Use instance factory for value classes with any() matcher #1403
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Fixes mockk#1199: "registerInstanceFactory supplier is not used for value classes" When using `registerInstanceFactory` for a value class that has an `init{}` block for validation, the factory was not being invoked when the value class was used as an argument with the `any()` matcher. This would lead to MockK attempting to create a default instance of the value class, potentially violating the `init` block's requirements and causing an `IllegalArgumentException`. This commit addresses the issue by modifying `JvmSignatureValueGenerator.signatureValue`. Now, when a signature value is needed for a value class (e.g., for an `any()` matcher), the code first attempts to obtain an instance via `instantiateViaInstanceFactoryRegistry`. If a factory is registered for the value class, it will be used. Otherwise, MockK falls back to the previous behavior of creating an instance from the boxed underlying type. A new test case was added to `ValueClassTest.kt` to specifically reproduce this bug and verify the fix. This test, along with other relevant tests, now passes.
Raibaz
approved these changes
Jun 15, 2025
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Fixes #1199: "registerInstanceFactory supplier is not used for value classes"
When using
registerInstanceFactoryfor a value class that has aninit{}block for validation, the factory was not being invoked when the value class was used as an argument with theany()matcher. This would lead to MockK attempting to create a default instance of the value class, potentially violating theinitblock's requirements and causing anIllegalArgumentException.This commit addresses the issue by modifying
JvmSignatureValueGenerator.signatureValue. Now, when a signature value is needed for a value class (e.g., for anany()matcher), the code first attempts to obtain an instance viainstantiateViaInstanceFactoryRegistry. If a factory is registered for the value class, it will be used. Otherwise, MockK falls back to the previous behavior of creating an instance from the boxed underlying type.A new test case was added to
ValueClassTest.ktto specifically reproduce this bug and verify the fix. This test, along with other relevant tests, now passes.This PR was computer generated, then refactored by me.