diff --git a/src/applications/diffusion/query/rawdiff/DiffusionGitRawDiffQuery.php b/src/applications/diffusion/query/rawdiff/DiffusionGitRawDiffQuery.php
index 58cac2a28f..c408044bb6 100644
--- a/src/applications/diffusion/query/rawdiff/DiffusionGitRawDiffQuery.php
+++ b/src/applications/diffusion/query/rawdiff/DiffusionGitRawDiffQuery.php
@@ -35,13 +35,18 @@ final class DiffusionGitRawDiffQuery extends DiffusionRawDiffQuery {
     );
     $options = implode(' ', $options);
 
+    $against = $this->getAgainstCommit();
+    if ($against === null) {
+      $against = $commit.'^';
+    }
+
     // If there's no path, get the entire raw diff.
     $path = nonempty($drequest->getPath(), '.');
 
     $future = $repository->getLocalCommandFuture(
-      "diff %C %s^ %s -- %s",
+      "diff %C %s %s -- %s",
       $options,
-      $commit,
+      $against,
       $commit,
       $path);
 
diff --git a/src/applications/diffusion/query/rawdiff/DiffusionMercurialRawDiffQuery.php b/src/applications/diffusion/query/rawdiff/DiffusionMercurialRawDiffQuery.php
index 9551a1904c..cb03a7b9b9 100644
--- a/src/applications/diffusion/query/rawdiff/DiffusionMercurialRawDiffQuery.php
+++ b/src/applications/diffusion/query/rawdiff/DiffusionMercurialRawDiffQuery.php
@@ -27,9 +27,15 @@ final class DiffusionMercurialRawDiffQuery extends DiffusionRawDiffQuery {
     // If there's no path, get the entire raw diff.
     $path = nonempty($drequest->getPath(), '.');
 
+    $against = $this->getAgainstCommit();
+    if ($against === null) {
+      $against = $commit.'^';
+    }
+
     $future = $repository->getLocalCommandFuture(
-      'diff -U %d --git --change %s -- %s',
+      'diff -U %d --git --rev %s:%s -- %s',
       $this->getLinesOfContext(),
+      $against,
       $commit,
       $path);
 
diff --git a/src/applications/diffusion/query/rawdiff/DiffusionRawDiffQuery.php b/src/applications/diffusion/query/rawdiff/DiffusionRawDiffQuery.php
index d9eab546ea..eca89d6724 100644
--- a/src/applications/diffusion/query/rawdiff/DiffusionRawDiffQuery.php
+++ b/src/applications/diffusion/query/rawdiff/DiffusionRawDiffQuery.php
@@ -21,6 +21,7 @@ abstract class DiffusionRawDiffQuery extends DiffusionQuery {
   private $request;
   private $timeout;
   private $linesOfContext = 65535;
+  private $againstCommit;
 
   final public static function newFromDiffusionRequest(
     DiffusionRequest $request) {
@@ -49,4 +50,13 @@ abstract class DiffusionRawDiffQuery extends DiffusionQuery {
     return $this->linesOfContext;
   }
 
+  final public function setAgainstCommit($value) {
+    $this->againstCommit = $value;
+    return $this;
+  }
+
+  final public function getAgainstCommit() {
+    return $this->againstCommit;
+  }
+
 }
diff --git a/src/applications/diffusion/query/rawdiff/DiffusionSvnRawDiffQuery.php b/src/applications/diffusion/query/rawdiff/DiffusionSvnRawDiffQuery.php
index f3907ed1d8..8633ae3132 100644
--- a/src/applications/diffusion/query/rawdiff/DiffusionSvnRawDiffQuery.php
+++ b/src/applications/diffusion/query/rawdiff/DiffusionSvnRawDiffQuery.php
@@ -25,10 +25,16 @@ final class DiffusionSvnRawDiffQuery extends DiffusionRawDiffQuery {
     $commit = $drequest->getCommit();
     $arc_root = phutil_get_library_root('arcanist');
 
+    $against = $this->getAgainstCommit();
+    if ($against === null) {
+      $against = $commit - 1;
+    }
+
     $future = $repository->getRemoteCommandFuture(
-      'diff --diff-cmd %s -x -U%d -c %d %s%s@',
+      'diff --diff-cmd %s -x -U%d -r %d:%d %s%s@',
       $arc_root.'/../scripts/repository/binary_safe_diff.sh',
       $this->getLinesOfContext(),
+      $against,
       $commit,
       $repository->getRemoteURI(),
       $drequest->getPath());