📘 Technical Design 010 — DI Bootstrapping & Early Initialization¶

Field	Value
ID	TD-010
Title	DI Bootstrapping & Early Initialization
Status	Completed
Owner	Contributors
Audience	Contributors, maintainers, DI system users
Created	2025-10-02
Last Updated	2025-10-03
Reviewers	TBD
Approvers	TBD
Tracking	Phase 2 of DI Roadmap
Related	001-dependency-injection-roadmap.md

🧭 1. Summary¶

This technical design implements Phase 2 of the DI roadmap by adding automatic bootstrapping with early initialization support to the DiContainer. The design introduces dependency cycle detection, fail-fast validation, and thread-safe singleton resolution during the bootstrap process.

At a glance:

Automatic bootstrapping triggered on first resolve call
Manual bootstrap capability with container.bootstrap()
Dependency cycle detection with clear error reporting
Early singleton resolution and validation
Thread-safe bootstrapping process with idempotent behavior

📚 2. Context and Problem Statement¶

The Phase 1 container provides registration and resolution but lacks initialization orchestration and dependency validation:

Current Limitations¶

No Dependency Validation - Circular dependencies discovered at runtime during resolution
Late Error Detection - Dependency issues only surface when specific services are resolved
No Initialization Control - No way to eagerly initialize critical singletons
Missing Validation - No pre-runtime validation of dependency graph integrity

2.1 Goals¶

Automatic Bootstrapping - Trigger bootstrap process on first resolve call
Dependency Cycle Detection - Identify and report circular dependencies before runtime
Early Singleton Resolution - Resolve all registered singletons during bootstrap
Fail-Fast Validation - Validate dependency graph integrity at bootstrap time
Thread-Safe Operations - Ensure bootstrap process is thread-safe and idempotent

2.2 Non-Goals (Out of Scope)¶

Named registrations or qualifiers (future consideration)
Advanced lifecycle scopes beyond singleton/transient (Phase 4+)
Configuration binding and property injection (Phase 4)
Module scanning and auto-discovery (Phase 5)

2.3 Assumptions and Constraints¶

Phase 1 DiContainer implementation is complete and available
Dependency tracking infrastructure from Phase 1 is functional
Bootstrap process should be optional and manual override-able
Thread safety without significant performance degradation

🧩 3. Design Overview¶

The bootstrap system transforms the Phase 1 container into a self-validating, dependency-aware container with automatic initialization orchestration. The design centers around atomic operations, container status management, and * *graph-based dependency analysis**.

3.1 Core Design Principles¶

🔄 Container Status Lifecycle: Three-state management (READY/PENDING/FAILED) with clear transitions:

READY: Empty container or successfully bootstrapped
PENDING: Services registered, bootstrap required
FAILED: Bootstrap failed, recovery needed

⚛️ Atomic Bootstrap Operations: All-or-nothing bootstrap with complete state reversion on failure.

📊 Graph-Based Analysis: Leverage loryth.common.collections.graph for both cycle detection and dependency ordering.

🔍 Reflection-Driven Dependencies: Fresh dependency analysis during bootstrap using reflection system.

3.2 Bootstrap Flow Architecture¶

graph TD
    A[Container Created<br/>Status: READY] --> B[Service Registration]
    B --> C[Status: PENDING]
    C --> D[First Resolve Call]
    D --> E{Status Check}
    E -->|PENDING| F[Trigger Bootstrap]
    E -->|READY| G[Direct Resolution]
    E -->|FAILED| H[❌ Bootstrap Error]

F --> I[Build Dependency Graph<br/>AdjacencyListGraph]
I --> J[Topological Sort<br/>Cycle Detection]
J -->|Success|K[Initialize Singletons<br/>Dependency Order]
J -->|Cycle Found|L[❌ Cycle Error]

K --> M[Status: READY<br/>Cache Populated]
M --> N[✅ Service Resolved]

L --> O[Status: FAILED<br/>Cache Cleared]
O --> P[❌ Bootstrap Failed]

