dot export: fix file format (#289)

as discussed in joernio/joern#5158
I didn't get any feedback if this really solves their issue,
but this is certainly better than before

build.sbt

@@ -2,9 +2,10 @@ name := "flatgraph"
 ThisBuild / organization := "io.joern"
 ThisBuild / scalaVersion := scala3
 
-val slf4jVersion = "2.0.16"
 val scala3 = "3.5.2"
 val scala2_12 = "2.12.20"
+val slf4jVersion = "2.0.16"
+val commonsTextVersion = "1.13.0"
 
 /** Only the below listed projects are included in things like `sbt compile`.
   * We explicitly want to exclude `benchmarks` which requires qwiet.ai / shiftleft
@@ -51,6 +52,7 @@ lazy val formats = project
     name := "flatgraph-formats",
     libraryDependencies ++= Seq(
       "com.github.tototoshi" %% "scala-csv" % "2.0.0",
+      "org.apache.commons" % "commons-text" % commonsTextVersion,
       "org.scala-lang.modules" %% "scala-xml" % "2.3.0",
       "io.spray" %% "spray-json" % "1.3.6",
       "com.github.scopt" %% "scopt" % "4.1.0",
@@ -81,7 +83,7 @@ lazy val domainClassesGenerator_3 = project
     libraryDependencies ++= Seq(
       "org.slf4j" % "slf4j-simple" % slf4jVersion % Optional,
       "com.lihaoyi" %% "os-lib" % "0.9.1",
-      "org.apache.commons" % "commons-text" % "1.10.0",
+      "org.apache.commons" % "commons-text" % commonsTextVersion,
       "com.github.scopt" %% "scopt" % "4.1.0",
       ("org.scalameta" %% "scalafmt-dynamic" % "3.7.17").cross(CrossVersion.for3Use2_13),
     ),
@@ -97,7 +99,7 @@ lazy val domainClassesGenerator_2_12 = project
     libraryDependencies ++= Seq(
       "org.slf4j"% "slf4j-simple" % slf4jVersion % Optional,
       "com.lihaoyi" %% "os-lib" % "0.9.1",
-      "org.apache.commons" % "commons-text" % "1.12.0",
+      "org.apache.commons" % "commons-text" % commonsTextVersion,
       "com.github.scopt" %% "scopt" % "4.1.0",
       "org.scalameta" %% "scalafmt-dynamic" % "3.7.17",
     ),

formats/src/main/scala/flatgraph/formats/dot/DotExporter.scala

@@ -1,22 +1,40 @@
 package flatgraph.formats.dot
 
 import flatgraph.formats.{ExportResult, Exporter, iterableForList, resolveOutputFileSingle}
-import flatgraph.{Accessors, Edge, GNode, Graph, Schema}
+import flatgraph.{Accessors, Edge, GNode, Schema}
 
 import java.nio.file.{Files, Path}
-import scala.jdk.CollectionConverters.MapHasAsScala
+import org.apache.commons.text.StringEscapeUtils
+import org.apache.commons.text.translate.LookupTranslator
+
+import java.util.Collections
+import scala.jdk.CollectionConverters.MapHasAsJava
 import scala.util.Using
 
 /** Exports flatgraph to graphviz dot/gv file
   *
   * Note: GraphML doesn't natively support list property types, so we fake it by encoding it as a `;` delimited string. If you import this
   * into a different database, you'll need to parse that separately.
   *
+  * Export rules for dot format as per https: //github.com/joernio/joern/issues/5158 1) If the attribute value contains special characters
+  * such as spaces,<,>,=, etc., it must be enclosed in double quotation marks. Otherwise, it will cause syntax errors. 2) Graphviz requires
+  * that the node ID must be a valid identifier. If the node ID is a pure number (such as 120259084301), it needs to be enclosed in double
+  * quotation marks, otherwise it will be mistaken for an integer constant. 3) The attribute value contains special characters such as(such
+  * as CODE=""), which need to be enclosed in quotation marks or escaped in some cases. 4) In Graphviz's. dot file, it is best to use
+  * semicolons for each node definition, edge definition, and attribute definition; ending. Your file is missing semicolons.
+  *
   * https://en.wikipedia.org/wiki/DOT_(graph_description_language) https://www.graphviz.org/doc/info/lang.html
   * http://magjac.com/graphviz-visual-editor/ https://www.slideshare.net/albazo/graphiz-using-the-dot-language
   */
 object DotExporter extends Exporter {
   override def defaultFileExtension = "dot"
+  val EndOfLine                     = ';'
+
+  private val lookupMap = Map(
+    """\""" -> """\\""", // \ -> \\
+    "\""    -> """\""""  // " -> \"
+  )
+  val translator = new LookupTranslator(Collections.unmodifiableMap(lookupMap.asJava))
 
