Add support for -XepOpt:NullAway:CustomContractAnnotations

Author: tbroyer

README.md

@@ -101,3 +101,4 @@ Each property (except for `severity`) maps to an `-XepOpt:NullAway:[propertyName
 | `exhaustiveOverride`           | (`isExhaustiveOverride` with Kotlin DSL) If set to true, NullAway will check every method to see whether or not it overrides a method of a super-type, rather than relying only on the `@Override` annotation.
 | `acknowledgeAndroidRecent`     | If set to true, treats `@RecentlyNullable` as `@Nullable`, and `@RecentlyNonNull` as `@NonNull`; requires that `acknowledgeRestrictiveAnnotations` is also set to true.
 | `checkContracts`               | If set to true, NullAway will check `@Contract` annotations.
+| `customContractAnnotations`    | A list of annotations that should be considered equivalent to `@Contract` annotations.

src/main/kotlin/net/ltgt/gradle/nullaway/NullAwayOptions.kt

@@ -144,6 +144,10 @@ open class NullAwayOptions internal constructor(
     @get:Input @get:Optional
     val checkContracts = objectFactory.property<Boolean>()
 
+    /** A list of annotations that should be considered equivalent to `@Contract` annotations; maps to `-XepOpt:NullAway:CustomContractAnnotations`. */
+    @get:Input @get:Optional
+    val customContractAnnotations = objectFactory.listProperty<String>()
+
     internal fun asArguments(): Iterable<String> = sequenceOf(
         "-Xep:NullAway${severity.getOrElse(CheckSeverity.DEFAULT).asArg}",
         listOption("AnnotatedPackages", annotatedPackages),
@@ -166,7 +170,8 @@ open class NullAwayOptions internal constructor(
         stringOption("AutoFixSuppressionComment", autoFixSuppressionComment),
         booleanOption("HandleTestAssertionLibraries", handleTestAssertionLibraries),
         booleanOption("AcknowledgeAndroidRecent", acknowledgeAndroidRecent),
-        booleanOption("CheckContracts", checkContracts)
+        booleanOption("CheckContracts", checkContracts),
+        listOption("CustomContractAnnotations", customContractAnnotations)
     )
         .filterNotNull()
         .asIterable()

src/test/kotlin/net/ltgt/gradle/nullaway/AbstractPluginIntegrationTest.kt

@@ -146,6 +146,7 @@ abstract class AbstractPluginIntegrationTest(
                     handleTestAssertionLibraries.set(true)
                     acknowledgeAndroidRecent.set(true)
                     checkContracts.set(true)
+                    customContractAnnotations.add("com.example.Contract")
                 }
             }
             """.trimIndent()

src/test/kotlin/net/ltgt/gradle/nullaway/GroovyDslIntegrationTest.kt

@@ -109,6 +109,7 @@ class GroovyDslIntegrationTest {
                     handleTestAssertionLibraries = true
                     acknowledgeAndroidRecent = true
                     checkContracts = true
+                    customContractAnnotations = ["com.example.Contract"]
                 }
             }
             """.trimIndent()