Drop library, write custom diff function

app/model/commands/UpdateAtomCommand.scala

@@ -1,7 +1,6 @@
 package model.commands
 
 import java.util.Date
-import ai.x.diff.DiffShow
 import com.gu.atom.data.{AtomSerializer, VersionConflictError}
 import com.gu.contentatom.thrift.{Atom, ContentAtomEvent, EventType, ChangeRecord => ThriftChangeRecord}
 import com.gu.media.logging.Logging
@@ -124,22 +123,29 @@ case class UpdateAtomCommand(id: String, atom: MediaAtom, override val stores: D
 }
 
 object UpdateAtomCommand {
-  private val interestingFields = List("title", "category", "description", "duration", "source", "youtubeCategoryId", "license", "commentsEnabled", "channelId", "legallySensitive")
+  private val interestingFields = Seq[(String, MediaAtom => Option[Any])](
+    ("title", a => Some(a.title)),
+    ("category", a => Some(a.category)),
+    ("description", _.description),
+    ("duration", _.duration),
+    ("source", _.source),
+    ("youtubeCategoryId", _.youtubeCategoryId),
+    ("license", _.license),
+    ("commentsEnabled", _.composerCommentsEnabled),
+    ("channelId", _.channelId),
+    ("legallySensitive", _.legallySensitive)
+  )
 
   // We don't use HTTP patch so diffing has to be done manually
   def createDiffString(before: MediaAtom, after: MediaAtom): String = {
-    val fieldDiffs = DiffShow.diff[MediaAtom](before, after).string
-      .replaceAll("\\[*[0-9]+m", "") // Clean out the silly console coloring stuff
-      .split('\n')
-      .map(_.trim())
-      .filter(line => !line.contains("ERROR")) // More silly stuff from diffing library
-      .filter(line => interestingFields.exists(line.contains))
-      .mkString(", ")
-
-    if (fieldDiffs == "") { // There's a change, but in some field we're not interested in (or rather, unable to format nicely)
+    val changedFields = for {
+      (name, extractor) <- interestingFields
+      distinctValues = Seq(extractor(before), extractor(after)).distinct
+      if distinctValues.size > 1
+    } yield s"$name: ${distinctValues.map(_.getOrElse("[NONE]")).mkString(" -> ")}"
+
+    if (changedFields.isEmpty) { // There's a change, but in some field we're not interested in (or rather, unable to format nicely)
       "Updated atom fields"
-    } else {
-      s"Updated atom fields ($fieldDiffs)"
-    }
+    } else s"Updated atom fields (${changedFields.mkString(", ")})"
   }
 }

build.sbt

@@ -12,8 +12,6 @@ val scanamoVersion = "1.0.0-M9"
 
 val playJsonExtensionsVersion = "0.40.2"
 val okHttpVersion = "2.4.0"
-val diffVersion = "2.0.1"
-
 val capiAwsVersion = "0.5"
 
 val scalaTestVersion = "3.0.8"
@@ -135,7 +133,6 @@ lazy val app = (project in file("."))
     libraryDependencies ++= Seq(
       ehcache,
       "com.fasterxml.jackson.core" % "jackson-databind" % jacksonDatabindVersion,
-      "ai.x" %% "diff" % diffVersion,
       "com.amazonaws" % "aws-java-sdk-sts" % awsVersion,
       "com.amazonaws" % "aws-java-sdk-ec2" % awsVersion,
       "org.scalatestplus.play" %% "scalatestplus-play" % scalaTestPlusPlayVersion % "test",

test/model/commands/UpdateAtomCommandTest.scala

@@ -1,6 +1,7 @@
 package model.commands
 
 import com.gu.media.model.{Category, ContentChangeDetails, MediaAtom}
+import model.commands.UpdateAtomCommand.createDiffString
 import org.scalatest.{FunSuite, MustMatchers}
 
 class UpdateAtomCommandTest extends FunSuite with MustMatchers {
@@ -11,7 +12,7 @@ class UpdateAtomCommandTest extends FunSuite with MustMatchers {
     activeVersion = Some(1),
     title = "title",
     category = Category.News,
-    description = Some("description"),
+    description = Some("Example description"),
     duration = Some(1),
     source = Some("source"),
     posterImage = None,
@@ -30,7 +31,6 @@ class UpdateAtomCommandTest extends FunSuite with MustMatchers {
     keywords = List.empty,
     license = None,
     plutoData = None,
-    blockAds = false,
     expiryDate = None,
     legallySensitive = None,
     sensitive = None,
@@ -40,16 +40,18 @@ class UpdateAtomCommandTest extends FunSuite with MustMatchers {
   )
 
   test("Diff output when nothing changes") {
-    val str = UpdateAtomCommand.createDiffString(mediaAtomFixture, mediaAtomFixture)
-    println(str)
-    str must be(
-      """Updated atom fields (category = News$,, channelId = None,, description = Some( "description" ),, duration = Some( 1 ),, legallySensitive = None,, license = None,, source = Some( "source" ),, title = "title",, youtubeCategoryId = None,, youtubeTitle = "title")"""
-    )
+    createDiffString(mediaAtomFixture, mediaAtomFixture) must be("Updated atom fields")
   }
 
   test("Diff output when description changes") {
-    UpdateAtomCommand.createDiffString(mediaAtomFixture, mediaAtomFixture.copy(description = Some("New description"))) must be(
-      "Updated atom fields (MediaAtom( ..., description = Some( \u001B\"description\"\u001B -> \u001B\"New description\"\u001B ) ))"
+    createDiffString(mediaAtomFixture, mediaAtomFixture.copy(description = Some("New description"))) must be(
+      "Updated atom fields (description: Example description -> New description)"
+    )
+  }
+
+  test("Diff output when description is removed") {
+    createDiffString(mediaAtomFixture, mediaAtomFixture.copy(description = None)) must be(
+      "Updated atom fields (description: Example description -> [NONE])"
     )
   }
 }