   override def runExport(schema: Schema, nodes: IterableOnce[GNode], edges: IterableOnce[Edge], outputFile: Path) = {
     val outFile              = resolveOutputFileSingle(outputFile, s"export.$defaultFileExtension")
@@ -34,31 +52,29 @@ object DotExporter extends Exporter {
         nodeCount += 1
         val line = new StringBuffer()
           .append("  ")
-          .append(node.id)
-          .append(s"[label=${node.label} ")
+          .append(s""""${node.id}" """)
+          .append(s"""[label="${node.label}" """)
           .append(
             Accessors
               .getNodeProperties(node)
               .iterator
               .map { case (key, value) =>
-                s"$key=${encodePropertyValue(value)}"
+                s"""$key="${encodePropertyValue(value)}""""
               }
               .mkString(" ")
           )
           .append("]")
+          .append(EndOfLine)
         writeLine(line.toString)
       }
 
       edges.iterator.foreach { edge =>
         edgeCount += 1
+        val propertyMaybe = Option(edge.property).map(property => s"""property="${encodePropertyValue(property)}"""").getOrElse("")
         val line = new StringBuffer()
-          .append(s"  ${edge.src.id()} -> ${edge.dst.id()} ")
-          .append(s"[label=${edge.label} ")
-
-        if (edge.property != null)
-          line.append(s"property=${encodePropertyValue(edge.property)}")
-
-        line.append("]")
+          .append(s"""  "${edge.src.id()}" -> "${edge.dst.id()}"""")
+          .append(s""" [label="${edge.label}" $propertyMaybe]""")
+          .append(EndOfLine)
         writeLine(line.toString)
       }
 
@@ -71,13 +87,9 @@ object DotExporter extends Exporter {
   private def encodePropertyValue(value: Any): String = {
     value match {
       case value: String =>
-        val escaped = value
-          .replace("""\""", """\\""") // escape escape chars - this should come first
-          .replace("\"", "\\\"")      // escape double quotes, because we use them to enclose strings
-        s"\"$escaped\""
+        StringEscapeUtils.builder(translator).escape(value).toString
       case list if iterableForList.isDefinedAt(list) =>
-        val values = iterableForList(list).mkString(";")
-        s"\"$values\""
+        iterableForList(list).map(encodePropertyValue).mkString(";")
       case value => value.toString
     }
   }

tests/src/test/scala/flatgraph/formats/dot/DotExporterTests.scala

@@ -0,0 +1,56 @@
+package flatgraph.formats.dot
+
+import better.files.*
+import flatgraph.*
+import org.scalatest.matchers.should.Matchers.*
+import org.scalatest.wordspec.AnyWordSpec
+import testdomains.generic.GenericDomain
+import testdomains.generic.edges.ConnectedTo
+import testdomains.generic.nodes.NewNodeA
+
+class DotExporterTests extends AnyWordSpec {
+
+  "Exporter should export valid dot" in {
+    val graph = GenericDomain.empty.graph
+    val node1 = NewNodeA()
+      .stringMandatory("regular string")
+      .stringOptional("""<escapeMe1> [escapeMe2] escape=Me3 escape"Me4 escape\Me5 """)
+      .stringList(Seq("one", "two"))
+    val node2 = NewNodeA().intMandatory(1).intOptional(2).intList(Seq(10, 11))
+
+    DiffGraphApplier.applyDiff(
+      graph,
+      GenericDomain.newDiffGraphBuilder
+        .addEdge(node1, node2, ConnectedTo.Label, "edge property")
+    )
+
+    File.usingTemporaryDirectory(getClass.getName) { exportRootDirectory =>
+      val exportResult = DotExporter.runExport(graph, exportRootDirectory.pathAsString)
+      exportResult.nodeCount shouldBe 2
+      exportResult.edgeCount shouldBe 1
+      val Seq(exportedFile) = exportResult.files
+
+      val result = better.files.File(exportedFile).contentAsString.trim
+
+      /* Export rules for dot format as per https: //github.com/joernio/joern/issues/5158 :
+       * 1) If the attribute value contains special characters such as spaces,<,>,=, etc., it must be enclosed in double quotation marks.
+       * Otherwise, it will cause syntax errors.
+       * 2) Graphviz requires that the node ID must be a valid identifier. If the node ID is a pure number (such as 120259084301),
+       * it needs to be enclosed in double quotation marks, otherwise it will be mistaken for an integer constant.
+       * 3) The attribute value contains special characters such as(such as CODE=""), which need to be enclosed in quotation marks or escaped in some cases.
+       * 4) In Graphviz's. dot file, it is best to use semicolons for each node definition, edge definition, and attribute definition; ending. Your file is missing semicolons.
+       */
+
+      withClue(s"actual result was: `$result`") {
+        result.trim shouldBe
+          """digraph {
+          |  "0" [label="node_a" int_mandatory="42" string_list="one;two" string_mandatory="regular string" string_optional="<escapeMe1> [escapeMe2] escape=Me3 escape\"Me4 escape\\Me5 "];
+          |  "1" [label="node_a" int_list="10;11" int_mandatory="1" int_optional="2" string_mandatory="<empty>"];
+          |  "0" -> "1" [label="connected_to" property="edge property"];
+          |}
+          |""".stripMargin.trim
+      }
+    }
+  }
+
+}