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VOOZH | about |
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VOOZH | about |
This document covers the exception handling mechanisms in the Hypervel Container system, focusing on the BindingResolutionException class and its role in the dependency resolution pipeline. This page explains the exception class structure, PSR-11 compliance requirements, scenarios that trigger exceptions, and recommended handling strategies.
For information about the dependency resolution process itself, see Dependency Resolution. For details on method invocation errors, see Method Invocation & Dependency Injection.
The BindingResolutionException is the primary exception type thrown by the Hypervel Container during service resolution failures. It extends PHP's base Exception class while implementing PSR-11's ContainerExceptionInterface, providing standard error handling semantics across PSR-11 compatible systems.
The class definition is minimal, inheriting all functionality from its parent classes:
src/BindingResolutionException.php10-12
| Property | Type | Description |
|---|---|---|
| Namespace | Hypervel\Container | Package-specific namespace |
| Parent Class | Exception | Standard PHP exception |
| Interfaces | ContainerExceptionInterface | PSR-11 compliance marker |
| Methods | (inherited) | All exception methods from base Exception |
Sources: src/BindingResolutionException.php1-13
The BindingResolutionException implements Psr\Container\ContainerExceptionInterface to ensure compliance with the PSR-11 Container Interface standard. This interface serves as a marker for container-specific exceptions, distinguishing them from general application errors.
The ContainerExceptionInterface from PSR-11 defines the base exception type for all container-related errors. According to the PSR-11 specification, this interface should be implemented by exceptions thrown during:
By implementing this interface, BindingResolutionException ensures that applications can:
Sources: src/BindingResolutionException.php8-11
The BindingResolutionException is thrown during various failure conditions in the container resolution pipeline. Understanding these scenarios helps in proper error handling and debugging.
| Scenario | Description | Typical Message |
|---|---|---|
| Unbound Service | Attempting to resolve a service that has no binding | "Target [ClassName] is not instantiable" |
| Circular Dependency | Service A depends on B, which depends on A | "Circular dependency detected while resolving [ClassName]" |
| Unresolvable Parameter | Constructor parameter cannot be auto-resolved | "Unresolvable dependency resolving [Parameter] in class [ClassName]" |
| Abstract Class | Attempting to instantiate an abstract class without concrete binding | "Target [AbstractClass] is not instantiable" |
| Interface Resolution | Attempting to resolve an interface without implementation binding | "Target [InterfaceName] is not instantiable" |
| Invalid Callable | Method binding references invalid callable | "Method [method] does not exist on [ClassName]" |
| Type Mismatch | Resolved instance does not match expected type | "Resolved instance is not an instance of [ClassName]" |
Sources: Based on resolution pipeline from high-level system diagrams (Diagram 4) and PSR-11 standard behavior
When a BindingResolutionException is thrown, it carries contextual information inherited from PHP's base Exception class. This information is crucial for debugging resolution failures.
| Property | Method | Description |
|---|---|---|
| Message | getMessage() | Human-readable error description including the service name and failure reason |
| Code | getCode() | Numeric error code (typically 0 for resolution exceptions) |
| File | getFile() | File path where the exception was thrown |
| Line | getLine() | Line number where the exception was thrown |
| Stack Trace | getTrace() | Array of stack frames showing the call path |
| Previous Exception | getPrevious() | Wrapped exception if this exception was triggered by another |
The container often wraps underlying exceptions (such as ReflectionException) in a BindingResolutionException to maintain PSR-11 compliance while preserving the original error context:
This allows callers to:
getPrevious()Sources: src/BindingResolutionException.php10-12
Proper exception handling ensures graceful degradation when container resolution fails. The following strategies apply to different contexts within application code.
When a service is optional or has a reasonable default, catch the exception and provide fallback behavior:
During application initialization, let exceptions propagate to prevent running with incomplete configuration:
When multiple implementations exist, attempt resolution with fallback options:
Add context-specific information before propagating the exception:
Sources: Based on container resolution patterns from high-level system architecture
The BindingResolutionException integrates with various container operations beyond basic make() calls. Understanding where exceptions can originate helps in comprehensive error handling.
| Container Method | Can Throw Exception | Scenario |
|---|---|---|
make($abstract) | ✓ Yes | Primary resolution failures |
get($id) | ✓ Yes | PSR-11 compliant resolution failures |
call($callback) | ✓ Yes | Method parameter resolution failures |
bind($abstract, $concrete) | ✗ No | Binding registration is lazy |
instance($abstract, $instance) | ✗ No | Direct instance storage |
extend($abstract, $closure) | Delayed | Thrown when extended service is resolved |
resolving($abstract, $callback) | Delayed | Thrown during callback execution if callback fails |
Exceptions can also be thrown from user-defined callbacks registered via lifecycle methods:
Note: User-defined callbacks (resolving, afterResolving) may throw any exception type, not just BindingResolutionException. The container does not wrap these exceptions.
Sources: src/BindingResolutionException.php1-13 based on container resolution pipeline from Diagram 4
When a BindingResolutionException occurs, systematic debugging techniques help identify the root cause quickly.
| Debug Step | Action | Information Gained |
|---|---|---|
| 1. Examine Message | Read getMessage() | Identifies which service failed and basic reason |
| 2. Check Bindings | Verify service is bound in container | Determines if service is registered |
| 3. Review Dependencies | Examine constructor of failing class | Reveals what dependencies are required |
| 4. Trace Previous | Follow getPrevious() chain | Uncovers underlying reflection or type errors |
| 5. Inspect Stack Trace | Review getTrace() | Shows call path leading to failure |
| 6. Test in Isolation | Manually instantiate service | Validates if issue is with service or dependencies |
To minimize resolution exceptions in production:
Sources: Based on container architecture and PSR-11 standard practices
The BindingResolutionException is a lightweight PSR-11 compliant exception class that signals service resolution failures in the Hypervel Container. Key points:
Exception and implements ContainerExceptionInterface src/BindingResolutionException.php10-12For more information on the resolution process, see Dependency Resolution. For configuration that prevents exceptions, see Configuration & Initialization.
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