How to change the diff program properly?

[k4leg]

~/.config/chezmoi/chezmoi.yaml file source:

diff:
  command: difft
  args:
    - --color
    - always
    - --missing-as-empty
    - --skip-unchanged

But this config doesn't use pager, and if I add next line to config (or if I use --pager option):

  pager: less

then pager show no diff, or partial diff if I use less -X instead of less.

Btw, diff program doesn't see scripts like run_after_blablabla.sh. If I specify echo instead of difft, then I won't see the scripts.

Additional info:

• difft is difftastic
• chezmoi 2.17.0

[twpayne]

The problem here is that difftastic includes its own pager and it does not seem possible to disable it. When difftastic's builtin pager is combined with less, the output is lost.

A work-around is to use cat instead of less as the diff pager, for example:

diff:
  command: difft
  args:
    - --color
    - always
    - --missing-as-empty
    - --skip-unchanged
  pager: cat

Btw, diff program doesn't see scripts like run_after_blablabla.sh. If I specify echo instead of difft, then I won't see the scripts.

Scripts are included in the diff output (unless you explicitly exclude them by setting diff.exclude). It's possible that difftastic does not display them however.

[k4leg]

difftastic doesn't include own pager:

• at least, I can not find any "pager" occurrence in source code
• if diff is large, difftastic doesn't use automatically any pager

difftastic works fine with --color always arguments and pipe to less -RF (enable color and exit if one page): difft --color always ./a ./b | less -RF.

Scripts are included in the diff output (unless you explicitly exclude them by setting diff.exclude). It's possible that difftastic does not display them however.

But why if I specify echo in diff.command, output doesn't include any scripts? How can it include scripts if arguments don't include scripts?

[twpayne]

It turns out that chezmoi's support for external diff programs is not complete, which is why you're seeing these issues. I've opened #2115 to track the problem.

[twpayne]

The latest version of chezmoi, v2.21.0, includes a number of fixes for external diff programs:

• Show scripts
• Show directory creation
• Support diff.include and diff.exclude
• Pass /dev/null instead of filename when file does not exist

The commit fixing these is db4da31.

[gdevenyi]

This appears to still be an issue, the following config does not invoke a pager

[diff]
    command = "difft"
    exclude = ["externals"]

Adding pager = "less" doesn't seem to change it.

[twpayne]

Could you give a minimal example that allows others to reproduce the problem?