Pure Context Mutation
Detects assignment operators inside property getter blocks or methods decorated with [Pure], indicating unexpected side effects.
Why this rule exists
Property getters and [Pure] methods are called by debuggers, serializers, and LINQ providers. Hidden side effects in them produce non-deterministic bugs that reproduce only under specific tooling.
Code example
+ public int Count
+ {
+ get { _accessCount++; return _items.Count; }
+ }+ public int Count => _items.Count;
+ public void RecordAccess() => _accessCount++;Configuration
Disable or adjust the severity of this rule in .gauntletci.json:
{
"rules": {
"GCI0036": { "enabled": true, "severity": "Block" }
}
}See Configuration for the full schema.
Related rules
Behavioral Change Detection
Detects removed logic (Warn), incompatible method signature changes (Block), backward-compatible extensions (Info), and cryptographic boundary changes (Block).
Concurrency and State Risk
Detects async void methods, blocking async calls (.Result, .Wait(), .GetAwaiter().GetResult()), lock(this), and Thread.Sleep in production code. Uses ForPatternScan to ignore matches inside // comments and string literals.
Discussed in
Why Code Review Misses Bugs
Code review catches style and obvious logic errors. It routinely misses behavioral drift, contract changes, and implicit assumptions.
A Formal Framework for Behavioral Change Risk
A structured taxonomy for behavioral, contract, concurrency, and side-effect risk in code diffs.
State of Behavioral Change Risk in .NET
A field report from 610 merged C# PRs across 61 repositories, with raw findings, high-confidence findings, and outlier disclosure.
Implemented in src/GauntletCI.Core/Rules/Implementations/GCI0036_*.cs.
Eric Cogen -- Founder, GauntletCI
Twenty years as a senior technical consultant building and modernizing enterprise platforms across .NET, AWS, serverless, microservices, and AI-driven systems.