diff --git a/java/com/google/gerrit/server/change/FileInfoJsonNewImpl.java b/java/com/google/gerrit/server/change/FileInfoJsonNewImpl.java
index ed046826..0d3dcff 100644
--- a/java/com/google/gerrit/server/change/FileInfoJsonNewImpl.java
+++ b/java/com/google/gerrit/server/change/FileInfoJsonNewImpl.java
@@ -89,8 +89,8 @@
       FileDiffOutput fileDiff = fileDiffs.get(path);
       FileInfo fileInfo = new FileInfo();
       fileInfo.status =
-          fileDiff.changeType().get() != Patch.ChangeType.MODIFIED
-              ? fileDiff.changeType().get().getCode()
+          fileDiff.changeType() != Patch.ChangeType.MODIFIED
+              ? fileDiff.changeType().getCode()
               : null;
       fileInfo.oldPath = fileDiff.oldPath().orElse(null);
       fileInfo.sizeDelta = fileDiff.sizeDelta();
diff --git a/java/com/google/gerrit/server/patch/DiffOperations.java b/java/com/google/gerrit/server/patch/DiffOperations.java
index 1d8438e..87a43c0 100644
--- a/java/com/google/gerrit/server/patch/DiffOperations.java
+++ b/java/com/google/gerrit/server/patch/DiffOperations.java
@@ -17,6 +17,7 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Patch;
 import com.google.gerrit.entities.Project;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo;
 import com.google.gerrit.server.patch.filediff.FileDiffOutput;
 import java.util.Map;
 import org.eclipse.jgit.lib.ObjectId;
@@ -80,12 +81,17 @@
    * @param parentNum integer specifying which parent to use as base. If null, the only parent will
    *     be used or the auto-merge if {@code newCommit} is a merge commit.
    * @param fileName the file name for which the diff should be evaluated.
+   * @param whitespace preference controlling whitespace effect in diff computation.
    * @return the diff for the single file between the two commits.
    * @throws DiffNotAvailableException if an internal error occurred in Git while evaluating the
    *     diff, or if an exception happened while parsing the base commit.
    */
   FileDiffOutput getModifiedFileAgainstParent(
-      Project.NameKey project, ObjectId newCommit, @Nullable Integer parentNum, String fileName)
+      Project.NameKey project,
+      ObjectId newCommit,
+      @Nullable Integer parentNum,
+      String fileName,
+      @Nullable DiffPreferencesInfo.Whitespace whitespace)
       throws DiffNotAvailableException;
 
   /**
@@ -96,11 +102,16 @@
    * @param oldCommit 20 bytes SHA-1 of the old commit used in the diff.
    * @param newCommit 20 bytes SHA-1 of the new commit used in the diff.
    * @param fileName the file name for which the diff should be evaluated.
+   * @param whitespace preference controlling whitespace effect in diff computation.
    * @return the diff for the single file between the two commits.
    * @throws DiffNotAvailableException if an internal error occurred in Git while evaluating the
    *     diff.
    */
   FileDiffOutput getModifiedFile(
-      Project.NameKey project, ObjectId oldCommit, ObjectId newCommit, String fileName)
+      Project.NameKey project,
+      ObjectId oldCommit,
+      ObjectId newCommit,
+      String fileName,
+      @Nullable DiffPreferencesInfo.Whitespace whitespace)
       throws DiffNotAvailableException;
 }
diff --git a/java/com/google/gerrit/server/patch/DiffOperationsImpl.java b/java/com/google/gerrit/server/patch/DiffOperationsImpl.java
index 2d98d42..45ba789 100644
--- a/java/com/google/gerrit/server/patch/DiffOperationsImpl.java
+++ b/java/com/google/gerrit/server/patch/DiffOperationsImpl.java
@@ -25,6 +25,7 @@
 import com.google.gerrit.entities.Patch;
 import com.google.gerrit.entities.Patch.ChangeType;
 import com.google.gerrit.entities.Project;
+import com.google.gerrit.extensions.client.DiffPreferencesInfo;
 import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
 import com.google.gerrit.server.cache.CacheModule;
 import com.google.gerrit.server.patch.diff.ModifiedFilesCache;
@@ -55,6 +56,7 @@
 
