Check replicas are there, when meta_p.wiki says so

src/Model/Project.php

@@ -116,7 +116,8 @@ protected function getMetadata(): ?array
      */
     public function exists(): bool
     {
-        return !empty($this->getDomain());
+        return (!empty($this->getDomain()))
+            && $this->repository->checkReplication($this->getBasicInfo()['dbName']);
     }
 
     /**

src/Repository/GlobalContribsRepository.php

@@ -60,6 +60,7 @@ public function globalEditCounts(User $user): ?array
 
         // Pre-populate all projects' metadata, to prevent each project call from fetching it.
         $this->caProject->getRepository()->getAll();
+        $this->checkReplicationAllProjects();
 
         // Compile the output.
         $out = [];
@@ -117,6 +118,34 @@ protected function globalEditCountsFromCentralAuth(User $user): ?array
         return $this->setCache($cacheKey, $out);
     }
 
+    /**
+     * Get, slice by slice, the list of projects that are actually replicated.
+     * Takes about 0.5s per slice.
+     * @return bool[] Keyed by database name, all values are true.
+     */
+    public function checkReplicationAllProjects(): array
+    {
+        $cacheKey = $this->getCacheKey("global_replication_check");
+        if ($this->cache->hasItem($cacheKey)) {
+            return $this->cache->getItem($cacheKey)->get();
+        }
+        $result = [];
+        $exists = true;
+        $i = 0;
+        $sql = "SELECT DISTINCT table_schema
+                FROM information_schema.tables";
+        while ($exists) {
+            $i += 1;
+            try {
+                $queryResult = $this->executeProjectsQuery("s$i", $sql)->fetchFirstColumn();
+                $result = array_merge($result, $queryResult);
+            } catch (\Throwable) {
+                $exists = false;
+            }
+        }
+        return $this->setCache($cacheKey, $result, 'PT1H');
+    }
+
     /**
      * Loop through the given dbNames and create Project objects for each.
      * @param array $dbNames

src/Repository/ProjectRepository.php

@@ -241,6 +241,47 @@ public function getOne(string $project): ?array
         return $this->setCache($cacheKey, $basicInfo, 'PT1H');
     }
 
+    /**
+     * Is this project actually replicated? Sometimes projets aren't,
+     * despite being listed in meta_p.wiki. See T322466.
+     * @param string $project Database name, without _p.
+     * @return bool
+     */
+    public function checkReplication(string $project): bool
+    {
+        if ('' == $project) {
+            // This means we failed to getBasicInfo. Let's try and AGF.
+            // Plus, keeps tests from breaking down.
+            return true;
+        }
+        $cacheKey = $this->getCacheKey($project, "replication_check");
+        if ($this->cache->hasItem($cacheKey)) {
+            return $this->cache->getItem($cacheKey)->get();
+        }
+        // GlobalContribs preloads replication checks for *all* projects
+        $allProjectsCacheKey = $this->getCacheKey('', "global_replication_check");
+        if ($this->cache->hasItem($allProjectsCacheKey)) {
+            $globalReplicationChecks = $this->cache->getItem($allProjectsCacheKey)->get();
+            return array_key_exists($project, $globalReplicationChecks);
+        }
+        $dbList = $this->getDbList();
+        if (!array_key_exists($project, $dbList)) {
+            $result = false;
+        } else {
+            $dbSlice = $dbList[$project];
+            $sql = "SELECT 1
+                    FROM information_schema.tables
+                    WHERE table_schema = :project
+                    LIMIT 1";
+            $queryResult = $this->executeProjectsQuery($dbSlice, $sql, [
+                'project' => $project . "_p",
+            ])->fetchAssociative();
+            $result = (1 == count($queryResult));
+        }
+        // Cache for 1h and return
+        return $this->setCache($cacheKey, $result, 'PT1H'); // feels long to me, but as long as getOne
+    }
+
     /**
      * Get metadata about a project, including the 'dbName', 'url' and 'lang'
      *

tests/Model/GlobalContribsTest.php

@@ -90,6 +90,8 @@ public function testGlobalEdits(): void
                 'dbName' => 'wiki1',
                 'url' => 'https://wiki1.example.org',
             ]);
+        $wiki1Repo->method('checkReplication')
+            ->willReturn(true);
         $wiki1 = new Project('wiki1');
         $wiki1->setRepository($wiki1Repo);
 

tests/TestAdapter.php

@@ -32,6 +32,8 @@ public function getProjectRepo(): MockObject
                 'dbName' => 'test_wiki',
                 'lang' => 'en',
             ]);
+        $repo->method('checkReplication')
+            ->willReturn(true);
         return $repo;
     }