G --> N

classDef statusNode fill: none, stroke: #2196f3, stroke-width: 2px, color: #ffffff
classDef processNode fill: none, stroke: #4caf50, stroke-width: 2px, color: #ffffff
classDef errorNode fill: none, stroke: #f44336, stroke-width: 2px, color: #ffffff
classDef decisionNode fill: none, stroke: #ff9800, stroke-width: 2px, color: #ffffff

class A, C,M, O statusNode
class B, D, F, I, K, G, N processNode
class H, L, P errorNode
class E, J decisionNode

3.3 Component Architecture¶

Component	Purpose	Key Features
`ContainerStatus`	State management enum	READY/PENDING/FAILED transitions
`BootstrapManager`	Orchestrates bootstrap lifecycle	Status transitions, error handling
`DependencyCycleDetector`	Graph-based dependency analysis	Uses `AdjacencyListGraph`, `topological_sort()`
`SingletonInitializer`	Ordered singleton resolution	Dependency-first initialization
`DiMetrics`	Bootstrap observability	Performance tracking, diagnostics

3.4 State Management & Recovery¶

The container lifecycle is managed through clear state transitions:

Registration Impact: Any service registration transitions container from READY → PENDING
Bootstrap Success: PENDING → READY with populated singleton cache
Bootstrap Failure: PENDING → FAILED with complete state reversion
Recovery Mechanism: New registration after failure enables FAILED → PENDING transition

3.5 Thread Safety & Concurrency¶

Bootstrap operations are designed for safe concurrent access:

Reentrant Locking: threading.RLock() enables same-thread resolve calls during bootstrap
Serialized Access: Multiple threads block until bootstrap completion
Atomic State Changes: Container status and cache modifications are atomic
Concurrent Resolution: Post-bootstrap resolution is fully concurrent

3.6 Integration with Existing Systems¶

The bootstrap system integrates seamlessly with existing components:

Phase 1 Compatibility: All existing registration and resolution APIs unchanged
Reflection Integration: Leverages loryth.common.reflection for dependency analysis
Graph Collection: Uses loryth.common.collections.graph for cycle detection and ordering
Independent Metrics: Simple DI metrics system separate from reflection metrics

📐 4. Implementation Details¶

4.1 Enhanced DiContainer Architecture¶

from enum import Enum


class ContainerStatus(Enum):
    """Container bootstrap status."""
    PENDING = "pending"  # Services registered, bootstrap needed
    READY = "ready"  # Bootstrap completed successfully
    FAILED = "failed"  # Bootstrap failed, recovery needed


class DiContainer:
    def __init__(self) -> None:
        self._items: list[DiContainerItem[Any]] = []
        self._cache: dict[type, Any] = {}
        self._bootstrap_manager = BootstrapManager(self)
        self._bootstrap_lock = threading.RLock()
        self._status = ContainerStatus.READY  # Start ready (no services)

    def bootstrap(self) -> None:
        """Manually trigger bootstrap process."""
        with self._bootstrap_lock:
            if self._status == ContainerStatus.READY:
                return  # Already bootstrapped

            try:
                self._bootstrap_manager.bootstrap()
                self._status = ContainerStatus.READY
            except Exception as e:
                self._status = ContainerStatus.FAILED
                # Revert to pre-bootstrap state
                self._cache.clear()
                raise

    def resolve[T](self, service_type: type[T]) -> T:
        """Resolve service with automatic bootstrap."""
        # Trigger bootstrap if needed
        if self._status == ContainerStatus.PENDING:
            self.bootstrap()
        elif self._status == ContainerStatus.FAILED:
            raise BootstrapError("Container in failed state, cannot resolve services")

        # Existing resolution logic from Phase 1
        return self._resolve_service(service_type)

    def validate_dependencies(self) -> None:
        """Validate dependency graph without bootstrapping."""
        detector = DependencyCycleDetector(self._dependencies)
        cycles = detector.detect_cycles()
        if cycles:
            raise DependencyCycleError(f"Circular dependencies detected: {cycles}")

4.2 Bootstrap Manager Implementation¶

class BootstrapManager:
    def __init__(self, container: DiContainer) -> None:
        self._container = container
        self._validator = BootstrapValidator(container)
        self._cycle_detector = DependencyCycleDetector()
        self._singleton_initializer = SingletonInitializer(container)

    def bootstrap(self) -> None:
        """Execute complete bootstrap process."""
        try:
            # Phase 1: Validate dependency graph
            self._validate_dependencies()

