and there are no missing null checks.

## Decision

Use "NullAway" in JSpecify mode to check for null-related errors in Java code.

Consider improper uses of `null` detected by NullAway a compilation error (not a warning, and not a separate CI job to test).

Do not suppress NullAway errors without a justification.

    override fun execute(details: CompatibilityCheckDetails<NullawayState>) {
        with(details) {
            when {
                // Nullaway-enabled targets must not depend on nullaway-disabled ones.
                // They can depend on nullaway-undefined, which any external dependency is going to be.
                producerValue == NullawayState.DISABLED && consumerValue == NullawayState.ENABLED -> incompatible()

            val uncheckedCount = projectsWithUncheckedDeps.size

            if (enabledCount == seenProjectsCount) {
                println("All have NullAway enabled.")
            } else {
                println("NullAway enabled in ${enabledCount} ${projectS(enabledCount)}.")

                if (projectsToEnableNullaway.isNotEmpty()) {

import gradlebuild.nullaway.NullawayAttributes
import gradlebuild.nullaway.NullawayCompatibilityRule
import gradlebuild.nullaway.NullawayState
import gradlebuild.nullaway.NullawayStatusTask
import net.ltgt.gradle.errorprone.CheckSeverity
import net.ltgt.gradle.errorprone.errorprone
import net.ltgt.gradle.nullaway.nullaway

/*
 * Copyright 2022 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package gradlebuild.nullaway

import org.gradle.api.DefaultTask
import org.gradle.api.artifacts.ArtifactCollection
import org.gradle.api.artifacts.result.ResolvedArtifactResult
import org.gradle.api.provider.Property

 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.

 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.

 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.

 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.

 *       even on an {@code ImmutableMap<K, @NonNull String>}.
 * </ul>
 *
 * <p>Consumers of this annotation include:
 *
 * <ul>
 *   <li>NullAway, which <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.