Fix unstable_autoreleasesafe in objc2-foundation

Author: madsmtm

objc2-foundation/src/macros.rs

@@ -80,10 +80,17 @@ macro_rules! object {
         // TODO: Consider T: Debug bound
         impl<$($t $(: $b)?),*> ::core::fmt::Debug for $name<$($t),*> {
             fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
-                use $crate::{INSObject, INSString};
-                ::objc2::rc::autoreleasepool(|pool| {
-                    ::core::fmt::Debug::fmt(self.description().as_str(pool), f)
-                })
+                use ::objc2::MessageReceiver;
+                use ::alloc::borrow::ToOwned;
+                use $crate::{INSObject, INSString, NSObject};
+                // "downgrading" to  NSObject and calling `to_owned` to work
+                // around `f` and Self not being AutoreleaseSafe.
+                // TODO: Fix this!
+                let this: &NSObject = unsafe { &*self.as_raw_receiver().cast() };
+                let s = ::objc2::rc::autoreleasepool(|pool| {
+                    this.description().as_str(pool).to_owned()
+                });
+                ::core::fmt::Debug::fmt(&s, f)
             }
         }
     };

objc2-foundation/src/string.rs

@@ -5,6 +5,7 @@ use core::slice;
 use core::str;
 use std::os::raw::c_char;
 
+use alloc::borrow::ToOwned;
 use objc2::ffi;
 use objc2::msg_send;
 use objc2::rc::{autoreleasepool, AutoreleasePool};
@@ -119,7 +120,11 @@ unsafe impl INSCopying for NSString {
 
 impl fmt::Display for NSString {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        autoreleasepool(|pool| fmt::Display::fmt(self.as_str(pool), f))
+        // The call to `to_owned` is unfortunate, but is required to work
+        // around `f` not being AutoreleaseSafe.
+        // TODO: Fix this!
+        let s = autoreleasepool(|pool| self.as_str(pool).to_owned());
+        fmt::Display::fmt(&s, f)
     }
 }