            # Phase 2: Detect circular dependencies
            self._detect_cycles()

            # Phase 3: Initialize all singletons
            self._initialize_singletons()

        except Exception as e:
            # Bootstrap failure should be clear and actionable
            raise BootstrapError(f"Bootstrap failed: {e}") from e

    def _validate_dependencies(self) -> None:
        """Validate all registered services have resolvable dependencies."""
        self._validator.validate_all_dependencies()

    def _detect_cycles(self) -> None:
        """Detect and report circular dependencies."""
        cycles = self._cycle_detector.detect_cycles(self._container._dependencies)
        if cycles:
            formatted_cycles = self._format_cycle_errors(cycles)
            raise DependencyCycleError(f"Circular dependencies detected:\n{formatted_cycles}")

    def _initialize_singletons(self) -> None:
        """Resolve all registered singleton services."""
        singleton_types = self._get_singleton_types()
        self._singleton_initializer.initialize_all(singleton_types)

    def _get_singleton_types(self) -> list[type]:
        """Get all service types registered as singletons."""
        return [
            item.type_ for item in self._container._items
            if item.lifecycle == ServiceLifecycle.SINGLETON
        ]

4.3 Dependency Cycle Detection¶

from loryth.common.collections.graph import AdjacencyListGraph, topological_sort


class DependencyCycleDetector:
    def __init__(self) -> None:
        self._graph: AdjacencyListGraph[type, None] = AdjacencyListGraph()

    def build_dependency_graph(self, container: "DiContainer") -> None:
        """Build dependency graph from container's registered services."""
        # Add all service types as nodes
        for item in container._items:
            if not self._graph.has_node(item.type_):
                self._graph.add_node(item.type_)

        # Analyze dependencies for each service and add edges
        for item in container._items:
            dependencies = self._analyze_service_dependencies(container, item)
            for dep_type in dependencies:
                if self._graph.has_node(dep_type):
                    # Edge from service to its dependency
                    self._graph.add_edge(item.type_, dep_type, None)

    def detect_cycle_via_topological_sort(self) -> None:
        """Detect cycles using topological sort - throws if cycle exists."""
        try:
            topological_sort(self._graph)
        except ValueError as e:
            if "cycle" in str(e).lower():
                raise DependencyCycleError("Circular dependency detected in service graph")
            raise

    def get_topological_order(self) -> list[type]:
        """Get services in dependency order (dependencies first)."""
        return list(topological_sort(self._graph))

    def _analyze_service_dependencies(self, container: "DiContainer", item: DiContainerItem) -> list[type]:
        """Analyze dependencies for a specific service using reflection."""
        if item.lifecycle == ServiceLifecycle.SINGLETON and callable(item.provider):
            # For type-based services, analyze constructor dependencies
            # This will be implemented in Phase 2.2
            return container._get_service_dependencies(item.type_)
        return []

4.4 Singleton Initialization¶

class SingletonInitializer:
    def __init__(self, container: DiContainer, cycle_detector: DependencyCycleDetector) -> None:
        self._container = container
        self._cycle_detector = cycle_detector

    def initialize_all_singletons(self) -> None:
        """Initialize all singleton services in dependency order."""
        # Get topological order from cycle detector (dependencies first)
        ordered_types = self._cycle_detector.get_topological_order()

        # Filter to only singleton services
        singleton_types = [
            service_type for service_type in ordered_types
            if self._is_singleton_service(service_type)
        ]

        for service_type in singleton_types:
            try:
                # Use container's resolve method to leverage existing logic
                self._container._resolve_service(service_type)
            except Exception as e:
                raise SingletonInitializationError(
                    f"Failed to initialize singleton {service_type.__name__}: {e}"
                ) from e

    def _is_singleton_service(self, service_type: type) -> bool:
        """Check if service type is registered as singleton."""
        item = self._container._find_provider(service_type)
        return item is not None and item.lifecycle == ServiceLifecycle.SINGLETON

