Add "Dominion" rules for Owners Packages

Summary:
Ref T10939. This supports two settings for packages (although they can't be configured yet):

  - **Strong Dominion**: If the package owns `a/`, it always owns every subpath, even if another package also owns the subpath. For example, if I own `src/differential/`, I always own it even if someone else claims `src/differential/js/` as part of the "Javascript" package. This is the current behavior, and the default.
  - **Weak Dominion**: If the package owns `a/`, but another package owns `a/b/`, the package gives up control of those paths and no longer owns paths in `a/b/`. This is a new behavior which can make defining some types of packages easier.

In the next change, I'll allow users to switch these modes and document what they mean.

Test Plan:
  - Ran existing unit tests.
  - Added new unit tests.

Reviewers: chad

Reviewed By: chad

Subscribers: joel

Maniphest Tasks: T10939

Differential Revision: https://secure.phabricator.com/D15935

src/applications/owners/storage/PhabricatorOwnersPackage.php

@@ -34,6 +34,9 @@ final class PhabricatorOwnersPackage
   const AUTOREVIEW_REVIEW = 'review';
   const AUTOREVIEW_BLOCK = 'block';
 
+  const DOMINION_STRONG = 'strong';
+  const DOMINION_WEAK = 'weak';
+
   public static function initializeNewPackage(PhabricatorUser $actor) {
     $app = id(new PhabricatorApplicationQuery())
       ->setViewer($actor)
@@ -190,7 +193,7 @@ final class PhabricatorOwnersPackage
     foreach (array_chunk(array_keys($fragments), 128) as $chunk) {
       $rows[] = queryfx_all(
         $conn,
-        'SELECT pkg.id, p.excluded, p.path
+        'SELECT pkg.id, "strong" dominion, p.excluded, p.path
           FROM %T pkg JOIN %T p ON p.packageID = pkg.id
           WHERE p.path IN (%Ls) %Q',
         $package->getTableName(),
@@ -232,35 +235,100 @@ final class PhabricatorOwnersPackage
   }
 
   public static function findLongestPathsPerPackage(array $rows, array $paths) {
-    $ids = array();
 
-    foreach (igroup($rows, 'id') as $id => $package_paths) {
+    // Build a map from each path to all the package paths which match it.
-      $relevant_paths = array_select_keys(
+    $path_hits = array();
-        $paths,
+    $weak = array();
-        ipull($package_paths, 'path'));
+    foreach ($rows as $row) {
+      $id = $row['id'];
+      $path = $row['path'];
+      $length = strlen($path);
+      $excluded = $row['excluded'];
 
-      // For every package, remove all excluded paths.
+      if ($row['dominion'] === self::DOMINION_WEAK) {
-      $remove = array();
+        $weak[$id] = true;
-      foreach ($package_paths as $package_path) {
+      }
-        if ($package_path['excluded']) {
+
-          $remove += idx($relevant_paths, $package_path['path'], array());
+      $matches = $paths[$path];
-          unset($relevant_paths[$package_path['path']]);
+      foreach ($matches as $match => $ignored) {
+        $path_hits[$match][] = array(
+          'id' => $id,
+          'excluded' => $excluded,
+          'length' => $length,
+        );
       }
     }
 
-      if ($remove) {
+    // For each path, process the matching package paths to figure out which
-        foreach ($relevant_paths as $fragment => $fragment_paths) {
+    // packages actually own it.
-          $relevant_paths[$fragment] = array_diff_key($fragment_paths, $remove);
+    $path_packages = array();
+    foreach ($path_hits as $match => $hits) {
+      $hits = isort($hits, 'length');
+
+      $packages = array();
+      foreach ($hits as $hit) {
+        $package_id = $hit['id'];
+        if ($hit['excluded']) {
+          unset($packages[$package_id]);
+        } else {
+          $packages[$package_id] = $hit;
         }
       }
 
-      $relevant_paths = array_filter($relevant_paths);
+      $path_packages[$match] = $packages;
-      if ($relevant_paths) {
+    }
-        $ids[$id] = max(array_map('strlen', array_keys($relevant_paths)));
+
+    // Remove packages with weak dominion rules that should cede control to
+    // a more specific package.
+    if ($weak) {
+      foreach ($path_packages as $match => $packages) {
+        $packages = isort($packages, 'length');
+        $packages = array_reverse($packages, true);
+
+        $first = null;
+        foreach ($packages as $package_id => $package) {
+          // If this is the first package we've encountered, note it and
+          // continue. We're iterating over the packages from longest to
+          // shortest match, so this package always has the strongest claim
+          // on the path.
+          if ($first === null) {
+            $first = $package_id;
+            continue;
+          }
+
+          // If this is the first package we saw, its claim stands even if it
+          // is a weak package.
+          if ($first === $package_id) {
+            continue;
+          }
+
+          // If this is a weak package and not the first package we saw,
+          // cede its claim to the stronger package.
+          if (isset($weak[$package_id])) {
+            unset($packages[$package_id]);
           }
         }
 
