New release 1.18 is now returning an error when loading "expected a map, got 'ptr'"

mrz1836 commented 7 months ago

Preflight Checklist

[X] I have searched the issue tracker for an issue that matches the one I want to file, without success.
[X] I am not looking for support or already pursued the available support channels without success.
[X] I have checked the troubleshooting guide for my problem, without success.

Viper Version

1.18.0

Go Version

1.20

Config Source

Environment variables, Files

Format

JSON

Repl.it link

No response

Code reproducing the issue

Here is a snippet for how we are loading our config from JSON files.

We have a very large amount of configuration settings which is a series of structs or nested structs.

/*
// Set a replacer for replacing double underscore with nested period
    replacer := strings.NewReplacer(".", "__")
    viper.SetEnvKeyReplacer(replacer)

    // Set the prefix
    viper.SetEnvPrefix(EnvironmentPrefix)

    // Use env vars
    viper.AutomaticEnv()

    // Get the embedded envs directory
    var files []fs.DirEntry
    if files, err = envDir.ReadDir("envs"); err != nil {
        return nil, err
    }

    // Set the configuration type
    viper.SetConfigType("json")

    // Loop through the files
    for _, file := range files {
        if file.Name() == environment+".json" {
            var f fs.File
            if f, err = envDir.Open("envs/" + file.Name()); err != nil {
                return nil, err
            }
            if err = viper.ReadConfig(f); err != nil {
                return nil, err
            }
        }
    }

    // Unmarshal into values struct
    if err = viper.Unmarshal(&_appConfig); err != nil {
        err = fmt.Errorf("error loading viper values: %w", err)
        logger.Data(2, logger.ERROR, err.Error())
        return nil, err
    }
*/

Expected Behavior

Our project has been using viper for the past year with no issues. Just installed the new version and now we cannot load our config.

Actual Behavior

Received unexpected error: error loading viper values: '' expected a map, got 'ptr'

Steps To Reproduce

Working on steps to reproduce since I cannot copy our private code into this issue tracker.

Additional Information

For now we will be targeting the previous release of Viper.

Is there something that changed in this new version that would should be aware of?

github-actions[bot] commented 7 months ago

👋 Thanks for reporting!

A maintainer will take a look at your issue shortly. 👀

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mrz1836 commented 7 months ago

I think I figured it out:

Changed my config to be a value instead of a pointer:

_appConfig := Config{
AWS:       &AWSConfig{},
Datastore: &DatastoreConfig{},
Email:     &EmailConfig{},
Services:  &Services{},
}

vs my old way:

_appConfig := &Config{
AWS:       &AWSConfig{},
Datastore: &DatastoreConfig{},
Email:     &EmailConfig{},
Services:  &Services{},
}

Now you unmarshal into a pointer of a value

// Unmarshal into values struct
    if err = viper.Unmarshal(&_appConfig); err != nil {
        err = fmt.Errorf("error loading viper values: %w", err)
        logger.Data(2, logger.ERROR, err.Error())
        return nil, err
    }

spf13 / viper