4.5 Container Status Management¶

The container uses a three-state status enum to track bootstrap lifecycle:

READY: Container has no services or is successfully bootstrapped
PENDING: Services registered, bootstrap required before resolution
FAILED: Bootstrap failed, container unusable until recovery

Status transitions:

Initial state: READY (empty container)
On registration: READY → PENDING
On successful bootstrap: PENDING → READY
On bootstrap failure: PENDING → FAILED
On recovery (new registration): FAILED → PENDING

4.6 Dependency Graph Construction¶

Bootstrap builds dependency graph fresh using loryth.common.collections.graph.AdjacencyListGraph:

Graph Construction: Add all service types as nodes, analyze dependencies via reflection, add edges
Cycle Detection: Use topological_sort() from collections - throws ValueError if cycles exist
Topological Ordering: Get dependency-first resolution order from same topological sort
Performance: Single graph construction covers both cycle detection and ordering

4.7 Bootstrap Failure Recovery¶

Atomic bootstrap operations with complete state reversion:

Success: Cache populated, status → READY
Failure: Cache cleared, status → FAILED, preserve pre-bootstrap registrations
Recovery: Allow new registrations to reset status → PENDING

4.8 DI Metrics System¶

Simple, comprehensive metrics tracking separate from reflection system:

Tracked Metrics:

Bootstrap calls count and duration
Number of services (total, singletons, transients)
Average service initialization duration
Number of resolutions and average duration
Per-service initialization details and timing
Cycle detection attempts and results

Design Philosophy:

Evaluate alternative to reflection metrics
Simple data collection without complex infrastructure
Focus on actionable debugging information

4.9 Graph Collection Integration¶

Leverage existing loryth.common.collections.graph for dependency analysis:

Cycle Detection: Use topological_sort() - throws on cycles (no custom DFS needed)
Dependency Ordering: Same topological sort provides correct initialization order
Graph Type: AdjacencyListGraph[type, None] for service dependencies
Performance: O(V + E) complexity for both cycle detection and ordering

⚙️ 5. Semantics¶

5.1 Container Status Transitions¶

Initial State: READY (empty container, no services registered)
Registration Effect: Any service registration transitions READY → PENDING
Bootstrap Success: PENDING → READY (all singletons cached)
Bootstrap Failure: PENDING → FAILED (cache cleared, registrations preserved)
Recovery: New registration after failure transitions FAILED → PENDING

5.2 Bootstrap Triggers¶

Automatic: First call to resolve(), resolve_all(), or try_resolve() when status is PENDING
Manual: Explicit call to bootstrap() when status is PENDING
Failed State: Resolution calls on FAILED status throw BootstrapError
Ready State: Resolution calls on READY status proceed without bootstrap

5.3 Bootstrap Process Order¶

Graph Construction: Build AdjacencyListGraph with service dependencies via reflection
Cycle Detection: Use topological_sort() - throws ValueError if cycles exist
Singleton Initialization: Resolve singletons in topological order (dependencies first)
Factory Execution: Execute singleton factories during initialization
Cache Population: Store resolved singletons in container cache

5.4 Atomic Bootstrap Operations¶

All-or-Nothing: Complete success or complete failure with state reversion
State Reversion: Failed bootstrap clears cache, preserves pre-bootstrap registrations
Status Management: Failure sets status to FAILED, success sets to READY
Error Propagation: Original exception re-thrown after state cleanup

5.5 Thread Safety¶

Bootstrap Lock: threading.RLock() serializes bootstrap and resolution operations
Reentrant Operations: Same thread can call resolve during bootstrap
Concurrent Protection: Multiple threads block until bootstrap completes
Cache Consistency: Singleton cache remains consistent across concurrent access

🧪 6. Examples¶

6.1 Automatic Bootstrap¶

from loryth.common.di import Container

# Register services
container = Container()
container.register_singleton(UserRepository, SqlUserRepository)
container.register_singleton(UserService, UserService)  # depends on UserRepository

# First resolve triggers automatic bootstrap
user_service = container.resolve(UserService)  # Bootstrap happens here

6.2 Manual Bootstrap¶

# Register services
container.register_singleton(UserRepository, SqlUserRepository)
container.register_singleton(UserService, UserService)