   private static final int RENAME_SCORE = 60;
   private static final DiffAlgorithm DEFAULT_DIFF_ALGORITHM = DiffAlgorithm.HISTOGRAM;
+  private static final Whitespace DEFAULT_WHITESPACE = Whitespace.IGNORE_NONE;
 
   private final ModifiedFilesCache modifiedFilesCache;
   private final FileDiffCache fileDiffCache;
@@ -112,12 +114,16 @@
 
   @Override
   public FileDiffOutput getModifiedFileAgainstParent(
-      Project.NameKey project, ObjectId newCommit, @Nullable Integer parent, String fileName)
+      Project.NameKey project,
+      ObjectId newCommit,
+      @Nullable Integer parent,
+      String fileName,
+      @Nullable DiffPreferencesInfo.Whitespace whitespace)
       throws DiffNotAvailableException {
     try {
       DiffParameters diffParams = computeDiffParameters(project, newCommit, parent);
       FileDiffCacheKey key =
-          createFileDiffCacheKey(project, diffParams.baseCommit(), newCommit, fileName);
+          createFileDiffCacheKey(project, diffParams.baseCommit(), newCommit, fileName, whitespace);
       return getModifiedFilesForKeys(ImmutableList.of(key)).get(fileName);
     } catch (IOException e) {
       throw new DiffNotAvailableException(
@@ -127,9 +133,14 @@
 
   @Override
   public FileDiffOutput getModifiedFile(
-      Project.NameKey project, ObjectId oldCommit, ObjectId newCommit, String fileName)
+      Project.NameKey project,
+      ObjectId oldCommit,
+      ObjectId newCommit,
+      String fileName,
+      @Nullable DiffPreferencesInfo.Whitespace whitespace)
       throws DiffNotAvailableException {
-    FileDiffCacheKey key = createFileDiffCacheKey(project, oldCommit, newCommit, fileName);
+    FileDiffCacheKey key =
+        createFileDiffCacheKey(project, oldCommit, newCommit, fileName, whitespace);
     return getModifiedFilesForKeys(ImmutableList.of(key)).get(fileName);
   }
 
@@ -144,10 +155,14 @@
           modifiedFilesCache.get(createModifiedFilesKey(project, oldCommit, newCommit));
 
       List<FileDiffCacheKey> fileCacheKeys = new ArrayList<>();
-      fileCacheKeys.add(createFileDiffCacheKey(project, oldCommit, newCommit, COMMIT_MSG));
+      fileCacheKeys.add(
+          createFileDiffCacheKey(
+              project, oldCommit, newCommit, COMMIT_MSG, /* whitespace= */ null));
 
       if (cmp.isAgainstAutoMerge() || isMergeAgainstParent(cmp, project, newCommit)) {
-        fileCacheKeys.add(createFileDiffCacheKey(project, oldCommit, newCommit, MERGE_LIST));
+        fileCacheKeys.add(
+            createFileDiffCacheKey(
+                project, oldCommit, newCommit, MERGE_LIST, /*whitespace = */ null));
       }
 
       if (diffParams.skipFiles() == null) {
@@ -160,7 +175,8 @@
                         newCommit,
                         entity.newPath().isPresent()
                             ? entity.newPath().get()
-                            : entity.oldPath().get()))
+                            : entity.oldPath().get(),
+                        /* whitespace= */ null))
             .forEach(fileCacheKeys::add);
       }
       return getModifiedFilesForKeys(fileCacheKeys);
@@ -178,7 +194,7 @@
       if (fileDiffOutput.isEmpty() || allDueToRebase(fileDiffOutput)) {
         continue;
       }
-      if (fileDiffOutput.changeType().get() == Patch.ChangeType.DELETED) {
+      if (fileDiffOutput.changeType() == ChangeType.DELETED) {
         files.put(fileDiffOutput.oldPath().get(), fileDiffOutput);
       } else {
         files.put(fileDiffOutput.newPath().get(), fileDiffOutput);
@@ -189,8 +205,8 @@
 
