SR-5557: Fix NSRegularExpression errors with invalid pattern

[spevans]

• The error dictionary in CFRegularExpression was failing with the
  error key being a CFSTR inside an array so initialiase it outside
  of the array.

I removed the _nsObject as I think throwing the error dictionary is more useful as it gave a better error message when stringified.

Should a description be added to the error dictionary to eliminate the '(null)'?

[ianpartridge]

I probably haven't had enough coffee but I don't quite follow this one... Why does it make a difference whether it's an array of CFStringRef or a CFStringRef inside an array of CFTypeRef?

[spevans]

When CFSTR("NSInvalidValue") was declared directly inside the array it would crash CFHash, which is the actual fix.

I don't think the CFStringRef v CFTypeRef makes much difference here except that CFTypeRef seems to be the correct type for a key based on other code I looked at.

I think we will need either @parkera or @phausler to validate this fix.

[ianpartridge]

Yes you're right. I imagine this code is unchanged from Darwin so maybe there's some other factors involved.

[spevans]

Yes, although it did actually crash corelibs-foundation on macOS as well, which makes even less sense!

[phausler]

The problem previously with the key was because CFSTR in swift-corelibs does not use the builtin but instead uses an inline address of. That hack won't work with c arrays.

Overall this change looks reasonable to me.

[spevans]

Thats good to know. I did a quick audit of CSTR in CoreFoundation and noticed a few places where it is used in arrays so I'll add a PR soon to fix those cases

[ianpartridge]

@swift-ci please test and merge

[spevans]

@ianpartridge This looks to have failed due to an unrelated swift test failing, can you retry?

[ianpartridge]

@swift-ci please test and merge