SwiftUI names are not demangled

[sindresorhus]

Platform

macOS

Environment

Production

Installed

Swift Package Manager

Version

8.24.0

Did it work on previous versions?

No

Steps to Reproduce

Look at this report: https://sindresorhus.sentry.io/share/issue/0e4faa9089734b2bbe498a1e876fb30e/

In the stack trace:

7SwiftUI4ViewRzlAA15ModifiedContentVyxAA16OnSubmitModifierVGAaBHPxAaBHD1__AfA0cH0HPyHCHCTm
7SwiftUI4ViewRzlAA15ModifiedContentVyxAA21_DefaultFocusModifierVGAaBHPxAaBHD1__AfA0cH0HPyHCHCTm

Expected Result

I expected them to be demangled.

Actual Result

They are not demangled.

Are you willing to submit a PR?

No

[philipphofmann]

Thanks for opening this. It might be related to #3081.

[Swatinem]

I dug into this a little bit, and it turns out that when you use Verbose Function Names, both of these are prefixed with get_witness_table , which is being generated right here:

https://github.com/apple/swift/blob/3caef440583aa16ff0164395899b6e87e234f427/lib/IRGen/GenReflection.cpp#L519-L522

Swifts own demangler does not recognize that, as is it does not start with a proper swift mangling prefix.
(Admittedly, our demangler is based on Swift 5.5.1 which is a bit out of date)

However, if I replace that with the proper prefix ($s), I get the following:

• <A>concrete protocol conformance ModifiedContent<A, OnSubmitModifier>protocol conformance ref (type's module) Viewdependent root protocol conformance #0 AViewconcrete protocol conformance OnSubmitModifierprotocol conformance ref (type's module) ViewModifier
• <A>concrete protocol conformance ModifiedContent<A, _DefaultFocusModifier>protocol conformance ref (type's module) Viewdependent root protocol conformance #0 AViewconcrete protocol conformance _DefaultFocusModifierprotocol conformance ref (type's module) ViewModifier

That is quite a mouthful, and TBH I have no idea what any of that means.

Long story short, the compiler has to output a proper swift symbol with the proper prefix for it to be demangled properly.

[Swatinem]

But it might also be related to #3081 as @philipphofmann mentioned, as its quite possible that we just end up trying to demangle the name of some static data table because we lack access to proper debug symbols.

[philipphofmann]

If I got it right @Swatinem, except from doing #3081 there isn't much we can do right now, except to wait for Apple to provide proper dSYMs for SwiftUI?

[Swatinem]

Indeed, we need to have a proper dSYM, otherwise its hard to move forward on any of this.