[build-scripts] Don't use directory asset descriptor if jars in JarPackager#computeSourcesForModule (IJI-2700)

GitOrigin-RevId: 5e1887e37279704f8507637d81c4a3d3e81917ec

platform/build-scripts/src/org/jetbrains/intellij/build/impl/JarPackager.kt

@@ -296,7 +296,8 @@ class JarPackager private constructor(
     val packToDir = context.options.isUnpackedDist &&
                     !item.relativeOutputFile.contains('/') &&
                     (patchedContent.isEmpty() || (patchedContent.size == 1 && patchedContent.containsKey("META-INF/plugin.xml"))) &&
-                    extraExcludes.isEmpty()
+                    extraExcludes.isEmpty() &&
+                    !moduleOutDir.toString().endsWith(".jar")
 
     val outFile = outDir.resolve(item.relativeOutputFile)
     val asset = if (packToDir) {
@@ -934,6 +935,9 @@ private suspend fun buildAsset(
             SizeAndHash(size = 0, hash = computeHashForModuleOutput(it as DirSource))
           }
         }
+        else {
+          error("Unexpected source: $source")
+        }
       }
     }
     return BuildAssetResult(sourceToNativeFiles = emptyMap(), sourceToMetadata = sourceToMetadata)