toml.Unmarshal returning empty slice when using struct

[cyrus01337]

I have the below code that represents parsing a TOML file's contents. For some reason this doesn't seem to work as shown in the examples, what am I missing exactly?

type UnmappedConfiguration struct {
    dotfiles_repository string
    project_patterns    []string
}

type MappedConfiguration struct {
    DotfilesRepository string
    ProjectPatterns    []string
}

func parseConfiguration() (configurationPointer *Configuration, exception error) {
	var unmappedConfiguration UnmappedConfiguration
        // emulates os.ReadFile post error-handling
	doc := `
        dotfiles_repository = "https://github.com/cyrus01337/dotfiles"
        project_patterns = ["$HOME/Projects/*/*", "$HOME/Playground/", "$ZDOTDIR/"]
        test = "test"
    `
	exception = toml.Unmarshal([]byte(doc), &unmappedConfiguration)

	if exception != nil {
		return nil, exception
	}

	fmt.Println(unmappedConfiguration) // { []}

	return &configurationPointer, nil
}

I have seen #873 though as I'm new to this library, I may be mistaken in thinking this isn't related to the library itself and is purely a user issue. Do correct me if I'm wrong however as I may not know better in this situation.

[pelletier]

Hi! go-toml only unmarshals public fields of structs (same behavior as encoding/json). You can use the toml tag to specify the name of the toml key if it differs from the fields' name. For example, I think the following does what you want:

https://go.dev/play/p/LoLPP1BZygY

package main

import (
	"fmt"

	"github.com/pelletier/go-toml/v2"
)

type MappedConfiguration struct {
	DotfilesRepository string   `toml:"dotfiles_repository"`
	ProjectPatterns    []string `toml:"project_patterns"`
}

func main() {
	var unmappedConfiguration MappedConfiguration
	doc := `
        dotfiles_repository = "https://github.com/cyrus01337/dotfiles"
        project_patterns = ["$HOME/Projects/*/*", "$HOME/Playground/", "$ZDOTDIR/"]
        test = "test"
    `

	exception := toml.Unmarshal([]byte(doc), &unmappedConfiguration)

	if exception != nil {
		panic(exception)
	}

	fmt.Println(unmappedConfiguration) // {https://github.com/cyrus01337/dotfiles [$HOME/Projects/*/* $HOME/Playground/ $ZDOTDIR/]}

}

[cyrus01337]

Did not know you could map properties in this way.

This worked and also cut down some boilerplate as a plus, thank you so much! I'm loving this library so far. :)