Remove logic around loadInverse (#1668)

Author: ursachec

codepropertygraph/src/main/scala/io/shiftleft/codepropertygraph/cpgloading/CpgLoader.scala

@@ -54,9 +54,6 @@ object CpgLoader {
   def addOverlays(overlayFilenames: Seq[String], cpg: Cpg): Unit =
     new CpgLoader().addOverlays(overlayFilenames, cpg)
 
-  def addDiffGraphs(diffGraphFilenames: Seq[String], cpg: Cpg): Unit =
-    new CpgLoader().addDiffGraphs(diffGraphFilenames, cpg)
-
   /** Determine whether the CPG is a legacy (proto) CPG
     *
     * @param filename
@@ -107,10 +104,4 @@ private class CpgLoader {
     }
   }
 
-  def addDiffGraphs(diffGraphFilenames: Seq[String], cpg: Cpg): Unit = {
-    diffGraphFilenames.foreach { filename =>
-      CpgOverlayLoader.loadInverse(filename, cpg)
-    }
-  }
-
 }

codepropertygraph/src/main/scala/io/shiftleft/codepropertygraph/cpgloading/CpgOverlayLoader.scala

@@ -32,21 +32,6 @@ private[cpgloading] object CpgOverlayLoader {
       .get
   }
 
-  def loadInverse(filename: String, baseCpg: Cpg): Unit = {
-    ProtoCpgLoader
-      .loadDiffGraphs(filename)
-      .map { diffGraphs =>
-        diffGraphs.toList.reverse.map { diffGraph =>
-          DiffGraph.Applier.applyDiff(DiffGraph.fromProto(diffGraph, baseCpg), baseCpg)
-        }
-      }
-      .recover { case e: IOException =>
-        logger.error("Failed to load overlay from " + filename, e)
-        Nil
-      }
-      .get
-  }
-
 }
 
 /** Component to merge CPG overlay into existing graph