feat: Command method to return the equivalent `git` command string

[nikclayton]

Description

I'd like a method on each *Command that either returns a string or passes the string to a caller-provided function.

The string should be the equivalent git command line invocation for the command.

Motivation

I'm writing automation, and I want to log the git operations the automation is performing. A natural way to do this is to log the operations as the equivalent git commands.

1. The people reviewing the logs are familiar with git.
2. In case of a problem it makes it easy to manually walk through the same operations the automation performed by copy/pasting the command.

Right now I'm doing this in Kotlin, and can do this with a lot of extension functions and some reflection to get at private properties. For example, for AddCommand:

inline fun <reified T : Any, R> T.getPrivateProperty(name: String): R? {
    val field = this::class.java.getDeclaredField(name)
    field.isAccessible = true
    @Suppress("UNCHECKED_CAST")
    return field.get(this) as R?
}

fun AddCommand.info(t: Terminal): AddCommand {
    val update = if (getPrivateProperty<AddCommand, Boolean>("update") == true) " --update" else ""
    val filePatterns = getPrivateProperty<AddCommand, Collection<String>>("filepatterns")
        ?.joinToString(" ")

    t.info("- git add$update $filePatterns")
    return this
}

and then the call site looks like this:

val t = Terminal()

git.add()
    .setUpdate(false)
    .addFilePattern("foo")
    .info(t)
    .call()

which (for my use case) prints

- git add foo

to the terminal when this runs. This is specific to my use case and isn't very general, which is why I suggest the JGit equivalent (if implemented) should take a caller-provided function which receives the command string and decides what to do with it.

Alternatives considered

No response

Additional context

No response

[msohn]

This might be rather straight-forward to implement on JGit commands in the org.eclipse.jgit.api package which closely follow corresponding commands in git CLI. So far JGit does not build such git command strings, it is not using C git under the hood but implementing git functionality in pure Java.

For lower level APIs that's probably a lot more work since they don't necessarily follow git CLI command syntax.