diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -650,6 +650,7 @@
     'DiffusionHovercardEngineExtension' => 'applications/diffusion/engineextension/DiffusionHovercardEngineExtension.php',
     'DiffusionInlineCommentController' => 'applications/diffusion/controller/DiffusionInlineCommentController.php',
     'DiffusionInlineCommentPreviewController' => 'applications/diffusion/controller/DiffusionInlineCommentPreviewController.php',
+    'DiffusionInternalGitRawDiffQueryConduitAPIMethod' => 'applications/diffusion/conduit/DiffusionInternalGitRawDiffQueryConduitAPIMethod.php',
     'DiffusionLastModifiedController' => 'applications/diffusion/controller/DiffusionLastModifiedController.php',
     'DiffusionLastModifiedQueryConduitAPIMethod' => 'applications/diffusion/conduit/DiffusionLastModifiedQueryConduitAPIMethod.php',
     'DiffusionLintController' => 'applications/diffusion/controller/DiffusionLintController.php',
@@ -4836,6 +4837,7 @@
     'DiffusionHovercardEngineExtension' => 'PhabricatorHovercardEngineExtension',
     'DiffusionInlineCommentController' => 'PhabricatorInlineCommentController',
     'DiffusionInlineCommentPreviewController' => 'PhabricatorInlineCommentPreviewController',
+    'DiffusionInternalGitRawDiffQueryConduitAPIMethod' => 'DiffusionQueryConduitAPIMethod',
     'DiffusionLastModifiedController' => 'DiffusionController',
     'DiffusionLastModifiedQueryConduitAPIMethod' => 'DiffusionQueryConduitAPIMethod',
     'DiffusionLintController' => 'DiffusionController',
diff --git a/src/applications/conduit/method/ConduitAPIMethod.php b/src/applications/conduit/method/ConduitAPIMethod.php
--- a/src/applications/conduit/method/ConduitAPIMethod.php
+++ b/src/applications/conduit/method/ConduitAPIMethod.php
@@ -52,6 +52,9 @@
 
   abstract protected function execute(ConduitAPIRequest $request);
 
+  public function isInternalAPI() {
+    return false;
+  }
 
   public function getParamTypes() {
     $types = $this->defineParamTypes();
diff --git a/src/applications/conduit/query/PhabricatorConduitMethodQuery.php b/src/applications/conduit/query/PhabricatorConduitMethodQuery.php
--- a/src/applications/conduit/query/PhabricatorConduitMethodQuery.php
+++ b/src/applications/conduit/query/PhabricatorConduitMethodQuery.php
@@ -9,6 +9,7 @@
   private $applicationNames;
   private $nameContains;
   private $methods;
+  private $isInternal;
 
   public function withMethods(array $methods) {
     $this->methods = $methods;
@@ -40,6 +41,11 @@
     return $this;
   }
 
+  public function withIsInternal($is_internal) {
+    $this->isInternal = $is_internal;
+    return $this;
+  }
+
   protected function loadPage() {
     $methods = $this->getAllMethods();
     $methods = $this->filterMethods($methods);
@@ -112,6 +118,14 @@
       }
     }
 
+    if ($this->isInternal !== null) {
+      foreach ($methods as $key => $method) {
+        if ($method->isInternalAPI() !== $this->isInternal) {
+          unset($methods[$key]);
+        }
+      }
+    }
+
     return $methods;
   }
 
diff --git a/src/applications/conduit/query/PhabricatorConduitSearchEngine.php b/src/applications/conduit/query/PhabricatorConduitSearchEngine.php
--- a/src/applications/conduit/query/PhabricatorConduitSearchEngine.php
+++ b/src/applications/conduit/query/PhabricatorConduitSearchEngine.php
@@ -37,6 +37,7 @@
     $query->withIsStable($saved->getParameter('isStable'));
     $query->withIsUnstable($saved->getParameter('isUnstable'));
     $query->withIsDeprecated($saved->getParameter('isDeprecated'));
+    $query->withIsInternal(false);
 