   private static boolean allDueToRebase(FileDiffOutput fileDiffOutput) {
     return fileDiffOutput.allEditsDueToRebase()
-        && (!(fileDiffOutput.changeType().get() == ChangeType.RENAMED
-            || fileDiffOutput.changeType().get() == ChangeType.COPIED));
+        && (!(fileDiffOutput.changeType() == ChangeType.RENAMED
+            || fileDiffOutput.changeType() == ChangeType.COPIED));
   }
 
   private boolean isMergeAgainstParent(ComparisonType cmp, Project.NameKey project, ObjectId commit)
@@ -209,7 +225,12 @@
   }
 
   private static FileDiffCacheKey createFileDiffCacheKey(
-      Project.NameKey project, ObjectId aCommit, ObjectId bCommit, String newPath) {
+      Project.NameKey project,
+      ObjectId aCommit,
+      ObjectId bCommit,
+      String newPath,
+      @Nullable Whitespace whitespace) {
+    whitespace = whitespace == null ? DEFAULT_WHITESPACE : whitespace;
     return FileDiffCacheKey.builder()
         .project(project)
         .oldCommit(aCommit)
@@ -217,7 +238,7 @@
         .newFilePath(newPath)
         .renameScore(RENAME_SCORE)
         .diffAlgorithm(DEFAULT_DIFF_ALGORITHM)
-        .whitespace(Whitespace.IGNORE_NONE)
+        .whitespace(whitespace)
         .build();
   }
 
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
index d945da3..fb2aa3d 100644
--- a/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffCacheImpl.java
@@ -288,7 +288,7 @@
       return FileDiffOutput.builder()
           .oldPath(FileHeaderUtil.getOldPath(fileHeader))
           .newPath(FileHeaderUtil.getNewPath(fileHeader))
-          .changeType(Optional.of(changeType))
+          .changeType(changeType)
           .patchType(Optional.of(FileHeaderUtil.getPatchType(fileHeader)))
           .headerLines(FileHeaderUtil.getHeaderLines(fileHeader))
           .edits(
diff --git a/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java b/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
index 46ce28b..3348033 100644
--- a/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
+++ b/java/com/google/gerrit/server/patch/filediff/FileDiffOutput.java
@@ -47,7 +47,7 @@
   public abstract Optional<String> newPath();
 
   /** The change type of the underlying file, e.g. added, deleted, renamed, etc... */
-  public abstract Optional<Patch.ChangeType> changeType();
+  public abstract Patch.ChangeType changeType();
 
   /** The patch type of the underlying file, e.g. unified, binary , etc... */
   public abstract Optional<Patch.PatchType> patchType();
@@ -95,10 +95,11 @@
   }
 
   /** Returns an entity representing an unchanged file between two commits. */
-  static FileDiffOutput empty(String filePath) {
+  public static FileDiffOutput empty(String filePath) {
     return builder()
         .oldPath(Optional.empty())
         .newPath(Optional.of(filePath))
+        .changeType(ChangeType.MODIFIED)
         .headerLines(ImmutableList.of())
         .edits(ImmutableList.of())
         .size(0)
@@ -123,9 +124,7 @@
     if (newPath().isPresent()) {
       result += stringSize(newPath().get());
     }
-    if (changeType().isPresent()) {
-      result += 4;
-    }
+    result += 4; // changeType
     if (patchType().isPresent()) {
       result += 4;
     }
@@ -145,7 +144,7 @@
 
     public abstract Builder newPath(Optional<String> value);
 
-    public abstract Builder changeType(Optional<ChangeType> value);
+    public abstract Builder changeType(ChangeType value);
 
     public abstract Builder patchType(Optional<PatchType> value);
 
