Inconsistent ModelPart.GetProperties

[miguelmaso]

Description

I've observed the following discrepancy in the ModelPart interface:

• From the c++ interface, ModelPart.GetProperties(id) returns the property with the corresponding id from the mesh 0 (default value)
• From the python interface, ModelPart.GetProperties(id) returns all the properties from the mesh with the corresponding id.

[loumalouomega]

I opened a discussion about this in the past, and I don't remember why we keep it (I think because it would break to much code)

[miguelmaso]

Recap

	item	container
Value	Node	Nodes
	Element	Elements
	Condition	Conditions
	Properties	Properties
Methods	CreateNew(item) Has(item) Get(item) Add(item) Remove(item)	(container) Set(container)

• Properties means the item and also the container.
• The Python interface adds Get(container). In general, this is not a problem, but it conflicts in the case of the properties. Consequently, there are multiple definitions of GetProperties in Python, returning the container or the item.
• Furthermore, the properties Id may be confused with the mesh Id (legacy).

My proposal

1. Remove the mesh Id from the python interface ([Core] [Properties] Remove MeshIndex from GetProperties #9774). This is a behavior change.

- GetProperties(mesh_id) -> Container
+ GetProperties(prop_id) -> Item

2. Remove the GetProperties() (container), which can be confused with GetProperties(id) (item). This is an API breaker.

[miguelmaso]

NOTE: I'm not sure about the proposal 2 and I would like to hear opinions.

Pros:

• Avoid confusion between properties item and properties container
• Easy to replace

Cons:

• There is a GetNodes etc, but not GetProperties (container)
• ~1k of deprecation warnings

[miguelmaso]

In @KratosMultiphysics/implementation-committee we prefer only to remove the mesh id (option 1)