meld is not working as expected

[nitrogenxx]

First and foremost, I would like to express my deepest appreciation and gratitude for the incredible project that you have developed. Your efforts have helped me overcome numerous challenges, and I cannot thank you enough for your hard work.

Currently, I am facing a minor issue related to the meld I'm sure is already addressed in it
I have thoroughly reviewed the project documentation which is incredibly well-written, of diff

~/.config/chezmoi/chezmoi.toml

[diff]
    command = "meld"
    args = ["--diff", "{{ .Destination }}", "{{ .Target }}"]

and i feel like this config is not working perfectly for me because when i run chezmoi diff it compares the config files form my $HOME directory to /tmp/chezmoi-diff*

so whenever any program make some changes in my $HOME directory I can compare the changes by meld using chezmoi diff but can't transfer the changes by clicking arrows ( => ) in the meld form my $HOME directory to chezmoi directory (which is ~/.local/share/chezmoi in my case)
in that case.. changes will be transfer to /tmp/chezmoi-diff* and not ~/.local/share/chezmoi/<some config file>

the solution I use is to use meld separately e.g. meld ~/.config/<some config file> ~/.local/share/chezmoi/<some config file> to transfer the changes form my $HOME directory to chezmoi directory

since I do not prefer to use chezmoi add <config file> for already managed files... because it transfers all changes form $HOME directory config to chezmoi directory where my need is to only transfer some few required changes and not all new changes

the "{{ .Destination }}" is pointing the correct location but the "{{ .Target }}" is not making changes in ~/.local/share/chezmoi/

I understand we can not point the "{{ .Target }}" to ~/.local/share/chezmoi/ because of different file prefix maybe that's why we are using /tmp/chezmoi-diff*

but then how we can use to transfer some changes of the config file form $HOME directory to chezmoi direcory

due to my limited understanding , I'm having difficulty comprehending how to implement these changes
Any assistance you can provide in resolving this issue would be greatly appreciated.
Thank you again for your hard work and dedication to this project. I look forward to hearing back from you .

[twpayne]

Thank you for the kind words!

but then how we can use to transfer some changes of the config file form $HOME directory to chezmoi direcory

For this you can use the merge command. This opens a three-way merge between the config file from the $HOME directory, the file in the chezmoi directory, and the target contents of the file.

You'll need to set merge.command configuration variable to meld to use meld, and you might want to tweak the order of arguments in the merge.args configuration variable.

[nitrogenxx]

~ ❯ cat ~/.local/share/chezmoi/.chezmoi.toml.tmpl

[merge]
    command = "meld"
    args = ["--diff", "{{ .Destination }}", "{{ .Source }}"]

~ ❯
~ ❯ chezmoi apply
chezmoi: warning: config file template has changed, run chezmoi init to regenerate config file
~ ❯
~ ❯ chezmoi init
chezmoi: template: chezmoi.toml:4:26: executing "chezmoi.toml" at <.Destination>: map has no entry for key "Destination"
~ ❯
~ ❯

[bradenhilton]

@nitrogenxx Does this variation work as expected?

[merge]
    command = "meld"
    args = ["--diff", {{ `{{ .Destination }}` }}, {{ `{{ .Source }}` }}]

@twpayne Do you have any theories on why this error seemingly only occurs for some users? I also ran into the same error a while ago while experimenting with #2424. I can only assume that the example in the docs works as expected for you (or whoever wrote that example). Is this assumption incorrect, and the example is actually wrong?

My understanding is that the arguments need to be literal strings and should not be parsed by the template engine while the config is being generated, as they will then be parsed when running the command. Is my understanding correct?

[nitrogenxx]

@bradenhilton

[merge]
    command = "meld"
    args = ["--diff", {{ `{{ .Destination }}` }}, {{ `{{ .Source }}` }}]

~ ❯ cat ~/.local/share/chezmoi/.chezmoi.toml.tmpl
 [merge]
     command = "meld"
     args = ["--diff", {{ `{{ .Destination }}` }}, {{ `{{ .Source }}` }}]

~ ❯ chezmoi init
chezmoi: /home/user/.local/share/chezmoi/.chezmoi.toml.tmpl: toml: invalid character at start of key: {
~ ❯

i have also tried
single quote args = ["--diff", {{ '{{ .Destination }}' }}, {{ '{{ .Source }}' }}]
double quote args = ["--diff", {{ "{{ .Destination }}" }}, {{ "{{ .Source }}" }}]

to make it a literal string but didn't work

[bradenhilton]

I think I missed some double quotes e.g.

"{{ `{{ .Destination }}` }}"

[nitrogenxx]

exactly i was just about to post it .. it worked 🤩

[merge]
    command = "meld"
    args = ["--diff", "{{ `{{ .Destination }}` }}", "{{ `{{ .Source }}` }}"]

@bradenhilton I'm so thankful of you from deep inside .. I truly appreciate your willingness to share your knowledge ✨✨🎉 🎉✨

[halostatue]

There are also a couple of other options here:

1. Change the delimiters so that you don't need to quote the values required for chezmoi (if you had ((: and :)) as delimiters, then you could simply do "{{ .Destination }}" inside the args array).
2. Use the quote or toToml filter: args = ["--diff", {{ "{{ .Destination }}" | toToml }}, {{ "{{ .Source }}" | quote }}]. Using toToml is better, but quote is equivalent here.

[bradenhilton]

I believe my initial understanding is correct.

The examples in the docs are correct, because they are assumed to be placed directly in chezmoi's config file (e.g. .config/chezmoi/chezmoi.$FORMAT). This is indeed what we need to end up with, a generated chezmoi config that contains template syntax for the relevant items.

The issue occurs when pasting them into a config template, because the examples themselves contain template syntax. The template engine tries to parse the syntax when the config is being generated, at which point the items don't exist, because they only exist when the requisite commands are run (diff, merge etc).

This is why they need to be escaped, or the delimiters for the config template need to be changed.

Given that we discourage editing chezmoi's config directly, I think we should address this in the docs somewhere. I'll think about the best way to tackle it.