@@ -169,9 +168,6 @@
     private static final FieldDescriptor NEW_PATH_DESCRIPTOR =
         FileDiffOutputProto.getDescriptor().findFieldByNumber(2);
 
-    private static final FieldDescriptor CHANGE_TYPE_DESCRIPTOR =
-        FileDiffOutputProto.getDescriptor().findFieldByNumber(3);
-
     private static final FieldDescriptor PATCH_TYPE_DESCRIPTOR =
         FileDiffOutputProto.getDescriptor().findFieldByNumber(4);
 
@@ -182,6 +178,7 @@
               .setSize(fileDiff.size())
               .setSizeDelta(fileDiff.sizeDelta())
               .addAllHeaderLines(fileDiff.headerLines())
+              .setChangeType(fileDiff.changeType().name())
               .addAllEdits(
                   fileDiff.edits().stream()
                       .map(
@@ -206,10 +203,6 @@
         builder.setNewPath(fileDiff.newPath().get());
       }
 
-      if (fileDiff.changeType().isPresent()) {
-        builder.setChangeType(fileDiff.changeType().get().name());
-      }
-
       if (fileDiff.patchType().isPresent()) {
         builder.setPatchType(fileDiff.patchType().get().name());
       }
@@ -225,6 +218,7 @@
           .size(proto.getSize())
           .sizeDelta(proto.getSizeDelta())
           .headerLines(proto.getHeaderLinesList().stream().collect(ImmutableList.toImmutableList()))
+          .changeType(ChangeType.valueOf(proto.getChangeType()))
           .edits(
               proto.getEditsList().stream()
                   .map(
@@ -244,9 +238,6 @@
       if (proto.hasField(NEW_PATH_DESCRIPTOR)) {
         builder.newPath(Optional.of(proto.getNewPath()));
       }
-      if (proto.hasField(CHANGE_TYPE_DESCRIPTOR)) {
-        builder.changeType(Optional.of(Patch.ChangeType.valueOf(proto.getChangeType())));
-      }
       if (proto.hasField(PATCH_TYPE_DESCRIPTOR)) {
         builder.patchType(Optional.of(Patch.PatchType.valueOf(proto.getPatchType())));
       }
diff --git a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java
index 81c0e5d..a01d447 100644
--- a/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java
+++ b/java/com/google/gerrit/server/patch/gitfilediff/GitFileDiff.java
@@ -77,7 +77,7 @@
         .fileHeader(FileHeaderUtil.toString(fileHeader))
         .oldPath(FileHeaderUtil.getOldPath(fileHeader))
         .newPath(FileHeaderUtil.getNewPath(fileHeader))
-        .changeType(Optional.of(FileHeaderUtil.getChangeType(fileHeader)))
+        .changeType(FileHeaderUtil.getChangeType(fileHeader))
         .patchType(Optional.of(FileHeaderUtil.getPatchType(fileHeader)))
         .oldMode(Optional.of(mapFileMode(diffEntry.getOldMode())))
         .newMode(Optional.of(mapFileMode(diffEntry.getNewMode())))
@@ -96,6 +96,7 @@
         .oldId(oldId)
         .newId(newId)
         .newPath(Optional.of(newFilePath))
+        .changeType(ChangeType.MODIFIED)
         .edits(ImmutableList.of())
         .fileHeader("")
         .build();
@@ -126,7 +127,7 @@
   public abstract Optional<Patch.FileMode> newMode();
 
   /** The change type associated with the file. */
-  public abstract Optional<ChangeType> changeType();
+  public abstract ChangeType changeType();
 
   /** The patch type associated with the file. */
   public abstract Optional<PatchType> patchType();
@@ -150,9 +151,7 @@
     if (newPath().isPresent()) {
       result += stringSize(newPath().get());
     }
-    if (changeType().isPresent()) {
-      result += 4;
-    }
+    result += 4;
     if (patchType().isPresent()) {
       result += 4;
     }
@@ -188,7 +187,7 @@
 
     public abstract Builder newMode(Optional<Patch.FileMode> value);
 
