feat(mixin): add IMixin interface and Construct.with() method#2843
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feat(mixin): add IMixin interface and Construct.with() method#2843
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Implements the constructs package parts of RFC-0814 (CDK Mixins). Adds the `IMixin` interface with `supports()` and `applyTo()` methods, and the `with()` method on `Construct` and `IConstruct` for fluent mixin application across construct trees.
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### Issue # (if applicable) Related RFC: aws/aws-cdk-rfcs#824 ### Reason for this change Aligns the implementation with the latest version of the [Mixins RFC](aws/aws-cdk-rfcs#824). The `.with()` method previously iterated over constructs first, then mixins. This meant that mixins were not guaranteed to be applied in the order they were passed to the method. Additionally, if a mixin added new constructs to the tree, subsequent mixins in the same call could unexpectedly visit those newly added constructs. ### Description of changes Changed the loop order so that mixins are applied in order. The list of constructs is now captured at the start of the call, ensuring that constructs added by a mixin will not be visited by subsequent mixins. Users who need subsequent mixins to apply to added constructs can use multiple `.with()` calls. Also improved variable naming for clarity (`c` → `construct`, `m` → `mixin`). ### Describe any new or updated permissions being added N/A ### Description of how you validated changes Existing tests pass. This behavior is explicitly tested in aws/constructs#2843. ### Checklist - [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md) ---- *By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*
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### Issue # (if applicable) Related RFC: aws/aws-cdk-rfcs#824 ### Reason for this change Aligns the implementation with the latest version of the [Mixins RFC](aws/aws-cdk-rfcs#824). The `.with()` method previously iterated over constructs first, then mixins. This meant that mixins were not guaranteed to be applied in the order they were passed to the method. Additionally, if a mixin added new constructs to the tree, subsequent mixins in the same call could unexpectedly visit those newly added constructs. ### Description of changes Changed the loop order so that mixins are applied in order. The list of constructs is now captured at the start of the call, ensuring that constructs added by a mixin will not be visited by subsequent mixins. Users who need subsequent mixins to apply to added constructs can use multiple `.with()` calls. Also improved variable naming for clarity (`c` → `construct`, `m` → `mixin`). ### Describe any new or updated permissions being added N/A ### Description of how you validated changes Existing tests pass. This behavior is explicitly tested in aws/constructs#2843. ### Checklist - [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md) ---- *By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*
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The default version of the `constructs` library for CDK 2.x projects has been stuck at `10.0.5` since CDK 2 was first introduced. Bumping the default to `10.5.1` enables support for CDK Mixins out of the box. Constructs `10.5.0` introduced the `IMixin` interface and `Construct.with()` method (aws/constructs#2843), allowing newly created projects to use this feature without manually upgrading their constructs dependency. Additionally, the default for `cdkVersion` is updated to `2.189.1`, which is the oldest CDK version without a published security advisory. This makes it a suitable minimum version for CDK Construct Libraries. Only affects new projects, which will now be created by putting this version into the generated projen RC file. --- By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. --------- Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
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The default version of the `constructs` library for CDK 2.x projects has been stuck at `10.0.5` since CDK 2 was first introduced. Bumping the default to `10.5.1` enables support for CDK Mixins out of the box. Constructs `10.5.0` introduced the `IMixin` interface and `Construct.with()` method (aws/constructs#2843), allowing newly created projects to use this feature without manually upgrading their constructs dependency. Additionally, the default for `cdkVersion` is updated to `2.189.1`, which is the oldest CDK version without a published security advisory. This makes it a suitable minimum version for CDK Construct Libraries. Only affects new projects, which will now be created by putting this version into the generated projen RC file. --- By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. --------- Signed-off-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com> Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
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This PR implements the
constructspackage parts of RFC-0814: CDK Mixins.CDK Mixins are composable, reusable abstractions that can be applied to any construct. This change adds the foundational support to the
constructslibrary, enabling the fluent.with()API described in the RFC.Changes
The
IMixininterface defines the contract for mixins with two methods:supports(construct)- determines if a mixin can be applied to a given constructapplyTo(construct)- applies the mixin functionality to the targetThe
with()method is added toConstructandIConstruct, allowing mixins to be applied fluently. When called, it traverses the construct tree and applies each mixin to all supported constructs.Why
Mixins are a new way to build abstractions, that does not rely on the construct level approach many implementors use. They allow users to employ a mix and match approach for features that doesn't lock consumers into specific implementations.