# Manual bootstrap for early validation
try:
    container.bootstrap()  # All singletons resolved and validated
    print("Bootstrap successful - all dependencies valid")
except DependencyCycleError as e:
    print(f"Circular dependency detected: {e}")
except BootstrapError as e:
    print(f"Bootstrap failed: {e}")

6.3 Dependency Validation¶

# Register services with circular dependency
container.register_singleton(ServiceA, ServiceA)  # depends on ServiceB
container.register_singleton(ServiceB, ServiceB)  # depends on ServiceA

# Validate without initializing
try:
    container.validate_dependencies()
except DependencyCycleError as e:
    print(f"Validation failed: {e}")
    # Output: "Circular dependencies detected: ServiceA -> ServiceB -> ServiceA"

✅ 7. Acceptance Criteria¶

⏳ bootstrap() method resolves all registered singletons and caches them
⏳ Automatic bootstrap triggered on first resolve call
⏳ validate_dependencies() detects circular dependencies without initialization
⏳ Bootstrap process is idempotent - multiple calls are safe
⏳ Thread-safe bootstrap with proper locking mechanisms
⏳ Clear error messages for circular dependencies with service names
⏳ Bootstrap failure prevents container usage until reconfiguration
⏳ Topological sorting ensures dependencies are resolved before dependents
⏳ Singleton initialization happens in correct dependency order
⏳ Manual bootstrap option for early validation scenarios

🧪 8. Test Matrix¶

8.1 Unit Test Coverage¶

Container Status Management¶

⏳ Initial State: Container starts in READY status with empty cache
⏳ Registration Transitions: READY → PENDING on service registration
⏳ Bootstrap Success: PENDING → READY with populated cache
⏳ Bootstrap Failure: PENDING → FAILED with cleared cache
⏳ Recovery Transitions: FAILED → PENDING on new registration

Bootstrap Manager¶

⏳ Manual Bootstrap: Explicit bootstrap() call succeeds
⏳ Automatic Bootstrap: First resolve triggers bootstrap
⏳ Idempotent Bootstrap: Multiple bootstrap calls on READY container
⏳ Bootstrap Failure Handling: Exception propagation with state reversion
⏳ Status Validation: Bootstrap only runs when status is PENDING

Dependency Analysis¶

⏳ Graph Construction: AdjacencyListGraph built correctly from services
⏳ Simple Dependencies: Linear dependency chain (A → B → C)
⏳ Complex Dependencies: Diamond dependencies (A → B,C → D)
⏳ No Dependencies: Services with no constructor dependencies
⏳ Self-Registration: Service depends on interface it implements

Cycle Detection¶

⏳ Simple Cycle: Two-service cycle (A → B → A)
⏳ Complex Cycle: Multi-service cycle (A → B → C → A)
⏳ Deep Cycle: Cycle in deep dependency chain
⏳ No Cycle Detection: Valid dependency graph passes
⏳ Error Handling: DependencyCycleError with clear message

Singleton Initialization¶

⏳ Dependency Order: Dependencies resolved before dependents
⏳ Factory Execution: Singleton factories executed during bootstrap
⏳ Cache Population: Resolved singletons stored in cache
⏳ Initialization Failure: Single service failure fails entire bootstrap
⏳ Mixed Lifecycles: Singletons and transients handled correctly

Thread Safety¶

⏳ Concurrent Bootstrap: Multiple threads trigger bootstrap safely
⏳ Bootstrap Blocking: Resolution blocks during bootstrap
⏳ Reentrant Resolution: Same thread can resolve during bootstrap
⏳ Lock Behavior: RLock allows reentrant bootstrap calls
⏳ Cache Consistency: Thread-safe cache access

Error Scenarios¶

⏳ Invalid Registration: Type mismatch registration fails
⏳ Missing Dependencies: Unregistered dependency detection
⏳ Factory Exceptions: Factory failure during bootstrap
⏳ Constructor Exceptions: Constructor failure during resolution
⏳ Failed State Resolution: Resolve calls on FAILED status throw

