YAML serialization can use new OmitDefaultsOrEmpty

[premun]

GitHubActionsDotNet/src/GitHubActionsDotNet/Serialization/YamlSerialization.cs

Line 20 in aa0f0a1

.ConfigureDefaultValuesHandling(DefaultValuesHandling.OmitDefaults) //New as of YamlDotNet 8.0.0: https://github.com/aaubry/YamlDotNet/wiki/Serialization.Serializer#configuredefaultvalueshandlingdefaultvalueshandling. This will not show null properties, e.g. "app-name: " will not display when the value is null, as the value is nullable

I was also serializing pipeline YAML and often had the resulting YAML full of empty arrays, things like:

steps: []

This is just an FYI that I added functionality there that also omits empty collections. Not sure if you are hitting this but might be of use to you too.

https://github.com/aaubry/YamlDotNet/releases/tag/v11.2.0
aaubry/YamlDotNet#608

[samsmithnz]

Do you have an example? Wouldn't this just skip steps from the output?

[premun]

Yes, it would. But at least in Azure Pipelines YAML you don't want to show some of these when empty.

I don't know how you deal with collections but in Sharpliner, I pre-initialize List<T> because C# 10 can give you an amazingly brief syntax using the implicit Add().

Say you have this:

class SomeClass
{
    List<string> SomeProperty { get; set; } = new();
}

then you can do this:

var x = new SomeClass
{
    SomeProperty = {
        "foo",
        "bar",
    }
}

However, this implicit Add only works if the List<T> property is non-null and initialized. Just calls Add on it.

Now, let's say you have pipeline triggers and want to use this - this means your Trigger property on the pipeline needs to be an initialized list but you don't really want your YAML to be always:

triggers: []

You only want triggers to be serialized when it's not empty.

Now, I don't know GH Actions much so I don't know if you have problems like this. Or you might just have null values for your Lists. Then you can disregard this :)

[premun]

Btw I reached out to you in a more reasonable manner on Teams but I guess you're off already (I didn't mean to ambush you here like this)

[samsmithnz]

I'm pretty sure that triggers: [] is valid, just ugly, as YAML is a superset of JSON. I think you can get around this by either not initializing the list, or using an array (with no items).