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Screenshot 2025-07-17 at 14.01.33.png

`MapProperty` questions:
• Is it possible to have `null` as a value?
• Having `MapProperty&lt;String, Any?&gt;` displays an error in my IDE but compiles fine. Where is the disconnect? How come the KIJP knows that the bound is non nullable?

In 8.14.3 the IDE does not show an error.
But with 9+ the nullable annotations were changed to use the JSpecify annotations which provide better results.
The `org.gradle.api.provider` package is annotated with `@NullMarked` which means that anything that is not annotated as nullable is non-null and so the V is a non-nullable type.

The `put` already shows an error in IDE already if you give `null` with 8.14.3 as there the old nullable annotations already work too.

And a `provider { null }` would anyway not work, as that is an absent provider, so even if you could have `null` as value, then only as direct value not as provider.

&gt; In 8.14.3 the IDE does not show an error.
This is what gets me confused, I compile against `8.0` so where does the IDE gets that information from?

&gt; The `org.gradle.api.provider` package is annotated with `@NullMarked`
TIL about package level annotations :til:
Turns out <https://github.com/gradle/gradle/blob/0714a352362228c5f4f8052dad671280e03202e8/subprojects/core-api/src/main/java/org/gradle/package-info.java#L20|all of >`org.gradle`<https://github.com/gradle/gradle/blob/0714a352362228c5f4f8052dad671280e03202e8/subprojects/core-api/src/main/java/org/gradle/package-info.java#L20| is now annotated as >`NullMarked` ?

That explains the error using 9+, thanks!

I'm still not getting where the IDE gets that information from, maybe I have several `gradle-api` in my compile classpath :thinking_face:

Maybe, if I just have an 8.0.2 build I also do not get IDE complaint about the declaration but about the usage

image.png

But well, having the error is more correct than not having the error actually

Unless of course `null` would be a valid value

Exactly, with Gradle 9 some previously "valid" code now fails to compile or so

restore the heating space bar :upside_down_face:

That's sad, but you also couldn't add `null` before anyway

As you see in the screenshot, there is an error on the `put` and it also does not compile with 8.14.3

Or well, it compiles but fails at runtime

```&gt; Configure project :
w: file:///D:/Sourcecode/other/showcase/build.gradle.kts:55:16: Type mismatch: inferred type is Any? but Any was expected

FAILURE: Build failed with an exception.

* Where:
Build file 'D:\Sourcecode\other\showcase\build.gradle.kts' line: 55

* What went wrong:
Cannot add an entry with a null value to a property of type Map.```

<https://github.com/gradle/gradle/blob/master/platforms/core-configuration/model-core/src/main/java/org/gradle/api/internal/provider/DefaultMapProperty.java#L187|https://github.com/gradle/gradle/blob/master/platforms/core-configuration/model-co[…]n/java/org/gradle/api/internal/provider/DefaultMapProperty.java>

Alright, tried a minimal reproducer with only `dev.gradleplugins:gradle-api:8.0` in the compile classpath, the IDE error actually depends on the Gradle wrapper version :shrug:

Probably an IJ issue applying the package level annotation from the wrapper version

Opened <https://youtrack.jetbrains.com/issue/KTIJ-34929/The-Kotlin-IJ-plugin-display-errors-based-on-the-Gradle-wrapper-version-not-the-compile-version>