Enable AOT repository generation by default

[HyunSangHan]

Resolves: #3899

Currently, to leverage AOT optimized repositories on the JVM with Spring Data JPA, users need to explicitly set both spring.aot.enabled=true and spring.aot.repositories.enabled=true.

This change updates the behavior so that if Spring Framework's AOT processing is active (e.g., spring.aot.enabled=true is set, or the application is being prepared for a native image), Spring Data JPA's AOT repository generation (spring.aot.repositories.enabled) will also be enabled by default.

[mp911de]

Thanks for submitting a pull request. I left a few comments so you can improve your test code.

[mp911de]

Setting system properties can be achieved via @SetSystemProperty(…) to avoid leaking system properties state if the test fails.

[HyunSangHan]

@mp911de
Thank you for your feedback! I completely understand your point and I agree with you.
To use @SetSystemProperty(…) and @ClearSystemProperty, we need to add the junit-pioneer dependency.
Do you think it would be a good idea to include junit-pioneer in this project?

[mp911de]

We have it already in Spring Data MonoDB, feel free to include it in JPA as well.

[mp911de]

You could use @ClearSystemProperty here

[mp911de]

This snippet could be extracted into a utility method within the test class to not repeat ourselves.

[HyunSangHan]

Thank you. I created a private method and refactored these.

[mp911de]

This could be handled by system properties as well as GenericApplicationContext creates StandardEnvironment that utilizes system properties and system environment for property sources. That would simplify the test arrangement.

[HyunSangHan]

Good point. I changed to use SetSystemProperty for this!

[mp911de]

Thank you for your contribution. That's merged and polished now.