Roslyn Analyzers & Code Quality Rules

Granit.Analyzers provides Roslyn analyzers that enforce Granit conventions at compile time, with immediate feedback in the IDE (red squiggles). They complement runtime checks and architecture tests with zero-cost static analysis.

Installation

dotnet add package Granit.Analyzers

The package ships both analyzers and code fix providers. No additional configuration is required — rules activate automatically based on the project’s dependencies.

Rules

Architecture

Rules enforcing modular monolith boundaries.

Rule	Severity	CodeFix	Description
GRMOD001	Error	Yes	Cross-module reference to internal type — use Contracts

GRMOD001 — Cross-module reference detection

Detects when code in one module references internal types from another module instead of using the .Contracts namespace.

Applies to: projects using the *.Modules.{ModuleName} namespace convention.

Opt-in: the analyzer only activates when *.Modules.* namespaces are present in the compilation. Projects without this convention pay zero runtime cost.

Allowed references:

• Types in *.Modules.{Module}.Contracts and sub-namespaces
• Types within the same module
• Types outside *.Modules.* (framework, BCL, shared libraries)

Forbidden references:

• Types in *.Modules.{OtherModule}.Domain
• Types in *.Modules.{OtherModule}.Handlers
• Types in *.Modules.{OtherModule}.Services
• Any non-Contracts namespace of another module

CodeFix: if a type with the same name exists in the target module’s .Contracts namespace, the code fix suggests replacing the using directive.

Bad

// ❌ GRMOD001: InventoryService from module Inventory cannot be
//    referenced from module Orders
using MyApp.Modules.Inventory.Services;

namespace MyApp.Modules.Orders.Handlers;

public class OrderHandler(InventoryService inventory) { }

Good

// ✅ Use the Contracts namespace
using MyApp.Modules.Inventory.Contracts;

namespace MyApp.Modules.Orders.Handlers;

public class OrderHandler(IInventoryReader inventory) { }

Migrations

Rules enforcing zero-downtime migration patterns (expand/migrate/contract).

Rule	Severity	CodeFix	Description
GRMIGA001	Error	—	DropColumn requires a Contract-phase annotation
GRMIGA002	Error	—	RenameColumn is not zero-downtime safe
GRMIGA003	Warning	—	AddColumn NOT NULL without default risks table lock
GRMIGA004	Warning	—	AlterColumn type change requires Contract-phase annotation

Security

Rules enforcing testability, secret management, and GDPR compliance.

Rule	Severity	CodeFix	Description
GRSEC001	Warning	Yes	Avoid DateTime.Now/UtcNow — use IClock
GRSEC002	Warning	Yes	Avoid Guid.NewGuid() — use IGuidGenerator
GRSEC003	Error	—	Potential hardcoded secret detected
GRSEC004	Warning	Yes	Avoid direct IResponseCookies — use IGranitCookieManager
GRSEC010	Error	—	PII-indicative name used as metric tag key
GRSEC011	Error	—	PII-indicative placeholder in LoggerMessage template

GRSEC010 — PII in metric tag keys

Detects TagList initializers where the key (first string literal in each { "key", value } pair) matches a PII-indicative pattern: email, phone, ipAddress, username, ssn, passport, token, etc.

PII as metric tag keys causes both a GDPR violation (PII in telemetry backends) and a cardinality explosion (unbounded memory, high cost in Prometheus/Grafana).

Bad

// ❌ GRSEC010: Tag key 'email' matches a PII pattern
_counter.Add(1, new TagList
{
    { "email", user.Email },
    { "tenant_id", tenantId },
});

Good

// ✅ Use bounded, low-cardinality identifiers
_counter.Add(1, new TagList
{
    { "user_id", userId },
    { "tenant_id", tenantId },
});

GRSEC011 — PII in LoggerMessage placeholders

Detects [LoggerMessage] templates containing placeholders whose names match PII-indicative patterns. Supports both named (Message = "...") and positional ([LoggerMessage(id, Level, "...")]) constructor forms. Escaped braces ({{/}}) are correctly skipped.

PII in structured logs violates GDPR Art. 5 (data minimization) and exposes personal data to log aggregation systems (ELK, Loki, Application Insights).

Bad

// ❌ GRSEC011: PII placeholder {Email}
[LoggerMessage(Level = LogLevel.Information,
    Message = "User {Email} logged in from {IpAddress}")]
private static partial void LogUserLogin(
    ILogger logger, string email, string ipAddress);

Good

// ✅ Log identifiers, not PII
[LoggerMessage(Level = LogLevel.Information,
    Message = "User {UserId} logged in")]
private static partial void LogUserLogin(
    ILogger logger, string userId);

Entity Framework

Rules enforcing async-first EF Core patterns.

Rule	Severity	CodeFix	Description
GREF001	Warning	Yes	Use SaveChangesAsync() instead of SaveChanges()

API

Rules enforcing Minimal API conventions and RFC 7807 compliance.

Rule	Severity	CodeFix	Description
GRAPI001	Warning	Yes	Use TypedResults instead of Results for OpenAPI
GRAPI002	Warning	Yes	Use TypedResults.Problem() instead of BadRequest (RFC 7807)

Suppressing rules

To suppress a specific rule for a file or project:

// File-level suppression
#pragma warning disable GRMOD001

<!-- Project-level suppression in .csproj -->
<PropertyGroup>
  <NoWarn>$(NoWarn);GRMOD001</NoWarn>
</PropertyGroup>

Caution

Architecture rules (GRMOD) are also enforced by NetArchTest at CI time. Suppressing the analyzer does not bypass the CI gate.