MiB"
# the following is equivalent
max-new-file-size = 10485760
```

The value can be specified using a human readable string with typical suffixes;
`B`, `MiB`, `GB`, etc. By default, if no suffix is provided, or the value is a
raw integer literal, the value is interpreted as if it were specified in bytes.

Files that already exist in the working copy are not subject to this limit.

Setting this value to zero will disable the limit entirely.

### Automatic update of stale working copies

When a working copy becomes stale (meaning the working copy's recorded commit is
no longer the current commit for that workspace), `jj` will normally prompt you
to update it with `jj workspace update-stale`. You can configure `jj` to
automatically update stale working copies by setting:

```toml
[snapshot]
auto-update-stale = true
```

This is particularly useful if you have [multiple workspaces](working-copy.md#workspaces)
and want to avoid manually updating each one.

For more information on stale working copies, see the [working copy
documentation](working-copy.md#stale-working-copy).

## Working copy settings

### EOL conversion settings

This settings serves the same purpose as the [`core.autocrlf`][git-autocrlf] git
config.

The line endings conversion won't be applied to files detected as binary files
via a heuristics[^1] regardless of the settings. This is similar to git.

```toml
[working-copy]
# No EOL conversion. Similar to core.autocrlf = false.
eol-conversion = "none"
# Apply CRLF to LF EOL conversion when we check files in the backend store from
# the local file system but not apply EOL conversion when we check out the code
# from the backend store to the local file system. Similar to core.autocrlf =
# input.
eol-conversion = "input"
# Setting this to "input-output" if you want to have CRLF line endings in your
# working directory and the repository has LF line endings. Similar to
# core.autocrlf = true.
eol-conversion = "input-output"
```

[git-autocrlf]: https://git-scm.com/book/en/v2/Customizing-Git-Git-Configuration#_core_autocrlf
[gitoxide-is-binary]: https://github.com/GitoxideLabs/gitoxide/blob/073487b38ed40bcd7eb45dc110ae1ce84f9275a9/gix-filter/src/eol/utils.rs#L98-L100
[git-is-binary]: https://github.com/git/git/blob/f1ca98f609f9a730b9accf24e5558a10a0b41b6c/convert.c#L94-L103
[^1]: To detect if a file is binary, Jujutsu currently checks if there is NULL
      byte in the file which is different from the algorithm of
      [`gitoxide`][gitoxide-is-binary] or [`git`][git-is-binary]. Jujutsu
      doesn't plan to align the binary detection logic with git.

### Respect or ignore executable bit permission changes

Whether to respect or ignore changes to the executable bit for files on Unix.
This option is unused on Windows.

```toml
[working-copy]
exec-bit-change = "respect" | "ignore" | "auto" (default)
```

On Unix systems, files have a permission bit for whether they are executable as
scripts or binary code. Jujutsu stores this state in the repository and will
update it for files as you operate on a repository. If you set your working
copy to a commit where a file is recorded as executable or not, `jj` will
adjust the permission of that file. If you change a file's executable bit
through the filesystem, `jj` will record that change when taking a snapshot.

Setting this to `"ignore"` will make Jujutsu ignore the executable bit on the
filesystem when updating the state for the repository. In addition, `jj` will
not attempt to modify a file's executable bit and will add new files as
"not executable." This is already the behavior on Windows, and having the
option to enable this behavior is useful for Unix users dual-booting Windows,
Windows users accessing files from WSL, or anyone experimenting with other
filesystem configurations.

On Unix if `"auto"` is set (the default), `jj` will try to detect whether the
filesystem supports changing executable bits to choose between `"respect"` or
`"ignore"`. On errors, we assume `"respect"`, except if permission was denied
which will assume `"ignore"`.

On Windows, files have no executable bit so this option is unused.

You can always use `jj file chmod` to update the recorded executable bit for a
file manually. If this option is `"respect"`, `jj` will also attempt to
propagate that change to the filesystem.

Note that if you modify a file's executable bit before changing this setting
from `"ignore"` or  `"auto"` to `"respect"`, `jj` may not update the stored
executable bit until you modify the file's contents or update its modification
time, e.g. with `touch`.

## Ways to specify `jj` config: details

### User config files

An easy way to find the user config file/directory is:

