Table of Contents

SHIFT008: Unsupported ShapeShift contract

Property Value
Rule ID SHIFT008
Category ShapeShift.Usage
Default severity Error
Enabled by default Yes
Code fix None

Cause

A type declares an extension-data contract that ShapeShift cannot build a converter for.

Rule description

ShapeShiftExtensionDataAttribute captures unknown properties so that a document round-trips without losing forward-compatible data. The contract has four requirements, each of which ShapeShift enforces at run time by throwing a ShapeShiftSerializationException while preparing the converter graph:

  1. A type may declare at most one extension-data member.
  2. The member's type must be exactly Dictionary<string, ShapeShiftValue>.
  3. The member must have a getter.
  4. A class that declares an extension-data member must be deserializable through a parameterless constructor.

This analyzer reports each violation on the attribute application.

How to fix violations

// Violation: wrong member type, and no parameterless constructor.
public class Extensible
{
    public Extensible(int required) { }

    [ShapeShiftExtensionData]
    public Dictionary<string, string> Extra { get; } = new();
}

// Fixed
[GenerateShape]
public partial class Extensible
{
    public int Required { get; set; }

    [ShapeShiftExtensionData]
    public Dictionary<string, ShapeShiftValue> Extra { get; } = new(StringComparer.Ordinal);
}

Structs are never reported for requirement 4, because a struct always has a parameterless constructor available to the deserializer.

When to suppress warnings

Do not suppress this diagnostic. The type cannot be serialized while the violation remains.

See also

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