Xcode 7 Analyzer Fails to Recognize Method call on Dynamically-generated Class Object

Originator:justatheory
Number:rdar://21488883 Date Originated:2015-06-22
Status:Open Resolved:
Product:Xcode Product Version:7.0 beta (7A120f)
Classification:Developer Tools Reproducible:Always
 
Summary:
I have code like this in a class that has been working great on in Xcode 6 and earlier:

    id lm = NSClassFromString(@"CLLocationManager");
    if (lm && [lm locationServicesEnabled]) { … }

Xcode 7 reports this as deprecated with this message:

'locationServicesEnabled' is deprecated: first deprecated in iOS 4.0

However, that deprecation is for the locationServicesEnabled instance property, but this code is calling the +locationServicesEnabled class method, which is *not* deprecated.

Steps to Reproduce:
1. Paste this code into an app:

    id lm = NSClassFromString(@"CLLocationManager");
    if (lm && [lm locationServicesEnabled]) NSLog(@"YES");

2. Build the app.


Expected Results:
No warnings.

Actual Results:
Got warning:

  'locationServicesEnabled' is deprecated: first deprecated in iOS 4.0

Version:
Version 7.0 beta (7A120f)

Notes:


Configuration:
Occurs in Xcode 7 beta 1 (7A120f), but not Xcode 6 or earlier.

Attachments:

Comments

David Wheeler 07-Jul-2015 10:56 AM

So then I can call CLLocationManager class methods on lm? 

Class lm = NSClassFromString(@"CLLocationManager");
return lm && [lm locationServicesEnabled];

I would not have expected that, since locationServicesEnabled is a class method on CLLocationManager, not on Class.

By justatheory at July 7, 2015, 5:56 p.m. (reply...)

Apple Developer Relations 29-Jun-2015 03:15 PM

Hello David,

This is a follow-up regarding regarding Bug ID# 21488883.

This issue behaves as intended based on the following:

You call 'locationServicesEnabled' on 'id', so does a global lookup assumes that 'id' is likely an instance of CLLocationManager. Since you know you are getting a Class object and not an instance, change the code to:

Class lm = NSClassFromString(@"CLLocationManager");

Please update your bug report to let us know if this is still an issue for you.

By justatheory at July 7, 2015, 5:43 p.m. (reply...)

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