```bash
jj config path --user
```

On all platforms, the user's global `jj` configurations are by default loaded in
the following precedence order (with later configs overriding earlier ones):

- `$HOME/.jjconfig.toml`
- `<PLATFORM_SPECIFIC>/jj/config.toml` (preferred)
- `<PLATFORM_SPECIFIC>/jj/conf.d/*.toml`

where `$HOME` represents the user's home directory (`%USERPROFILE%` on Windows),
and `<PLATFORM_SPECIFIC>` represents the platform-specific configuration
directory shown in the table below. The platform-specific location is
recommended for better integration with platform services.

The files in the `conf.d` directory are loaded in lexicographic order. This allows
configs to be split across multiple files and combines well
with [Conditional Variables](#conditional-variables).

| Platform        | Location of `<PLATFORM_SPECIFIC>` dir | Example config file location                              |
| :-------------- | :------------------------------------ | :-------------------------------------------------------- |
| Linux and macOS | `$XDG_CONFIG_HOME` or `$HOME/.config` | `/home/alice/.config/jj/config.toml`                      |
| Windows         | `{FOLDERID_RoamingAppData}`           | `C:\Users\Alice\AppData\Roaming\jj\config.toml`           |

The location of the `jj` user config files/directories can also be overridden with the
`JJ_CONFIG` environment variable. If it is not empty, it will be used instead
of any configuration files in the default locations. If it is a path to a TOML
file, then that file will be loaded instead. If it is a path to a directory,
then all the TOML files in that directory will be loaded in lexicographic order
and merged. Multiple paths can be specified by separating them with a
platform-specific path separator (`:` on Unix-like systems, `;` on Windows).

For example, the following could be used to run `jj` without loading any user configs:

```bash
JJ_CONFIG= jj log       # Ignores any settings specified in the config file.
```

### JSON Schema Support

Many popular editors support TOML file syntax highlighting and validation. To
enable schema validation in your editor, add this line at the top of your TOML
config files:

```toml
#:schema https://docs.jj-vcs.dev/latest/config-schema.json
```

This enables features like:

- Autocomplete for config keys
- Type checking of values
- Documentation on hover
- Validation of settings

Here are some popular editors with TOML schema validation support:

- VS Code
  - Install [Even Better TOML](https://marketplace.visualstudio.com/items?itemName=tamasfe.even-better-toml)

- Neovim/Vim
  - Use with [nvim-lspconfig](https://github.com/neovim/nvim-lspconfig) and [taplo](https://github.com/tamasfe/taplo)

- Helix
  - Install [taplo](https://github.com/tamasfe/taplo)

- JetBrains IDEs (IntelliJ, PyCharm, etc)
  - Install [TOML](https://plugins.jetbrains.com/plugin/8195-toml) plugin

- Emacs
  - Install [lsp-mode](https://github.com/emacs-lsp/lsp-mode) and [toml-mode](https://github.com/dryman/toml-mode.el)
  - Configure [taplo](https://github.com/tamasfe/taplo) as the LSP server

### Specifying config on the command-line

You can use one or more `--config`/`--config-file` options on the command line
to specify additional configuration settings. This overrides settings defined in
config files or environment variables. For example,

```shell
# Must not have spaces around the `=`
jj --config ui.color=always --config ui.diff-editor=meld split
```

Config value should be specified as a TOML expression. If string value isn't
enclosed by any TOML constructs (such as array notation), quotes can be omitted.
Here is an example with more advanced TOML constructs:

```shell
# Single quotes and the '\' are interpreted by the shell and assume a Unix shell
# Double quotes are passed to jj and are parsed as TOML syntax
jj log --config \
  'template-aliases."format_timestamp(timestamp)"="""timestamp.format("%Y-%m-%d %H:%M %:::z")"""'
```

To load an entire TOML document, use `--config-file`:

```shell
jj --config-file=extra-config.toml log
```

### Conditional variables

You can conditionally enable config variables by using `--when`.

#### Using `[[--scope]]` tables

Variables defined in `[[--scope]]` tables are expanded to the root table.
`--when` specifies the condition to enable the scope table.

If no conditions are specified, the table is always enabled. If multiple
conditions are specified, their intersection is used.

