Show a better message for empty repositories and invalid branches

Summary:
Ref T1493.

  - When viewing an invalid branch, show a "there is no such branch" message.
  - When viewing an empty repository, show a "this repository is empty" message.

Test Plan:
  - Viewed empty, bad branch, and nonempty in Git.
  - Viewed empty, bad branch, and nonempty in Mercurial.
  - Viewed empty and nonempty in Subversion.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: epriestley

Maniphest Tasks: T1493

Differential Revision: https://secure.phabricator.com/D9912

src/applications/diffusion/controller/DiffusionRepositoryController.php

@@ -7,6 +7,9 @@ final class DiffusionRepositoryController extends DiffusionController {
   }
 
   public function processRequest() {
+    $request = $this->getRequest();
+    $viewer = $request->getUser();
+
     $drequest = $this->getDiffusionRequest();
     $repository = $drequest->getRepository();
 
@@ -16,7 +19,74 @@ final class DiffusionRepositoryController extends DiffusionController {
     $content[] = $crumbs;
 
     $content[] = $this->buildPropertiesTable($drequest->getRepository());
+
+    // Before we do any work, make sure we're looking at a some content: we're
+    // on a valid branch, and the repository is not empty.
+    $page_has_content = false;
+    $empty_title = null;
+    $empty_message = null;
+
+    // If this VCS supports branches, check that the selected branch actually
+    // exists.
+    if ($drequest->supportsBranches()) {
+      $ref_cursor = id(new PhabricatorRepositoryRefCursorQuery())
+        ->setViewer($viewer)
+        ->withRepositoryPHIDs(array($repository->getPHID()))
+        ->withRefTypes(array(PhabricatorRepositoryRefCursor::TYPE_BRANCH))
+        ->withRefNames(array($drequest->getBranch()))
+        ->executeOne();
+      if ($ref_cursor) {
+        // This is a valid branch, so we necessarily have some content.
+        $page_has_content = true;
+      } else {
+        $empty_title = pht('No Such Branch');
+        $empty_message = pht(
+          'There is no branch named "%s" in this repository.',
+          $drequest->getBranch());
+      }
+    }
+
+    // If we didn't find any branches, check if there are any commits at all.
+    // This can tailor the message for empty repositories.
+    if (!$page_has_content) {
+      $any_commit = id(new DiffusionCommitQuery())
+        ->setViewer($viewer)
+        ->withRepository($repository)
+        ->setLimit(1)
+        ->execute();
+      if ($any_commit) {
+        if (!$drequest->supportsBranches()) {
+          $page_has_content = true;
+        }
+      } else {
+        $empty_title = pht('Empty Repository');
+        $empty_message = pht(
+          'This repository does not have any commits yet.');
+      }
+    }
+
+    if ($page_has_content) {
+      $content[] = $this->buildNormalContent($drequest);
+    } else {
+      $content[] = id(new AphrontErrorView())
+        ->setTitle($empty_title)
+        ->setSeverity(AphrontErrorView::SEVERITY_WARNING)
+        ->setErrors(array($empty_message));
+    }
+
+    return $this->buildApplicationPage(
+      $content,
+      array(
+        'title' => $drequest->getRepository()->getName(),
+      ));
+  }
+
+
+  private function buildNormalContent(DiffusionRequest $drequest) {
+    $repository = $drequest->getRepository();
+
     $phids = array();
+    $content = array();
 
     try {
       $history_results = $this->callConduitWithDiffusionRequest(
@@ -133,11 +203,7 @@ final class DiffusionRepositoryController extends DiffusionController {
       $content[] = $panel;
     }
 
