While testing the API with idSite=all on my development instance I noticed that calling any API function with idSite=all results in an error when there is only one site.

Specifically, I get the following Error:

```
Recoverable Error: Argument 1 passed to Piwik_Date::isEarlier() must be an instance of Piwik_Date, null given, called in /Users/patrick/projects/sandwichboard/stats/modules/Archive/Single.php on line 143 and defined in /Users/patrick/projects/sandwichboard/stats/modules/Date.php on line 107

Backtrace —>

1. Piwik_ErrorHandler(4096, Argument 1 passed to Piwik_Date::isEarlier() must be an instance of Piwik_Date, null given, called in /Users/patrick/projects/sandwichboard/stats/modules/Archive/Single.php on line 143 and defined, /Users/patrick/projects/sandwichboard/stats/modules/Date.php, 107, Array ()) called at [/Users/patrick/projects/sandwichboard/stats/modules/Date.php:107]
2. Piwik_Date→isEarlier() called at [/Users/patrick/projects/sandwichboard/stats/modules/Archive/Single.php:143]
3. Piwik_Archive_Single→prepareArchive() called at [/Users/patrick/projects/sandwichboard/stats/modules/Archive/Array/IndexedByDate.php:20]
4. Piwik_Archive_Array_IndexedByDate→__construct(Piwik_Site Object ([] => all), day, last30) called at [/Users/patrick/projects/sandwichboard/stats/modules/Archive.php:106]
5. Piwik_Archive::build(all, day, last30) called at [/Users/patrick/projects/sandwichboard/stats/plugins/VisitsSummary/API.php:49]
6. Piwik_VisitsSummary_API→getNumeric(all, day, last30, nb_visits) called at [/Users/patrick/projects/sandwichboard/stats/plugins/VisitsSummary/API.php:56]
7. Piwik_VisitsSummary_API→getVisits(all, day, last30)
8. call_user_func_array(Array (<sup>0</sup> => Piwik_VisitsSummary_API Object (),<sup>1</sup> => getVisits), Array (<sup>0</sup> => all,<sup>1</sup> => day,<sup>2</sup> => last30)) called at [/Users/patrick/projects/sandwichboard/stats/modules/API/Proxy.php:462]
9. Piwik_API_Proxy→__call(getVisits, Array (<sup>0</sup> => all,<sup>1</sup> => day,<sup>2</sup> => last30))
10. Piwik_API_Proxy→getVisits(all, day, last30)
11. call_user_func_array(Array (<sup>0</sup> => Piwik_API_Proxy Object ([] => Array ([VisitsSummary] => 1),[] => Array ([Piwik_VisitsSummary_API] => Array ([get] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3),[getVisits] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3),[getUniqueVisitors] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3),[getActions] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3),[getMaxActions] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3),[getSumVisitsLength] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3),[getBounceCount] => Array ([parameters] => Array ([idSite] => ,[period] => ,[date] => ),[numberOfRequiredParameters] => 3)))),<sup>1</sup> => getVisits), Array (<sup>0</sup> => all,<sup>1</sup> => day,<sup>2</sup> => last30)) called at [/Users/patrick/projects/sandwichboard/stats/modules/API/Request.php:141]
12. Piwik_API_Request→process() called at [/Users/patrick/projects/sandwichboard/stats/plugins/API/Controller.php:24]
13. Piwik_API_Controller→index()
14. call_user_func_array(Array (<sup>0</sup> => Piwik_API_Controller Object ([] => API,[] => last30,[] => ),<sup>1</sup> => index), Array ()) called at [/Users/patrick/projects/sandwichboard/stats/modules/FrontController.php:143]
15. Piwik_FrontController→dispatch() called at [/Users/patrick/projects/sandwichboard/stats/index.php:55]

Fatal error: Call to a member function getTimestamp() on a non-object in /Users/patrick/projects/sandwichboard/stats/modules/Date.php on line 109
```

Adding another site makes the issue go away. Removing the site makes the error come back.

I was testing with the following API call, but it occurs for others as well

``

`

http://localhost/index.php?module=API&method=VisitsSummary.getVisits&idSite=all&period=day&date=last30&format=xml