-    return $ids;
+        $path_packages[$match] = $packages;
+      }
+    }
+
+    // For each package that owns at least one path, identify the longest
+    // path it owns.
+    $package_lengths = array();
+    foreach ($path_packages as $match => $hits) {
+      foreach ($hits as $hit) {
+        $length = $hit['length'];
+        $id = $hit['id'];
+        if (empty($package_lengths[$id])) {
+          $package_lengths[$id] = $length;
+        } else {
+          $package_lengths[$id] = max($package_lengths[$id], $length);
+        }
+      }
+    }
+
+    return $package_lengths;
   }
 
   public static function splitPath($path) {

src/applications/owners/storage/__tests__/PhabricatorOwnersPackageTestCase.php

@@ -4,9 +4,24 @@ final class PhabricatorOwnersPackageTestCase extends PhabricatorTestCase {
 
   public function testFindLongestPathsPerPackage() {
     $rows = array(
-      array('id' => 1, 'excluded' => 0, 'path' => 'src/'),
+      array(
-      array('id' => 1, 'excluded' => 1, 'path' => 'src/releeph/'),
+        'id' => 1,
-      array('id' => 2, 'excluded' => 0, 'path' => 'src/releeph/'),
+        'excluded' => 0,
+        'dominion' => PhabricatorOwnersPackage::DOMINION_STRONG,
+        'path' => 'src/',
+      ),
+      array(
+        'id' => 1,
+        'excluded' => 1,
+        'dominion' => PhabricatorOwnersPackage::DOMINION_STRONG,
+        'path' => 'src/releeph/',
+      ),
+      array(
+        'id' => 2,
+        'excluded' => 0,
+        'dominion' => PhabricatorOwnersPackage::DOMINION_STRONG,
+        'path' => 'src/releeph/',
+      ),
     );
 
     $paths = array(
@@ -29,6 +44,62 @@ final class PhabricatorOwnersPackageTestCase extends PhabricatorTestCase {
         2 => strlen('src/releeph/'),
       ),
       PhabricatorOwnersPackage::findLongestPathsPerPackage($rows, $paths));
+
+
+    // Test packages with weak dominion. Here, only package #2 should own the
+    // path. Package #1's claim is ceded to Package #2 because it uses weak
+    // rules. Package #2 gets the claim even though it also has weak rules
+    // because there is no more-specific package.
+
+    $rows = array(
+      array(
+        'id' => 1,
+        'excluded' => 0,
+        'dominion' => PhabricatorOwnersPackage::DOMINION_WEAK,
+        'path' => 'src/',
+      ),
+      array(
+        'id' => 2,
+        'excluded' => 0,
+        'dominion' => PhabricatorOwnersPackage::DOMINION_WEAK,
+        'path' => 'src/applications/',
+      ),
+    );
+
+    $pvalue = array('src/applications/main/main.c' => true);
+
+    $paths = array(
+      'src/' => $pvalue,
+      'src/applications/' => $pvalue,
+    );
+
+    $this->assertEqual(
+      array(
+        2 => strlen('src/applications/'),
+      ),
+      PhabricatorOwnersPackage::findLongestPathsPerPackage($rows, $paths));
+
+
+    // Now, add a more specific path to Package #1. This tests nested ownership
+    // in packages with weak dominion rules. This time, Package #1 should end
+    // up back on top, with Package #2 cedeing control to its more specific
+    // path.
+    $rows[] = array(
+      'id' => 1,
+      'excluded' => 0,
+      'dominion' => PhabricatorOwnersPackage::DOMINION_WEAK,
+      'path' => 'src/applications/main/',
+    );
+
+    $paths['src/applications/main/'] = $pvalue;
+
+    $this->assertEqual(
+      array(
+        1 => strlen('src/applications/main/'),
+      ),
+      PhabricatorOwnersPackage::findLongestPathsPerPackage($rows, $paths));
+
+
   }
 
 }