Add options for enabling incremental and incremental logging

Author: ZacSweers

ksp/src/main/kotlin/com/tschuchort/compiletesting/Ksp.kt

@@ -44,6 +44,26 @@ var KotlinCompilation.kspArgs: MutableMap<String, String>
         registrar.options = value
     }
 
+/**
+ * Controls for enabling incremental processing in KSP.
+ */
+var KotlinCompilation.kspIncremental: Boolean
+    get() = getKspRegistrar().incremental
+    set(value) {
+        val registrar = getKspRegistrar()
+        registrar.incremental = value
+    }
+
+/**
+ * Controls for enabling incremental processing logs in KSP.
+ */
+var KotlinCompilation.kspIncrementalLog: Boolean
+    get() = getKspRegistrar().incrementalLog
+    set(value) {
+        val registrar = getKspRegistrar()
+        registrar.incrementalLog = value
+    }
+
 private val KotlinCompilation.kspJavaSourceDir: File
     get() = kspSourcesDir.resolve("java")
 
@@ -100,6 +120,9 @@ private class KspCompileTestingComponentRegistrar(
 
     var options: MutableMap<String, String> = mutableMapOf()
 
+    var incremental: Boolean = false
+    var incrementalLog: Boolean = false
+
     override fun registerProjectComponents(project: MockProject, configuration: CompilerConfiguration) {
         if (processors.isEmpty()) {
             return
@@ -109,6 +132,9 @@ private class KspCompileTestingComponentRegistrar(
 
             this.processingOptions.putAll(compilation.kspArgs)
 
+            this.incremental = this@KspCompileTestingComponentRegistrar.incremental
+            this.incrementalLog = this@KspCompileTestingComponentRegistrar.incrementalLog
+
             this.cachesDir = compilation.kspCachesDir.also {
                 it.deleteRecursively()
                 it.mkdirs()

ksp/src/test/kotlin/com/tschuchort/compiletesting/KspTest.kt

@@ -130,6 +130,19 @@ class KspTest {
         }
     }
 
+    @Test
+    fun incremental() {
+        KotlinCompilation().apply {
+            // Disabled by default
+            assertThat(kspIncremental).isFalse()
+            assertThat(kspIncrementalLog).isFalse()
+            kspIncremental = true
+            assertThat(kspIncremental).isTrue()
+            kspIncrementalLog = true
+            assertThat(kspIncrementalLog).isTrue()
+        }
+    }
+
     @Test
     fun outputDirectoryContents() {
         val compilation = KotlinCompilation().apply {