[THRIFT-3401] Nested collections emit Objective-C code that cannot compile

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Component/s: Cocoa - Compiler

Environment

OS X 10.9 and 10.10

• Assignee: Kevin Wooten
• Reporter: Steve Yegge
• Created: 28/Oct/15 19:51
• Updated: 20/Feb/21 15:27
• Resolved: 18/Mar/16 18:02

Description

Nested Thrift collections produce nested generics in Objective-C. Unfortunately, Objective-C generics do not appear to support type nesting.

For instance,

1: list<list<string>> foo

generates an Objective-C declaration like this

@property (strong, nonatomic) NSMutableArray<NSArray<NSString *>> * foo;

which results in an XCode compile error: Type argument 'NSArray<NSString *>' is neither an Objective-C object nor a block type

The only workaround is to edit the generated code to remove the nested type specifiers.

Until Objective-C supports nesting generic types, the Thrift cocoa compiler should limit the type nesting to at most one level – NSMutableArray<NSArray> is legal, for instance. Alternately, an easier solution might be to add a flag that disables the generation of generic types for cocoa.