# Error Modes Inventory - Marketplace Package Lifecycle
This document catalogs all error modes in the marketplace package project lifecycle that can be prevented through poka-yoke (type-level) design.
## 1. Invalid Lifecycle State Transitions
### Error: Running phases out of order
- **Example**: Running `deploy` before `build`, `test` before `build`
- **Current Detection**: Runtime validation (if any)
- **Impact**: Build failures, deployment of untested code
- **Prevention**: Type-level state machine using PhantomData markers
### Error: Skipping required phases
- **Example**: Running `deploy` without running `test` first
- **Current Detection**: None (implicit dependency)
- **Impact**: Deploying untested code
- **Prevention**: State machine enforces phase dependencies
### Error: Re-running phases in wrong order
- **Example**: Running `init` after `build` has already run
- **Current Detection**: None
- **Impact**: State corruption, unexpected behavior
- **Prevention**: State machine tracks completed phases
## 2. Invalid Package States
### Error: Installing unvalidated packages
- **Example**: Installing package without validation checks
- **Current Detection**: Runtime checks in `PackageBuilder::build()`
- **Impact**: Installing broken or malicious packages
- **Prevention**: Newtype wrapper `ValidatedPackage` - cannot install `UnvalidatedPackage`
### Error: Using packages without required metadata
- **Example**: Package missing title, description, or content_id
- **Current Detection**: Runtime validation in builder
- **Impact**: Incomplete package information, broken installations
- **Prevention**: Builder pattern ensures required fields before validation
### Error: Installing packages with invalid dependencies
- **Example**: Package depends on non-existent or incompatible packages
- **Current Detection**: Runtime during installation
- **Impact**: Installation failures, dependency conflicts
- **Prevention**: Validation step checks dependencies before creating `ValidatedPackage`
## 3. Invalid Phase Configuration
### Error: Phases with no commands
- **Example**: Phase defined but has empty `commands` array
- **Current Detection**: Runtime check in `run_phase` (returns Ok with warning)
- **Impact**: Silent failures, phases that do nothing
- **Prevention**: `PhaseBuilder` requires at least one command before building `ValidatedPhase`
### Error: Invalid hook dependencies
- **Example**: Hook references non-existent phase
- **Current Detection**: Runtime error when hook executes
- **Impact**: Hook failures, broken lifecycle
- **Prevention**: Hook validation checks all referenced phases exist
### Error: Circular hook dependencies
- **Example**: `before_build` includes `build`, which includes `before_build`
- **Current Detection**: Runtime recursion detection (`HookRecursion` error)
- **Impact**: Infinite loops, stack overflow
- **Prevention**: Compile-time DAG validation where possible, runtime cycle detection
## 4. Invalid State Persistence
### Error: Corrupted state files
- **Example**: JSON parse errors, invalid state structure
- **Current Detection**: Runtime parsing errors
- **Impact**: Lost state, cannot resume lifecycle
- **Prevention**: `ValidatedLifecycleState` wrapper ensures state passes validation before use
### Error: Invalid state transitions in persisted state
- **Example**: State shows `deploy` completed but `build` never ran
- **Current Detection**: None (state is trusted)
- **Impact**: Inconsistent state, incorrect caching
- **Prevention**: State validation checks phase history consistency
### Error: Cache keys for non-existent phases
- **Example**: Cache key references phase that was removed from config
- **Current Detection**: None
- **Impact**: Stale cache entries, incorrect cache hits
- **Prevention**: State validation checks cache keys reference valid phases
## 5. Invalid Hook Dependencies
### Error: Circular hook dependencies
- **Example**: `before_a` includes `b`, `before_b` includes `a`
- **Current Detection**: Runtime recursion detection
- **Impact**: Infinite loops, stack overflow
- **Prevention**: Compile-time validation for static hooks, runtime detection for dynamic
### Error: Hooks referencing non-existent phases
- **Example**: `before_build` includes `validate` but `validate` phase doesn't exist
- **Current Detection**: Runtime error when hook executes
- **Impact**: Hook failures, broken lifecycle
- **Prevention**: Hook validation checks all referenced phases exist in config
### Error: Self-referential hooks
- **Example**: `before_build` includes `build`
- **Current Detection**: Runtime recursion detection
- **Impact**: Infinite loops
- **Prevention**: Hook validation prevents self-references
## 6. Invalid Context Usage
### Error: Using context after lifecycle completion
- **Example**: Running phases after pipeline completed
- **Current Detection**: None
- **Impact**: State corruption, unexpected behavior
- **Prevention**: State machine tracks lifecycle completion
### Error: Parallel execution conflicts
- **Example**: Multiple threads modifying same state simultaneously
- **Current Detection**: Mutex poisoning (rare)
- **Impact**: State corruption, data races
- **Prevention**: Thread-safe state management (already implemented)
## Summary
All identified error modes can be prevented through:
1. **Type-level state machine** - Prevents invalid phase transitions
2. **Validated types** - Prevents using unvalidated data
3. **Builder patterns** - Ensures required fields before construction
4. **State validation** - Prevents using corrupted state
5. **Hook validation** - Prevents circular and invalid dependencies
These poka-yoke mechanisms make entire classes of errors impossible at compile time.