Add Readiness and Slice support

[molon]

This pull request introduces support for providing and resolving multiple values of the same type using a new Element[T] and Slice[T] pattern in the inject package. It also updates the dependency cycle detection and internal data structures to handle these new types, improves error checking for function input/output types, and expands the documentation with comprehensive examples and explanations for these new features.

Key changes:

New feature: Multiple values of the same type

• Added Element[T] and Slice[T] types to allow multiple providers for the same type and to resolve them as a slice ([]T). Includes new helper functions and type checks in element.go, and updated README with usage examples. [1] [2] [3] [4]

Dependency injection core updates

• Changed internal maps (values, providers) to use a new typeKey struct (type + index) to support multiple providers for Element[T] types. Added elementCounts to track the number of providers for each element type. [1] [2]
• Updated dependency cycle detection and resolution logic to work with typeKey instead of just reflect.Type, and to correctly handle Element[T] and Slice[T] types. [1] [2] [3]

API and error handling improvements

• Added IsInputTypeAllowed and IsOutputTypeAllowed to restrict usage of Element[T] and Slice[T] to appropriate contexts (inputs/outputs). Improved error messages for invalid function signatures. [1] [2]

Documentation enhancements

• Expanded README with detailed documentation and code samples for Element[T], Slice[T], readiness probes, and nested lifecycles. Clarified usage and constraints for new features. [1] [2] [3] [4]
• Moved and improved signal handling and readiness probe documentation for better clarity.

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References:
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]Provide context or links (Jira ticket, Slack thread) for both the reviewer and your future self:

• Jira ticket:
• Slack thread:

[Copilot]

Pull request overview

This pull request introduces support for providing and resolving multiple values of the same type using Element[T] and Slice[T] patterns in the inject package, along with readiness probe functionality for the lifecycle package to enable blocking startup until services are ready.

Key changes:

• Multiple values support: New Element[T] and Slice[T] types allow multiple providers for the same type T, resolved as a slice
• Readiness probes: Optional lifecycle readiness probes that block Start() until all services signal ready
• Internal refactoring: Updated internal data structures from reflect.Type to typeKey (type + index) to support Element indexing

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
element.go	Implements Element[T] and Slice[T] types with helper functions for type checking and extraction
element_test.go	Comprehensive test coverage for Element[T] and Slice[T] functionality including edge cases
inject.go	Core dependency injection updates: typeKey-based maps, resolveSlice logic, and input/output type validation
cycle.go	Updated dependency cycle detection to work with typeKey and handle Slice[T] dependencies on Element[T] providers
inject_test.go	Additional test cases for Build() method with constructor arguments
lifecycle/readiness.go	New ReadinessProbe implementation with Signal() and Error() methods
lifecycle/readiness_test.go	Test coverage for readiness probes including multiple probes and nested lifecycles
lifecycle/lifecycle.go	Integration of readiness probes into lifecycle Start() with dual collection mechanism
README.md	Documentation updates for Element/Slice usage, readiness probes, and nested lifecycles

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[Copilot]

@molon I've opened a new pull request, #10, to work on those changes. Once the pull request is ready, I'll request review from you.

[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated no new comments.

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