     $names = $saved->getParameter('applicationNames', array());
     if ($names) {
diff --git a/src/applications/diffusion/conduit/DiffusionInternalGitRawDiffQueryConduitAPIMethod.php b/src/applications/diffusion/conduit/DiffusionInternalGitRawDiffQueryConduitAPIMethod.php
new file mode 100644
--- /dev/null
+++ b/src/applications/diffusion/conduit/DiffusionInternalGitRawDiffQueryConduitAPIMethod.php
@@ -0,0 +1,74 @@
+<?php
+
+final class DiffusionInternalGitRawDiffQueryConduitAPIMethod
+  extends DiffusionQueryConduitAPIMethod {
+
+  public function isInternalAPI() {
+    return true;
+  }
+
+  public function getAPIMethodName() {
+    return 'diffusion.internal.gitrawdiffquery';
+  }
+
+  public function getMethodDescription() {
+    return pht('Internal method for getting raw diff information.');
+  }
+
+  protected function defineReturnType() {
+    return 'string';
+  }
+
+  protected function defineCustomParamTypes() {
+    return array(
+      'commit' => 'required string',
+    );
+  }
+
+  protected function getResult(ConduitAPIRequest $request) {
+    $drequest = $this->getDiffusionRequest();
+    $repository = $drequest->getRepository();
+
+    if (!$repository->isGit()) {
+      throw new Exception(
+        pht(
+          'This API method can only be called on Git repositories.'));
+    }
+
+    // Check if the commit has parents. We're testing to see whether it is the
+    // first commit in history (in which case we must use "git log") or some
+    // other commit (in which case we can use "git diff"). We'd rather use
+    // "git diff" because it has the right behavior for merge commits, but
+    // it requires the commit to have a parent that we can diff against. The
+    // first commit doesn't, so "commit^" is not a valid ref.
+    list($parents) = $repository->execxLocalCommand(
+      'log -n1 --format=%s %s',
+      '%P',
+      $request->getValue('commit'));
+
+    $use_log = !strlen(trim($parents));
+    if ($use_log) {
+      // This is the first commit so we need to use "log". We know it's not a
+      // merge commit because it couldn't be merging anything, so this is safe.
+
+      // NOTE: "--pretty=format: " is to disable diff output, we only want the
+      // part we get from "--raw".
+      list($raw) = $repository->execxLocalCommand(
+        'log -n1 -M -C -B --find-copies-harder --raw -t '.
+          '--pretty=format: --abbrev=40 %s',
+        $request->getValue('commit'));
+    } else {
+      // Otherwise, we can use "diff", which will give us output for merges.
+      // We diff against the first parent, as this is generally the expectation
+      // and results in sensible behavior.
+      list($raw) = $repository->execxLocalCommand(
+        'diff -n1 -M -C -B --find-copies-harder --raw -t '.
+          '--abbrev=40 %s^1 %s',
+        $request->getValue('commit'),
+        $request->getValue('commit'));
+    }
+
+    return $raw;
+  }
+
+}
diff --git a/src/applications/repository/worker/commitchangeparser/PhabricatorRepositoryGitCommitChangeParserWorker.php b/src/applications/repository/worker/commitchangeparser/PhabricatorRepositoryGitCommitChangeParserWorker.php
--- a/src/applications/repository/worker/commitchangeparser/PhabricatorRepositoryGitCommitChangeParserWorker.php
+++ b/src/applications/repository/worker/commitchangeparser/PhabricatorRepositoryGitCommitChangeParserWorker.php
@@ -7,38 +7,18 @@
     PhabricatorRepository $repository,
     PhabricatorRepositoryCommit $commit) {
 
-    // Check if the commit has parents. We're testing to see whether it is the
-    // first commit in history (in which case we must use "git log") or some
-    // other commit (in which case we can use "git diff"). We'd rather use
-    // "git diff" because it has the right behavior for merge commits, but
-    // it requires the commit to have a parent that we can diff against. The
-    // first commit doesn't, so "commit^" is not a valid ref.
-    list($parents) = $repository->execxLocalCommand(
-      'log -n1 --format=%s %s',
-      '%P',
-      $commit->getCommitIdentifier());
-
-    $use_log = !strlen(trim($parents));
-    if ($use_log) {
-      // This is the first commit so we need to use "log". We know it's not a
-      // merge commit because it couldn't be merging anything, so this is safe.
-
-      // NOTE: "--pretty=format: " is to disable diff output, we only want the
-      // part we get from "--raw".
-      list($raw) = $repository->execxLocalCommand(
-        'log -n1 -M -C -B --find-copies-harder --raw -t '.
-          '--pretty=format: --abbrev=40 %s',
-        $commit->getCommitIdentifier());
-    } else {
-      // Otherwise, we can use "diff", which will give us output for merges.
-      // We diff against the first parent, as this is generally the expectation
-      // and results in sensible behavior.
-      list($raw) = $repository->execxLocalCommand(
-        'diff -n1 -M -C -B --find-copies-harder --raw -t '.
-          '--abbrev=40 %s^1 %s',
-        $commit->getCommitIdentifier(),
-        $commit->getCommitIdentifier());
-    }
+    $viewer = PhabricatorUser::getOmnipotentUser();
+    $raw = DiffusionQuery::callConduitWithDiffusionRequest(
+      $viewer,
+      DiffusionRequest::newFromDictionary(
+        array(
+          'repository' => $repository,
+          'user' => $viewer,
+        )),
+      'diffusion.internal.gitrawdiffquery',
+      array(
+        'commit' => $commit->getCommitIdentifier(),
+      ));
 
     $changes = array();
     $move_away = array();