Chezmoi Merging

Published on 2020-10-03
Edited on 2020-10-04

Categories: tech
Tags: 100DaysToOffload

Adjusting chezmoi to my workflow

Today, I’ve been adjusting chezmoi to match my workflow for editing dotfiles.

You may be interested to read my previous post where I go over how to setup and use chezmoi: Dotfiles management using chezmoi - How I Use Linux Desktop at Work Part5

The workflow I’m seeking:

1. edit the files in place the same way I edit any files. I don’t want to use chezmoi edit on some files, and open files directly in vim or Emacs for other files.
2. run chezmoi merge on all files changed
3. configure chezmoi to automatically commit and push

Right now, I need to remember not to run chezmoi apply to prevent loosing changes.

Issues with default chezmoi behavior

Implementing my workflow is not easily supported by chezmoi:

1. chezmoi does not support changing the order of files specified when calling the mergetool. kdiff3 merge tool requires a different order to setup base, local, and remote files.
2. there are no chezmoi merge –all commands to merge all files that changed

implementing the workflow

setting up kdiff3 as my mergetool

chezmoi has an option to specify the mergetool:

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[merge]
  command = kdiff3
  args = [ "-m" ]

This has the first issue listed above: kdiff3 is called with files in the wrong order

Here is my step process to solve this problem

step 1: lets create our own kdiff wrapper script

I could have contributed a change to chezmoi to get this working (and I may will), but I need a solution now.

So I choose to create a script in ~/.local/bin/ called kdiff3merge:

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#!/bin/sh
local="$1"
chezmoi="$2"
base="$3"

kdiff3 -m "$base" "$chezmoi" "$local" -o "$chezmoi"

and modify my ~/.config/chezomi/chezmoi.toml:

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[merge]
  command = "kdiff3merge"

note: ~/.local/bin is in my path

Now, when calling chezmoi merge ~/.zshenv I get a good result:

Now I just accept the automatically merged changes by saving the changes and closing kdiff3.

One issue I’ve found with this is it creates a dot_zshenv.orig file corresponding to the chezmoi controlled file before the change was applied. I don’t need these since I use version control.

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#!/bin/sh
local="$1"
chezmoi="$2"
base="$3"

kdiff3 -m "$base" "$chezmoi" "$local" -o "$chezmoi"

test -f "$chezmoi.orig" && rm -f "$chezmoi.orig"

Now orig files are gone.

This is what I needed to fix the first chezmoi limitation I found.

Run chezmoi merge on all files changed

Chezmoi has couple of commands that gives information about changes:

1. chezmoi diff
2. chezmoi apply -n -v

Both commands are actually too verbose. I could not find a way to just print the list of files to bring in.

Obviously, I ended up creating an alias that does this:

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alias cmm="chezmoi diff -f git | grep -- ^--- | sed -e 's/^--- a\///' | xargs -r chezmoi merge"

If we deconstruct this command:

1. chezmoi diff -f git: prints all changed files, with their changes
2. grep – ^—: this one filter in lines which starts with —. the – prefix is to tell grep the — are not part of the “-” options (like -V)
3. sed -e ’s/^— a\///’: this command remove from lines found on step 2, the “— a/” prefix found. at this point, we end up with file path/names only
4. xargs -r chezmoi merge: runs chezmoi merge on all files found, or run nothing if no files found

Problem solved. I regularly run the cmm alias to bring my changes in chezmoi.

Commit and push my changes

chezmoi supports that off the shelf and can be enabled with the chezmoi.toml:

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[sourceVCS]
  autoCommit = true
  autoPush = true

[merge]
  command = "kdiff3merge"

Conclusion and thoughts

CLI tools offer quick ways to extend or customize to fit your habits.

That being said, my scripts may break at any chezmoi release update.

I just cloned the chezmoi repo, and looking to contribute more permanent changes to chezmoi diff and chezmoi merge commands. This will be a good opportunity to learn go.

This is day 16 of my #100DaysToOffload. You can read more about the challenge here: https://100daystooffload.com.

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