Summary:
As explained in the code comment, these reports are generally
non-actionable at best and false positives at worst:
skip reporting for constant dereference (eg null dereference) if the source of the null value is
not on the path of the access, otherwise the report will probably be too confusing: the actual
source of the null value can be obscured as any value equal to 0 (or the constant) can be
selected as the candidate for the trace, even if it has nothing to do with the error besides
being equal to the value being dereferenced
Reviewed By: da319
Differential Revision: D28350193
fbshipit-source-id: 0cd76d252
Summary: Similar as for NSDictionary, nil issues for array literals are caught because of the additional load instruction in the frontend, and we leave modelling arrayWithObjects:count: for later.
Reviewed By: jvillard
Differential Revision: D28442767
fbshipit-source-id: a2f0d4dbf
Summary: Similar as for other collections we leave modelling setWithObjects:count: and initWithObjects:count for later.
Reviewed By: skcho
Differential Revision: D28473361
fbshipit-source-id: 4bf57035a
Summary: `dictionaryWithObjectsForKeysCount` is a bit more complicated as we need to know if an element of an array is nil. Leaving it for later.
Reviewed By: skcho
Differential Revision: D28413859
fbshipit-source-id: 7b5116de8
Summary: There is no need to model anything, Pulse is able to catch nil insertion into NSDictionary literals because the frontend dereferences keys and values during the translation of NSDictionary literals
Reviewed By: jvillard
Differential Revision: D28383176
fbshipit-source-id: 01a064daf
Summary:
`mutableDictionary[key] = value`, crashes if key is nil, however, if value is nil, any object corresponding to a key will be removed from the dictionary.
Under the hood, `NSMutableDictionary.setObject:forKeyedSubscript:` is called by `mutableDictionary[key] = value`.
Reviewed By: ezgicicek
Differential Revision: D28288789
fbshipit-source-id: e4e1c4288
Summary:
Warn if either an object or a key is nil for NSMutableDictionary setObject:forKey:.
Next steps: introduce new special issue type and model more collections
Reviewed By: ezgicicek
Differential Revision: D28189382
fbshipit-source-id: 1697829ee
Summary: Added a new issue type for sending a message to nil when its return type is non-POD. To distinguish these issues from other nullptr dereference issues, we extend the `MustBeValid` attribute to contain the reason of why an address must be valid. For now a reason can only have `SelfOfNonPODReturnMethod` as it's value, but in the future we will use it for other nullability issue types, such as nil insertion into collections.
Reviewed By: jvillard
Differential Revision: D27762333
fbshipit-source-id: 689e5a431
Summary: To support objc nil messaging for unknown function calls we prune `self` to be positive in the `normal` specification and add additional specification to handle nil case.
Reviewed By: skcho
Differential Revision: D27360757
fbshipit-source-id: 119999b30
Summary: In ObjC, when a method is called on nil, there is no NPE, the method is actually not called and the return value is 0/false/nil. There is an exception in the case where the return type is non-POD. In that case it's UB and we want to report an error.
Reviewed By: jvillard
Differential Revision: D26815687
fbshipit-source-id: 8126414ab
Summary: We were missing a part of the trace if it was going through a nil summary as the invalidation was set in the nil summary. Instead of creating a fresh value for return in the nil summary {self=0}{return=0}, we return self {self=0}{return=self}. This way we keep all the information about invalidation in the trace.
Reviewed By: jvillard
Differential Revision: D26871098
fbshipit-source-id: 6eb175e68
Summary: When a method is called in ObjC on nil, there is no NPE, the method is actually not called and the return value is 0/false/nil. (There is an exception in the case where the return type is non-POD. In that case it's UB. This will be addressed later). To implement this behaviour we add additional summary to ObjC instance methods {self = 0} {return = 0}. We also want to make sure that inferred summary will not be used in we call a method on nil, hence, we add a path condition {self > 0} to get a contradiction when needed.
Reviewed By: jvillard
Differential Revision: D26664187
fbshipit-source-id: cdac2a5bb
Summary: Added some basic examples for Objective-C we want to address next in pulse nullptr dereference analysis. In particular, we should not get a `nil` dereference error when we call a method on `nil`, except if the method returns a non-POD (Plain Old Data) type.
Reviewed By: ezgicicek
Differential Revision: D26053402
fbshipit-source-id: 66f4600c3
Jules Villard
Daiva Naudziuniene