[API Proposal]: Allow nullable DateTimeOffset / TimeSpan for IMemoryCache.Set

[angelaki]

Background and motivation

Right now, wenn calling this overload, an actual value must be passed. It would be nice to allow nullable values here, since the target-property actually is.

API Proposal

public static TItem Set<TItem>(this IMemoryCache cache, object key, TItem value, DateTimeOffset? absoluteExpiration)
{
    using ICacheEntry entry = cache.CreateEntry(key);
    entry.AbsoluteExpiration = absoluteExpiration;
    entry.Value = value;

    return value;
}

API Usage

cache.Set(key, value, options?.absoluteExpirationRelativeToNow);

Alternative Designs

No response

Risks

No response

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[angelaki]

Here's the PR: #120972

[jozkee]

You are not missing much without these APIs, you can conditionally call each one and obtain the same result.

_ = options.AbsoluteExpirationRelativeToNow is { } expiration ?
    cache.Set("key", "value", expiration) :
    cache.Set("key", "value");

[angelaki]

Sure you can do this. Right now I'm working with an usual if. But since the target property is nullable anyway, why not make the parameter nullable?

[jozkee]

You wouldn't make the parameter nullable, you would have to add an overload to avoid a breaking change. CacheExtensions.Set currently has five overloads, and this proposal would introduce two additional ones.

Is the options variable you referenced in API Usage a MemoryCacheEntryOptions, or is it a different type?

If not, you could use the existing MemoryCacheEntryOptions overload instead of the conditional, though that would result in one extra allocation.

[angelaki]

Was thinking about using this overload already but saw that it internally calls setOptions with way more load involved than needed. Yeah, actually a no timer, but ... You know ... Btw, options is nullable, too. So I was thinking my PR / proposal might make sense?

And sure, binary breaking, yeah. But thats it. Might ship with a new .Net