```toml
[user]
name = "YOUR NAME"
email = "YOUR_DEFAULT_EMAIL@example.com"

# override user.email if the repository is located under ~/oss
[[--scope]]
--when.repositories = ["~/oss"]
[--scope.user]
email = "YOUR_OSS_EMAIL@example.org"

# override ui.pager on specific machines
[[--scope]]
--when.hostnames = ["work-laptop", "work-desktop"]
[--scope.ui]
pager = "delta"

# disable pagination for `jj status`, use `delta` for `jj diff` and `jj show`
[[--scope]]
--when.commands = ["status"]
[--scope.ui]
paginate = "never"
[[--scope]]
--when.commands = ["diff", "show"]
[--scope.ui]
pager = "delta"
```

#### Using multiple files

`--when` can also be used on the top level of a TOML file, which is convenient
when splitting your config across multiple files.
The behavior of conditions are the same as when using `[[--scope]]` tables.

```toml
# In $XDG_CONFIG_HOME/jj/config.toml
[user]
name = "YOUR NAME"
email = "YOUR_DEFAULT_EMAIL@example.com"
```

```toml
# In $XDG_CONFIG_HOME/jj/conf.d/work.toml
--when.repositories = ["~/the/work/repo"]

[user]
email = "YOUR_WORK_EMAIL@workplace.com"

[revset-aliases]
work = "heads(::@ ~ description(''))::"

[aliases]
wip = ["log", "-r", "work"]
```

#### Available condition keys

* `--when.repositories`: List of paths to match the repository path prefix.

  Paths should be absolute. Each path component (directory or file name, drive
  letter, etc.) is compared case-sensitively on all platforms. A path starting
  with `~` is expanded to the home directory. On Windows, directory separator may
  be either `\` or `/`. (Beware that `\` needs escape in double-quoted strings.)

  Use `jj root` to see the workspace root directory. Note that the repository path
  is in the main workspace if you're using multiple workspaces with `jj
  workspace`.

* `--when.workspaces`: List of paths to match the workspace path prefix.

  The same concerns about the path as for `--when.repositories` applies.

  Use `jj root` to see the workspace root directory.

* `--when.hostnames`: List of hostnames to match against the `operation.hostname`
  config setting.

  Hostnames are compared case-sensitively and must match exactly.

  ```toml
  --when.hostnames = ["work-laptop"]               # matches only "work-laptop"
  --when.hostnames = ["home-desktop", "laptop"]    # matches "home-desktop" OR "laptop"
  ```

* `--when.commands`: List of subcommands to match.

  Subcommands are space-separated and matched by prefix.

  ```toml
  --when.commands = ["file"]        # matches `jj file show`, `jj file list`, etc
  --when.commands = ["file show"]   # matches `jj file show` but *NOT* `jj file list`
  --when.commands = ["file", "log"] # matches `jj file` *OR* `jj log` (or subcommand of either)
  ```

* `--when.platforms`: List of platforms to match.

  The values are defined by both
  [`std::env::consts::FAMILY`](https://doc.rust-lang.org/std/env/consts/constant.FAMILY.html)
  and
  [`std::env::consts::OS`](https://doc.rust-lang.org/std/env/consts/constant.OS.html).

  ```toml
  --when.platforms = ["windows"]            # matches only Windows
  --when.platforms = ["linux", "freebsd"]   # matches Linux or and FreeBSD, but not macOS
  --when.platforms = ["unix"]               # matches anything in the Unix family (Linux, FreeBSD, macOS, etc.)
  ```