Adding sortable tag field support & UNF support

[slorello89]

Adding the ability to add sorted tag fields in indices per #1838

Note: When serializing the arguments RediSearch cares about the order of the separator and sortable arguments, hence after calling base.SerializeRedisArgs, if the index is sortable and removes the sortable flag, and then adds it back after the separator flag is added.

[dcoopertd]

While you are in there, could support for the new UNF be added as well? RediSearch/RediSearch#2188

[AvitalFineRedis]

@dcoopertd https://github.com/slorello89/StackExchange.Redis/pull/1

[mgravell]

The main problem I can see here is the breaking change on TextField's ctor and the AddSortableTextField method which is going to cause MissingMethodException on anything that takes a transient dependency (i.e. not rebuilt explicitly). We usually try hard to avoid hard breaks, with the preferred method being: to add overloads rather than optional args.

For example:

- public TextField(string name, double weight = 1.0, bool sortable = false, bool noStem = false, bool noIndex = false)
- : base(name, FieldType.FullText, sortable, noIndex)
+ public TextField(string name, double weight = 1.0, bool sortable = false, bool noStem = false, bool noIndex = false, bool unf = false)
+ : base(name, FieldType.FullText, sortable, noIndex, unf)

could be achieved instead via:

public TextField(string name, double weight, bool sortable, bool noStem, bool noIndex)
  : this(name, weight, sortable, noStem, noIndex, false) {}
public TextField(string name, double weight = 1.0, bool sortable = false, bool noStem = false, bool noIndex = false, bool unf = false)

• by adding the overload, we don't break existing code (noting that adding/removing default parameter values does not cause a MissingMethodException)
• by removing the parameter defaults, we ensure that most rebuilt new code goes to the new method, and doesn't pay any indirection overhead

Likewise:

- public Schema AddSortableTextField(string name, double weight = 1.0)
+ public Schema AddSortableTextField(string name, double weight = 1.0, bool unf = false)

could be

public Schema AddSortableTextField(string name, double weight)
  => AddSortableTextField(name, weight, false);
public Schema AddSortableTextField(string name, double weight = 1.0, bool unf = false)

[mgravell]

If we can fix ^^^, and add something to releasenotes.md, we should be set?

[mgravell]

oh: additional thought: what is unf? the fact that I need to ask suggests that it needs to be clearer; perhaps unNormalizedForm would be clearer than unf?

I also wonder whether we're getting into the territory where a [Flags] enum might be a better choice than a myriad of bool values?

[mgravell]

Lgtm, ta

[slorello89]

The main problem I can see here is the breaking change on TextField's ctor and the AddSortableTextField method which is going to cause MissingMethodException on anything that takes a transient dependency (i.e. not rebuilt explicitly). We usually try hard to avoid hard breaks, with the preferred method being: to add overloads rather than optional args.

TIL -> thanks for pointing that out.