Munchausen Dev Log: Build() Stops Lying — Compiler Achieves Single-Pass, Recursion-Safe Plan Validation in C#

Dev Log: The milestone where Build() stops lying

Ernesto Herrera Salinas’ Munchausen NuGet package reached Milestone 5 (M5), where the Build() method finally works. After three milestones of throwing NotImplementedException, it now compiles a complete, frozen plan and collects all five diagnostic failure codes before throwing.

Why This Matters

Technical reality demands that error handling be a first-class feature, not an afterthought. Munchausen’s new approach collects all failures in a single exception (LIE001-LIE005) instead of forcing developers to discover them one at a time—a pattern that makes failed definitions easier to fix and reduces debugging cycles by an order of magnitude.

Key Insights

• Recursive-type graph solved via visited set and worklist: Employee’s Manager being Employee now completes in single pass with friendly LIE009 Info note (M5, 2026).
• Diagnostic code registry with conformance test keeps expected errors in sync: LIE001 for nested path illegal targets, LIE002 for With/Ignore contradiction on same member (M5, 2026).
• Placeholder delegate for generators deferred to M7: ‘bound in M7’ throw ensures milestone boundary without pretending leaves are finished (M5, 2026).
• ‘dotnet format’ tooling mystery broke for public API file generation; hand-wrote exception-type entries instead (M5, 2026).

Practical Applications

• Use case: Lie.Define().Build() returning immutable LieDefinition—complete frozen plan with constructor choice and member value sources.
• Pitfall: Two-phase ‘allocate empty shells’ approach replaced by simpler visited set + worklist pattern; avoids infinite recursion in type graphs.
• Use case: Diagnostic codes LIE001-LIE005 provide stable failure labels; conformance test prevents accidental erosion of error message quality.

References:

• From internal analysis