-    return $this->buildApplicationPage(
-      $content,
-      array(
-        'title' => $drequest->getRepository()->getName(),
-      ));
+    return $content;
   }
 
   private function buildPropertiesTable(PhabricatorRepository $repository) {

src/applications/diffusion/request/DiffusionGitRequest.php

@@ -2,7 +2,7 @@
 
 final class DiffusionGitRequest extends DiffusionRequest {
 
-  protected function getSupportsBranches() {
+  public function supportsBranches() {
     return true;
   }
 

src/applications/diffusion/request/DiffusionMercurialRequest.php

@@ -2,7 +2,7 @@
 
 final class DiffusionMercurialRequest extends DiffusionRequest {
 
-  protected function getSupportsBranches() {
+  public function supportsBranches() {
     return true;
   }
 

src/applications/diffusion/request/DiffusionRequest.php

@@ -28,7 +28,7 @@ abstract class DiffusionRequest {
   private $user;
   private $branchObject = false;
 
-  abstract protected function getSupportsBranches();
+  abstract public function supportsBranches();
   abstract protected function isStableCommit($symbol);
 
   protected function didInitialize() {
@@ -98,7 +98,7 @@ abstract class DiffusionRequest {
     $callsign = phutil_unescape_uri_path_component(idx($data, 'callsign'));
     $object = self::newFromCallsign($callsign, $request->getUser());
 
-    $use_branches = $object->getSupportsBranches();
+    $use_branches = $object->supportsBranches();
     $parsed = self::parseRequestBlob(idx($data, 'dblob'), $use_branches);
 
     $object->setUser($request->getUser());
@@ -188,7 +188,7 @@ abstract class DiffusionRequest {
     $this->initFromConduit = idx($data, 'initFromConduit', true);
 
     $this->symbolicCommit = idx($data, 'commit');
-    if ($this->getSupportsBranches()) {
+    if ($this->supportsBranches()) {
       $this->branch = idx($data, 'branch');
     }
 
@@ -712,7 +712,7 @@ abstract class DiffusionRequest {
     if ($this->symbolicCommit) {
       $ref = $this->symbolicCommit;
     } else {
-      if ($this->getSupportsBranches()) {
+      if ($this->supportsBranches()) {
         $ref = $this->getResolvableBranchName($this->getBranch());
       } else {
         $ref = 'HEAD';

src/applications/diffusion/request/DiffusionSvnRequest.php

@@ -2,7 +2,7 @@
 
 final class DiffusionSvnRequest extends DiffusionRequest {
 
-  protected function getSupportsBranches() {
+  public function supportsBranches() {
     return false;
   }
 

src/applications/repository/query/PhabricatorRepositoryRefCursorQuery.php

@@ -5,6 +5,7 @@ final class PhabricatorRepositoryRefCursorQuery
 
   private $repositoryPHIDs;
   private $refTypes;
+  private $refNames;
 
   public function withRepositoryPHIDs(array $phids) {
     $this->repositoryPHIDs = $phids;
@@ -16,6 +17,11 @@ final class PhabricatorRepositoryRefCursorQuery
     return $this;
   }
 
+  public function withRefNames(array $names) {
+    $this->refNames = $names;
+    return $this;
+  }
+
   protected function loadPage() {
     $table = new PhabricatorRepositoryRefCursor();
     $conn_r = $table->establishConnection('r');
@@ -56,20 +62,32 @@ final class PhabricatorRepositoryRefCursorQuery
   private function buildWhereClause(AphrontDatabaseConnection $conn_r) {
     $where = array();
 
-    if ($this->repositoryPHIDs) {
+    if ($this->repositoryPHIDs !== null) {
       $where[] = qsprintf(
         $conn_r,
         'repositoryPHID IN (%Ls)',
         $this->repositoryPHIDs);
     }
 
-    if ($this->refTypes) {
+    if ($this->refTypes !== null) {
       $where[] = qsprintf(
         $conn_r,
         'refType IN (%Ls)',
         $this->refTypes);
     }
 
+    if ($this->refNames !== null) {
+      $name_hashes = array();
+      foreach ($this->refNames as $name) {
+        $name_hashes[] = PhabricatorHash::digestForIndex($name);
+      }
+
+      $where[] = qsprintf(
+        $conn_r,
+        'refNameHash IN (%Ls)',
+        $name_hashes);
+    }
+
     $where[] = $this->buildPagingClause($conn_r);
 
     return $this->formatWhereClause($where);