8.2 Integration Test Coverage¶

Complete Bootstrap Workflows¶

⏳ End-to-End Success: Registration → Bootstrap → Resolution
⏳ Automatic Bootstrap Flow: Registration → First Resolve → Success
⏳ Manual Bootstrap Flow: Registration → Manual Bootstrap → Resolution
⏳ Bootstrap Recovery: Failure → New Registration → Retry → Success
⏳ Mixed Service Types: Singletons, transients, factories, instances

Complex Dependency Scenarios¶

⏳ Deep Dependency Chains: 5+ level dependency hierarchies
⏳ Wide Dependency Trees: Services with multiple dependencies
⏳ Shared Dependencies: Multiple services depend on same service
⏳ Circular Reference Detection: Complex circular dependency scenarios
⏳ Partial Dependency Resolution: Some services resolvable, others not

Performance & Concurrency¶

⏳ Concurrent Access Patterns: Multiple threads accessing container
⏳ Bootstrap Performance: Large service graphs (50+ services)
⏳ Memory Usage: Bootstrap impact on container memory
⏳ Metrics Collection: Bootstrap metrics accuracy
⏳ Thread Contention: High-concurrency bootstrap scenarios

Integration with Phase 1¶

⏳ API Compatibility: All Phase 1 APIs work unchanged
⏳ Existing Container Migration: Phase 1 → Phase 2 upgrade
⏳ Mixed Resolution: resolve(), resolve_all(), try_resolve()
⏳ Cache Behavior: Singleton caching across resolution methods
⏳ Registration Compatibility: All registration types supported

Reflection Integration¶

⏳ Constructor Analysis: Dependency extraction via reflection
⏳ Type Validation: Service type compatibility checking
⏳ Generic Types: Generic service registration and resolution
⏳ Protocol Support: Protocol-based service registration
⏳ Error Integration: Reflection errors during bootstrap

8.3 Test Organization¶

Unit Tests Location¶

tests/unit/di/bootstrap/
├── test_container_status.py
├── test_bootstrap_manager.py
├── test_dependency_analysis.py
├── test_cycle_detection.py
├── test_singleton_initialization.py
├── test_thread_safety.py
└── test_error_scenarios.py

Integration Tests Location¶

tests/integration/di/bootstrap/
├── test_bootstrap_workflows.py
├── test_complex_dependencies.py
├── test_performance_concurrency.py
├── test_phase1_integration.py
└── test_reflection_integration.py

Test Helpers & Resources¶

tests/resources/di/bootstrap/
├── simple_services.py      # Basic service classes
├── complex_dependencies.py # Complex dependency scenarios
├── circular_services.py    # Services with circular dependencies
└── performance_services.py # Large service graphs for testing

🚀 9. Rollout and Migration¶

9.1 Implementation Phases¶

Phase 2.1: Bootstrap Manager Infrastructure & Metrics

Implement BootstrapManager class with basic lifecycle
Add ContainerStatus enum with three-state management (READY/PENDING/FAILED)
Implement bootstrap trigger integration in resolve methods
Create simple DI metrics system with comprehensive tracking
Container status transitions and state management

Phase 2.2: Dependency Analysis & Graph Integration

Implement DependencyCycleDetector using loryth.common.collections.graph
Build dependency graph fresh during bootstrap using AdjacencyListGraph
Integrate topological_sort() for cycle detection (throws on cycles)
Build dependency analysis via reflection for constructor inspection

Phase 2.3: Singleton Initialization & Thread Safety

Implement SingletonInitializer using topological ordering from graph
Add thread-safe bootstrap with threading.RLock()
Atomic bootstrap operations with state reversion on failure
Factory execution during bootstrap for singleton lifecycles
Per-service initialization with detailed error reporting

Phase 2.4: Enhanced Observability & Error Handling

Complete metrics integration with per-service timing and details
Bootstrap-specific exception hierarchy (BootstrapError, etc.)
Enhanced error reporting with dependency chain information
Performance monitoring and diagnostic capabilities

9.2 Backward Compatibility¶

All Phase 1 functionality remains unchanged
Bootstrap is automatic and transparent to existing code
No breaking changes to registration or resolution APIs

