Role of null values in (de)serialized histograms

[taqtiqa-mark]

Ambiguity Report

Context, creating a Rust implementation. To keep the exercise finite/do-able within the resource and time constraints available, I intend that a 1.0 release:

• Will not support any serialization version prior to the release date.
• Will not support any serialized histogram produced by an implementation that could serialize a null value.

While I haven't finished, right now it isn't clear to me what the role of null values is in a DynaHist histogram.

Related to this, there is no explicit statement(s) about what data types are supported in a DynaHist.
As best I can tell the supported data types are Java's Int, Long and IEEE 754 - excluding NaN, and the infinities.

Expected Behavior

In DynaHist null is never a (de)serialized value.

Current Behavior

Current code comments in src/dynahist/src/main/java/com/dynatrace/dynahist/serialization/SerializationReader.java:

Implementations should never return {@code null} except for the case {@code null} was really the serialized value.

We're curious to known the context for expecting null in a (de)serialized histogram.

Possible Solution

Document a requirement that implementation MUST ensure that null is never a serialized value.

Detailed Description

Likely a update to the (de)serialization comments:

• README.md
• SerializationReader.java
• SerializayionWriter.java
• Test case

Possible Implementation

Happy to draft a PR but the maintainers will likely find it quicker to add any such details themselves?

[taqtiqa-mark]

Closing. Null values aren't supported.