From fd6ee50e06cb48c9e3a476bf23285875484ff5f7 Mon Sep 17 00:00:00 2001
From: Oleg Pudeyev <oleg@bsdpower.com>
Date: Fri, 2 Nov 2012 16:05:53 -0400
Subject: [PATCH] [ticket/11162] Extract existing behavior into a function and
 add a test.

PHPBB3-11162
---
 phpBB/includes/functions.php                  | 24 ++++++-
 tests/functions/fixtures/duplicates.xml       | 56 +++++++++++++++
 .../update_rows_avoiding_duplicates_test.php  | 71 +++++++++++++++++++
 3 files changed, 150 insertions(+), 1 deletion(-)
 create mode 100644 tests/functions/fixtures/duplicates.xml
 create mode 100644 tests/functions/update_rows_avoiding_duplicates_test.php

diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 65d8be32ad..8608c6ca4f 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -1297,6 +1297,28 @@ function tz_select($default = '', $truncate = false)
 	return $tz_select;
 }
 
+/**
+* Updates rows in given table from a set of values to a new value.
+* If this results in rows violating uniqueness constraints, the duplicate
+* rows are eliminated.
+*
+* @param dbal $db Database object
+* @param string $table Table on which to perform the update
+* @param string $column Column whose values to change
+* @param array $from_values An array of values that should be changed
+* @param int $to_value The new value
+* @return null
+*/
+function phpbb_update_rows_avoiding_duplicates($db, $table, $column, $from_values, $to_value)
+{
+	$db->sql_return_on_error(true);
+	$condition = $db->sql_in_set($column, $from_values);
+	$db->sql_query('UPDATE ' . $table . ' SET ' . $column . ' = ' . (int) $to_value. ' WHERE ' . $condition);
+	$db->sql_return_on_error(false);
+
+	$db->sql_query('DELETE FROM ' . $table . ' WHERE ' . $condition);
+}
+
 // Functions handling topic/post tracking/marking
 
 /**
@@ -3355,7 +3377,7 @@ function parse_cfg_file($filename, $lines = false)
 
 		$parsed_items[$key] = $value;
 	}
-	
+
 	if (isset($parsed_items['inherit_from']) && isset($parsed_items['name']) && $parsed_items['inherit_from'] == $parsed_items['name'])
 	{
 		unset($parsed_items['inherit_from']);
diff --git a/tests/functions/fixtures/duplicates.xml b/tests/functions/fixtures/duplicates.xml
new file mode 100644
index 0000000000..bc08016a8f
--- /dev/null
+++ b/tests/functions/fixtures/duplicates.xml
@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<dataset>
+	<table name="phpbb_topics_watch">
+		<column>user_id</column>
+		<column>topic_id</column>
+		<column>notify_status</column>
+
+		<!-- one entry for this topic -->
+		<row>
+			<value>1</value>
+			<value>1</value>
+			<value>1</value>
+		</row>
+
+		<!-- non-conflicting entries -->
+		<row>
+			<value>2</value>
+			<value>2</value>
+			<value>1</value>
+		</row>
+		<row>
+			<value>3</value>
+			<value>3</value>
+			<value>1</value>
+		</row>
+
+		<!-- conflicting entries -->
+		<row>
+			<value>1</value>
+			<value>4</value>
+			<value>1</value>
+		</row>
+		<row>
+			<value>1</value>
+			<value>5</value>
+			<value>1</value>
+		</row>
+
+		<!-- conflicting and non-conflicting entries -->
+		<row>
+			<value>1</value>
+			<value>6</value>
+			<value>1</value>
+		</row>
+		<row>
+			<value>1</value>
+			<value>7</value>
+			<value>1</value>
+		</row>
+		<row>
+			<value>2</value>
+			<value>6</value>
+			<value>1</value>
+		</row>
+	</table>
+</dataset>
diff --git a/tests/functions/update_rows_avoiding_duplicates_test.php b/tests/functions/update_rows_avoiding_duplicates_test.php
new file mode 100644
index 0000000000..0e949717d2
--- /dev/null
+++ b/tests/functions/update_rows_avoiding_duplicates_test.php
@@ -0,0 +1,71 @@
+<?php
+/**
+*
+* @package testing
+* @copyright (c) 2012 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*
+*/
+
+require_once dirname(__FILE__) . '/../../phpBB/includes/functions.php';
+
+class phpbb_update_rows_avoiding_duplicates_test extends phpbb_database_test_case
+{
+	public function getDataSet()
+	{
+		return $this->createXMLDataSet(dirname(__FILE__).'/fixtures/duplicates.xml');
+	}
+
+	public static function fixture_data()
+	{
+		return array(
+			// description
+			// from array
+			// to value
+			// expected count with to value post update
+			array(
+				'trivial',
+				array(1),
+				10,
+				1,
+			),
+			array(
+				'no conflict',
+				array(2),
+				3,
+				2,
+			),
+			array(
+				'conflict',
+				array(4),
+				5,
+				1,
+			),
+			array(
+				'conflict and no conflict',
+				array(6),
+				7,
+				2,
+			),
+		);
+	}
+
+	/**
+	* @dataProvider fixture_data
+	*/
+	public function test_trivial_update($description, $from, $to, $expected_result_count)
+	{
+		$db = $this->new_dbal();
+
+		phpbb_update_rows_avoiding_duplicates($db, TOPICS_WATCH_TABLE, 'topic_id', $from, $to);
+
+		$sql = 'SELECT count(*) AS count
+			FROM ' . TOPICS_WATCH_TABLE . '
+			WHERE topic_id = ' . $db->sql_escape($to);
+		$result = $db->sql_query($sql);
+		$result_count = $db->sql_fetchfield('count');
+		$db->sql_freeresult($result);
+
+		$this->assertEquals($expected_result_count, $result_count);
+	}
+}