⚠️ 10. Risks and Mitigations¶

10.1 Performance Risk¶

Risk: Bootstrap overhead for simple applications with few dependencies Mitigation: Benchmark bootstrap time, provide manual control options

10.2 Deadlock Risk¶

Risk: Thread deadlock during concurrent bootstrap attempts Mitigation: Use RLock for reentrant locking, comprehensive deadlock testing

10.3 Memory Usage Risk¶

Risk: Increased memory usage from early singleton initialization Mitigation: Provide lazy initialization options, memory usage monitoring

📈 11. Progress¶

Legend: ✅ = completed, 🚧 = in progress, ⏳ = pending, ❌ = cancelled

Phase 2.1: Bootstrap Manager Infrastructure & Metrics¶

✅ Implement BootstrapManager class with lifecycle management
✅ Add ContainerStatus enum (READY/PENDING/FAILED)
✅ Integrate bootstrap triggers in resolve(), resolve_all(), try_resolve()
✅ Create DI metrics system with comprehensive tracking
✅ Implement container status transitions

Phase 2.2: Dependency Analysis & Graph Integration¶

✅ Implement DependencyCycleDetector using collections graph
✅ Build dependency graph with AdjacencyListGraph[type, None]
✅ Integrate topological_sort() for cycle detection
✅ Implement reflection-based dependency analysis

Phase 2.3: Singleton Initialization & Thread Safety¶

❌ Implement SingletonInitializer with graph ordering - NOT IMPLEMENTED (functionality exists in BootstrapManager)
🚧 Add thread-safe bootstrap with threading.RLock() - PARTIALLY IMPLEMENTED
🚧 Implement atomic operations with state reversion - PARTIALLY IMPLEMENTED
✅ Add factory execution for singleton lifecycles (implemented in BootstrapManager)

Phase 2.4: Enhanced Observability & Error Handling¶

✅ Complete per-service metrics and timing
✅ Implement bootstrap exception hierarchy
✅ Add enhanced error reporting with dependency chains
✅ Create comprehensive unit and integration tests

📝 12. Changelog¶

2025-10-02: Initial draft technical design created
2025-10-03: Enhanced with container status enum, graph collection integration, and comprehensive implementation details
2025-10-03: ✅ Phase 2.1 COMPLETED - Implemented bootstrap manager infrastructure with comprehensive test suite (67 test scenarios, 305 total tests passing)
2025-10-03: ✅ Phase 2.2 COMPLETED - Implemented dependency analysis and graph integration with cycle detection
2025-10-03: 🚧 Phase 2.3 IN PROGRESS - Singleton initialization functionality exists in BootstrapManager (not separate class), thread safety partially implemented
2025-10-03: ✅ Phase 2.4 COMPLETED - Enhanced observability and error handling
2025-10-03: 📋 ANALYSIS COMPLETED - Current implementation status reviewed and gaps identified
2025-10-03: 📋 IMPLEMENTATION PLAN CREATED - Comprehensive implementation plan created to address gaps ( see 010-di-implementation-plan.md)
2025-10-03: 📋 SUMMARY DOCUMENT CREATED - Analysis summary created (see 010-di-summary.md)

📖 13. Glossary¶

Bootstrap: Process of initializing the DI container, detecting cycles, and resolving all singletons in dependency order
Container Status: Three-state enum tracking bootstrap lifecycle (READY/PENDING/FAILED)
Dependency Cycle: Circular dependency where services depend on each other directly or indirectly
Dependency Graph: Directed graph representing service dependencies, built using AdjacencyListGraph[type, None]
Topological Sort: Algorithm from loryth.common.collections.graph that orders services by dependencies and detects cycles
Atomic Bootstrap: All-or-nothing bootstrap operation that reverts state completely on any failure
Singleton Initialization: Process of creating and caching singleton service instances in dependency order
State Reversion: Recovery mechanism that clears cache and preserves only pre-bootstrap registrations on failure
Bootstrap Trigger: Automatic bootstrap initiation on first resolve call when container status is PENDING
DI Metrics: Simple metrics system tracking bootstrap performance, service counts, and initialization timing