Preserve the original source-level formatting when possible after exp…

…loding imports (#280)

input/src/main/scala/fix/ExplodeImportsFormatPreserving.scala

@@ -0,0 +1,12 @@
+/*
+rules = [OrganizeImports]
+OrganizeImports.removeUnused = false
+OrganizeImports.groupedImports = Explode
+ */
+
+package fix
+
+import fix.ExplodeImports.FormatPreserving.g1.{ a, b }
+import fix.ExplodeImports.FormatPreserving.g2.{ c => C, _ }
+
+object ExplodeImportsFormatPreserving

output/src/main/scala/fix/ExplodeImportsFormatPreserving.scala

@@ -0,0 +1,7 @@
+package fix
+
+import fix.ExplodeImports.FormatPreserving.g1.a
+import fix.ExplodeImports.FormatPreserving.g1.b
+import fix.ExplodeImports.FormatPreserving.g2.{ c => C, _ }
+
+object ExplodeImportsFormatPreserving

rules/src/main/scala/fix/OrganizeImports.scala

@@ -499,17 +499,7 @@ class OrganizeImports(config: OrganizeImportsConfig) extends SemanticRule("Organ
           }
         }
 
-        // Issue #127: After merging imports within an importer group, checks whether there are any
-        // input importers left untouched. For those importers, returns the original importer
-        // instance to preserve the original source level formatting.
-        locally {
-          val importerSyntaxMap = group.map { i => i.copy().syntax -> i }.toMap
-
-          newImporteeListsWithGivens filter (_.nonEmpty) map { importees =>
-            val newImporter = Importer(ref, importees)
-            importerSyntaxMap.getOrElse(newImporter.syntax, newImporter)
-          }
-        }
+        preserveOriginalImportersFormatting(group, newImporteeListsWithGivens, ref)
     }
 
   private def sortImportersSymbolsFirst(importers: Seq[Importer]): Seq[Importer] =
@@ -786,8 +776,10 @@ object OrganizeImports {
         // source level formatting.
         importer :: Nil
 
-      case Importer(ref, Importees(names, renames, unimports, givens, givenAll, wildcard))
-          if givenAll.isDefined || wildcard.isDefined =>
+      case importer @ Importer(
+            ref,
+            Importees(names, renames, unimports, givens, givenAll, wildcard)
+          ) if givenAll.isDefined || wildcard.isDefined =>
         // When a wildcard exists, all renames, unimports, and the wildcard must appear in the same
         // importer, e.g.:
         //
@@ -799,12 +791,30 @@ object OrganizeImports {
         //   import p.E
         val importeesList =
           (names ++ givens).map(_ :: Nil) :+ (renames ++ unimports ++ wildcard ++ givenAll)
-        importeesList filter (_.nonEmpty) map (Importer(ref, _))
+        preserveOriginalImportersFormatting(Seq(importer), importeesList, ref)
 
       case importer =>
         importer.importees map (i => importer.copy(importees = i :: Nil))
     }
 
+  /**
+   * Issue #127: After merging or exploding imports, checks whether there are any input importers
+   * left untouched. For those importers, returns the original importer instance to preserve the
+   * original source level formatting.
+   */
+  private def preserveOriginalImportersFormatting(
+    importers: Seq[Importer],
+    newImporteeLists: Seq[List[Importee]],
+    newImporterRef: Term.Ref
+  ) = {
+    val importerSyntaxMap = importers.map { i => i.copy().syntax -> i }.toMap
+
+    newImporteeLists filter (_.nonEmpty) map { importees =>
+      val newImporter = Importer(newImporterRef, importees)
+      importerSyntaxMap.getOrElse(newImporter.syntax, newImporter)
+    }
+  }
+
   /**
    * Categorizes a list of `Importee`s into the following four groups:
    *

shared/src/main/scala/fix/ExplodeImports.scala

@@ -0,0 +1,60 @@
+package fix
+
+object ExplodeImports {
+  object Wildcard1 {
+    object a
+    object b
+    object c
+    object d
+  }
+
+  object Wildcard2 {
+    object a
+    object b
+  }
+
+  object Unimport1 {
+    object a
+    object b
+    object c
+    object d
+  }
+
+  object Unimport2 {
+    object a
+    object b
+    object c
+    object d
+  }
+
+  object Rename1 {
+    object a
+    object b
+    object c
+    object d
+  }
+
+  object Rename2 {
+    object a
+    object b
+    object c
+  }
+
+  object Dedup {
+    object a
+    object b
+    object c
+  }
+
+  object FormatPreserving {
+    object g1 {
+      object a
+      object b
+    }
+
+    object g2 {
+      object c
+      object d
+    }
+  }
+}