Don't install tools via snap... (was 'difft' not finding left or right).

[barries]

EDIT: to save you the read: I had installed difftastic via snap because Canonical "made" me... there was no apt package for it... and snap apparently did what snap apparently does, which is not integrate with the OS well.

Removing the snap and manually installing the difft binary fixed it.

---

Original question:

I must be missing something super obvious because if this broke it would be all over the forums, but I can't see why, with the config shown, jj v0.31 is passing left and right (without the $) instead of the filenames:

$ cat ~/.config/jj/config.toml
[user]
name = "barrie"
email = "barrie@email_elided.my"

[ui]
diff.tool = "difft"
$ jj diff --debug
2025-07-24T13:13:00.394273Z  INFO jj_cli::cli_util: debug logging enabled
2025-07-24T13:13:00.400124Z  INFO run_command:cmd_diff:request_pager: jj_cli::ui: spawning pager cmd=LESSCHARSET="utf-8" "less" "-FRX"
2025-07-24T13:13:00.401495Z  INFO run_command:cmd_diff: jj_cli::merge_tools::external: Invoking the external diff generator: cmd=cd "/tmp/jj-diff-uG7AV5" && "difft" "--color=always" "left" "right"
No such file: left
No such file: right
2025-07-24T13:13:00.441857Z  INFO run_command:cmd_diff: jj_cli::merge_tools::external: The external diff generator exited: cmd=cd "/tmp/jj-diff-uG7AV5" && "difft" "--color=always" "left" "right" exit_status=ExitStatus(unix_wait_status(512))
Warning: Tool exited with exit status: 2 (run with --debug to see the exact invocation)
$ jj --version
jj 0.31.0-7dadc13458fa001b0c359fe3138127fbe198cbd8

The same thing happens if I instead specify diff-formatter = ["difft", "--color=always", "$left", "$right"] .

The default operation works fine:

$ cat ~/.config/jj/config.toml
[user]
name = "barrie"
email = "barrie@email_elided.my"

[ui]
$ jj diff --debug
2025-07-24T13:21:44.123229Z  INFO jj_cli::cli_util: debug logging enabled
2025-07-24T13:21:44.129699Z  INFO run_command:cmd_diff:request_pager: jj_cli::ui: spawning pager cmd=LESSCHARSET="utf-8" "less" "-FRX"
Added regular file foo:
        1: hi

[yuja]

"left" and "right" are the directory names relative to "/tmp/jj-diff-uG7AV5". I don't know why these directories don't exist, though.

[barries]

Huh. This is on Ubuntu, which only has a snap for difftastic.

Removing that and downloading the difft binary into ~/bin worked. Sigh. F'in snaps.

[jasikpark]

I bet it's available on https://docs.brew.sh/Homebrew-on-Linux if you want yet another package manager 😅