-    public abstract Builder changeType(Optional<ChangeType> value);
+    public abstract Builder changeType(ChangeType value);
 
     public abstract Builder patchType(Optional<PatchType> value);
 
@@ -223,7 +222,8 @@
           GitFileDiffProto.newBuilder()
               .setFileHeader(gitFileDiff.fileHeader())
               .setOldId(idConverter.toByteString(gitFileDiff.oldId().toObjectId()))
-              .setNewId(idConverter.toByteString(gitFileDiff.newId().toObjectId()));
+              .setNewId(idConverter.toByteString(gitFileDiff.newId().toObjectId()))
+              .setChangeType(gitFileDiff.changeType().name());
       gitFileDiff
           .edits()
           .forEach(
@@ -246,9 +246,6 @@
       if (gitFileDiff.newMode().isPresent()) {
         builder.setNewMode(gitFileDiff.newMode().get().name());
       }
-      if (gitFileDiff.changeType().isPresent()) {
-        builder.setChangeType(gitFileDiff.changeType().get().name());
-      }
       if (gitFileDiff.patchType().isPresent()) {
         builder.setPatchType(gitFileDiff.patchType().get().name());
       }
@@ -267,7 +264,8 @@
                   .collect(toImmutableList()))
           .fileHeader(proto.getFileHeader())
           .oldId(AbbreviatedObjectId.fromObjectId(idConverter.fromByteString(proto.getOldId())))
-          .newId(AbbreviatedObjectId.fromObjectId(idConverter.fromByteString(proto.getNewId())));
+          .newId(AbbreviatedObjectId.fromObjectId(idConverter.fromByteString(proto.getNewId())))
+          .changeType(ChangeType.valueOf(proto.getChangeType()));
 
       if (proto.hasField(OLD_PATH_DESCRIPTOR)) {
         builder.oldPath(Optional.of(proto.getOldPath()));
@@ -281,9 +279,6 @@
       if (proto.hasField(NEW_MODE_DESCRIPTOR)) {
         builder.newMode(Optional.of(Patch.FileMode.valueOf(proto.getNewMode())));
       }
-      if (proto.hasField(CHANGE_TYPE_DESCRIPTOR)) {
-        builder.changeType(Optional.of(Patch.ChangeType.valueOf(proto.getChangeType())));
-      }
       if (proto.hasField(PATCH_TYPE_DESCRIPTOR)) {
         builder.patchType(Optional.of(Patch.PatchType.valueOf(proto.getPatchType())));
       }
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java
index 4307954..44ea55a 100644
--- a/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/FileDiffOutputSerializerTest.java
@@ -37,7 +37,7 @@
         FileDiffOutput.builder()
             .oldPath(Optional.of("old_file_path.txt"))
             .newPath(Optional.empty())
-            .changeType(Optional.of(ChangeType.DELETED))
+            .changeType(ChangeType.DELETED)
             .patchType(Optional.of(PatchType.UNIFIED))
             .size(23)
             .sizeDelta(10)
diff --git a/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java b/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java
index 8030818..93441a4 100644
--- a/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java
+++ b/javatests/com/google/gerrit/server/cache/serialize/entities/GitFileDiffSerializerTest.java
@@ -47,7 +47,7 @@
             .newPath(Optional.empty())
             .oldId(AbbreviatedObjectId.fromObjectId(OLD_ID))
             .newId(AbbreviatedObjectId.fromObjectId(NEW_ID))
-            .changeType(Optional.of(ChangeType.DELETED))
+            .changeType(ChangeType.DELETED)
             .patchType(Optional.of(PatchType.UNIFIED))
             .oldMode(Optional.of(FileMode.REGULAR_FILE))
             .newMode(Optional.of(FileMode.REGULAR_FILE))