REslava.Result.Flow — Native Companion Package

For projects using REslava.Result, the companion package REslava.Result.Flow adds two capabilities not possible in the library-agnostic package:

• Typed error edges — scans each step's method body for new XxxError(...) constructions where XxxError implements IError; renders -->|DatabaseError| FAIL edges instead of generic fail arrows
• IOperation chain walker — uses Roslyn's semantic model at the IInvocationOperation level, which makes the pipeline entry-point call (e.g. CreateUser()) visible as its own node

dotnet add package REslava.Result.Flow

Add using REslava.Result.Flow; — the attribute type is injected automatically by the generator, no separate assembly reference needed.

/*
```mermaid
flowchart LR
    N0_CreateUser["CreateUser<br/>User"]:::operation
    N0_CreateUser --> N1_EnsureAsync
    N1_EnsureAsync["EnsureAsync ⚡<br/>User"]:::gatekeeper
    N1_EnsureAsync -->|pass| N2_BindAsync
    N1_EnsureAsync -->|ValidationError| FAIL
    N2_BindAsync["BindAsync ⚡<br/>User"]:::transform
    N2_BindAsync -->|ok| N3_MapAsync
    N2_BindAsync -->|DatabaseError| FAIL
    N3_MapAsync["MapAsync ⚡<br/>User → UserDto"]:::transform
    FAIL([fail]):::failure
    classDef gatekeeper fill:#e3e9fa,color:#3f5c9a
    classDef transform fill:#e3f0e8,color:#2f7a5c
    classDef failure fill:#f8e3e3,color:#b13e3e
    classDef operation fill:#e8f4f0,color:#1c7e6f
```*/
[ResultFlow]
public Task<Result<UserDto>> RegisterAsync(RegisterCommand cmd) =>
    CreateUser(cmd)
        .EnsureAsync(IsEmailValid, u => new ValidationError("email", "invalid"))
        .BindAsync(SaveUser)
        .MapAsync(ToUserDto);

Paste the comment into mermaid.live — CreateUser becomes the pipeline root, ValidationError and DatabaseError appear as typed failure edges on their respective steps. Here you can see the resulting diagram:

flowchart LR
    N0_CreateUser["CreateUser<br/>User"]:::operation
    N0_CreateUser --> N1_EnsureAsync
    N1_EnsureAsync["EnsureAsync ⚡<br/>User"]:::gatekeeper
    N1_EnsureAsync -->|pass| N2_BindAsync
    N1_EnsureAsync -->|ValidationError| FAIL
    N2_BindAsync["BindAsync ⚡<br/>User"]:::transform
    N2_BindAsync -->|ok| N3_MapAsync
    N2_BindAsync -->|DatabaseError| FAIL
    N3_MapAsync["MapAsync ⚡<br/>User → UserDto"]:::transform
    FAIL([fail]):::failure
    classDef gatekeeper fill:#e3e9fa,color:#3f5c9a
    classDef transform fill:#e3f0e8,color:#2f7a5c
    classDef failure fill:#f8e3e3,color:#b13e3e
    classDef operation fill:#e8f4f0,color:#1c7e6f

Error scanning is best-effort — only scans methods in the same compilation; errors created but not returned may appear as false positives; helper methods are not recursively followed.

	REslava.ResultFlow	REslava.Result.Flow
Works with any library	✅	❌ REslava.Result only
⚡ async annotation	✅	✅
Success type travel	✅ (first generic arg)	✅ (via IResultBase)
Typed error edges	❌	✅ (IError body scan)
Entry-point call as node	❌	✅ (IOperation walk)

Which package should I use? Using REslava.Result? → use REslava.Result.Flow. It produces richer diagrams with typed error edges and deeper type travel.

Feature Comparison

Using FluentResults, ErrorOr, LanguageExt, or any other library? → use REslava.ResultFlow. Zero configuration needed for Bind and Map (both are in the built-in convention dictionary).

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