MDL-50770 blocks: remove orphaned block positions

lib/db/upgrade.php

@@ -2525,5 +2525,16 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2017020200.02);
     }
 
+    if ($oldversion < 2017020901.00) {
+
+        // Delete "orphaned" block positions. Note, the query does not use indexes (because there are none),
+        // if it runs too long during upgrade you can comment this line - it will leave orphaned records
+        // in the database but they won't bother you.
+        upgrade_block_positions();
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2017020901.00);
+    }
+
     return true;
 }

lib/db/upgradelib.php

@@ -527,3 +527,18 @@ function upgrade_standardise_score($rawgrade, $sourcemin, $sourcemax, $targetmin
     $standardisedvalue = $factor * $diff + $targetmin;
     return $standardisedvalue;
 }
+
+/**
+ * Delete orphaned records in block_positions
+ */
+function upgrade_block_positions() {
+    global $DB;
+    $id = 'id';
+    if ($DB->get_dbfamily() !== 'mysql') {
+        // Field block_positions.subpage has type 'char', it can not be compared to int in db engines except for mysql.
+        $id = $DB->sql_concat('?', 'id');
+    }
+    $sql = "DELETE FROM {block_positions}
+    WHERE pagetype IN ('my-index', 'user-profile') AND subpage NOT IN (SELECT $id FROM {my_pages})";
+    $DB->execute($sql, ['']);
+}

lib/tests/upgradelib_test.php

@@ -882,4 +882,47 @@ public function test_check_libcurl_version() {
             $this->assertNull(check_libcurl_version($result));
         }
     }
+
+    /**
+     * Create two pages with blocks, delete one page and make sure upgrade script deletes orphaned blocks
+     */
+    public function test_delete_block_positions() {
+        global $DB, $CFG;
+        require_once($CFG->dirroot . '/my/lib.php');
+        $this->resetAfterTest();
+
+        // Make sure each block on system dashboard page has a position.
+        $systempage = $DB->get_record('my_pages', array('userid' => null, 'private' => MY_PAGE_PRIVATE));
+        $systemcontext = context_system::instance();
+        $blockinstances = $DB->get_records('block_instances', array('parentcontextid' => $systemcontext->id,
+            'pagetypepattern' => 'my-index', 'subpagepattern' => $systempage->id));
+        $this->assertNotEmpty($blockinstances);
+        foreach ($blockinstances as $bi) {
+            $DB->insert_record('block_positions', ['subpage' => $systempage->id, 'pagetype' => 'my-index', 'contextid' => $systemcontext->id,
+                'blockinstanceid' => $bi->id, 'visible' => 1, 'weight' => $bi->defaultweight]);
+        }
+
+        // Create two users and make two copies of the system dashboard.
+        $user1 = $this->getDataGenerator()->create_user();
+        $user2 = $this->getDataGenerator()->create_user();
+        $page1 = my_copy_page($user1->id, MY_PAGE_PRIVATE, 'my-index');
+        $page2 = my_copy_page($user2->id, MY_PAGE_PRIVATE, 'my-index');
+
+        $context1 = context_user::instance($user1->id);
+        $context2 = context_user::instance($user2->id);
+
+        // Delete second page without deleting block positions.
+        $DB->delete_records('my_pages', ['id' => $page2->id]);
+
+        // Blocks are still here.
+        $this->assertEquals(count($blockinstances), $DB->count_records('block_positions', ['subpage' => $page1->id, 'pagetype' => 'my-index', 'contextid' => $context1->id]));
+        $this->assertEquals(count($blockinstances), $DB->count_records('block_positions', ['subpage' => $page2->id, 'pagetype' => 'my-index', 'contextid' => $context2->id]));
+
+        // Run upgrade script that should delete orphaned block_positions.
+        upgrade_block_positions();
+
+        // First user still has all his block_positions, second user does not.
+        $this->assertEquals(count($blockinstances), $DB->count_records('block_positions', ['subpage' => $page1->id, 'pagetype' => 'my-index', 'contextid' => $context1->id]));
+        $this->assertEquals(0, $DB->count_records('block_positions', ['subpage' => $page2->id, 'pagetype' => 'my-index']));
+    }
 }

version.php

@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2017020900.00;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2017020901.00;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.