Transitioning to ARC Release Notes missing important caveat on exceptions

Originator:jens.ayton
Number:rdar://10329810 Date Originated:2011-10-22
Status:Open Resolved:
Product:Documentation Product Version:10.7 SDK
Classification:Enhancement Reproducible:n/a
 
By default, the compiler does not emit exception cleanup code for Objective-C, causing leaks, unless the -fobjc-arc-exceptions flag is passed.  This is documented and well justified in the ARC semantic specification (http://clang.llvm.org/docs/AutomaticReferenceCounting.html#misc.exceptions), but not in the Transitioning to ARC Release Notes.

Since developers transitioning to clang are likely to be reading the latter – especially since the clang release notes are not found in Xcode’s or developer.apple.com’s documentation search – it would be useful to have this information there.

(Using exceptions with no intention of crashing is unusual for Objective-C code, but not deprecated or truly esoteric. Handling unusual-yet-valid and surprising cases strikes me as the most important task of a transitioning guide.)

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