[Commonizer] Allow propagation of leaf targets

^KT-46248 Verification Pending

native/commonizer/src/org/jetbrains/kotlin/commonizer/CommonizerParameters.kt

@@ -22,7 +22,7 @@ class CommonizerParameters(
 
 fun CommonizerParameters.getCommonModuleNames(): Set<String> {
     val supportedTargets = targetProviders.filterNonNull()
-    if (supportedTargets.size < 2) return emptySet() // too few targets
+    if (supportedTargets.size == 0) return emptySet() // Nothing to do
 
     val allModuleNames: List<Set<String>> = supportedTargets.toList().map { targetProvider ->
         targetProvider.modulesProvider.loadModuleInfos().mapTo(HashSet()) { it.name }

native/commonizer/src/org/jetbrains/kotlin/commonizer/facade.kt

@@ -82,9 +82,6 @@ private fun merge(
     /* Nothing to merge */
     if (availableTrees.size == 0) return null
 
-    /* No propagation from leaves */
-    if (availableTrees.size == 1 && availableTrees.targets.single() is LeafCommonizerTarget) return null
-
     return mergeCirTree(storageManager, classifiers, availableTrees)
 }
 

native/commonizer/tests/org/jetbrains/kotlin/commonizer/CommonizerFacadeTest.kt

@@ -24,13 +24,6 @@ class CommonizerFacadeTest {
         emptyMap()
     )
 
-    @Test
-    fun nothingToCommonize1() = doTestNothingToCommonize(
-        mapOf(
-            "target1" to listOf("foo")
-        )
-    )
-
     @Test
     fun commonized1() = doTestSuccessfulCommonization(
         mapOf(
@@ -47,6 +40,13 @@ class CommonizerFacadeTest {
         )
     )
 
+    @Test
+    fun commonized3() = doTestSuccessfulCommonization(
+        mapOf(
+            "target1" to listOf("foo")
+        )
+    )
+
     @Test
     fun commonizedWithDifferentModules() = doTestNothingToCommonize(
         mapOf(