
A bug in macOS 10.15.5 impacts bootable backups - chmaynard
https://bombich.com/blog/2020/05/27/bug-in-macos-10.15.5-impacts-bootable-backups-weve-got-you-covered
======
chmaynard
From the article:

The chflags() system call can no longer set the SF_FIRMLINK flag on a folder
on an APFS volume. Rather than fail with an error code that we would have
detected, it fails silently – it exits with a success exit status, but
silently fails to set the special flag ... Apple preaches that you should
always check your error codes, and we do – religiously. This bug slipped past
us for who knows how long because the system call exits with a success error
code ... It's hard to find kind words to express my feelings towards Apple
right now. Suffice it to say, though, I'm extremely disappointed that Apple
would introduce this kind of bug in a dot-release OS update. We've seen 5
major updates to Catalina now, we should expect to see higher quality than
this from an operating system.

~~~
wahern
Did setting SF_FIRMLINK ever succeed for real? Firmlinks are an APFS addition,
and AFAIU not only can't usercode directly create firmlinks, trying to set
SF_FIRMLINK with chflags is non-sensical, sort like trying to use chmod to set
the S_IFDIR bit on a regular file. Apple would hardly be the first OS to
silently ignore non-sensical flags in a bitfield; such problems and their
dilemmas have plagued Linux syscalls for years. Though if this is a _change_
of behavior--it previously always failed but now it doesn't--that's
problematic. Alternatively, if previously chflags seemed to work--st_flags
reflected the SF_FIRMLINK bit on subsequent stat, even if the inode wasn't
actually a firmlink--the change would be closer to a fix than a regression.
I'm more curious why you were trying to set it in the first place. Maybe I'm
misunderstanding.

~~~
devy
> Did setting SF_FIRMLINK ever succeed for real?

It should have been working fine right? Otherwise CCC team would have reported
this bug in the earlier release. As what Mike Bombich said in the original
post:

    
    
       The chflags() system call can no longer set the SF_FIRMLINK flag on a folder on an APFS volume. 
    

The keyword was "no longer".

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joshstrange
And this is why I'm not interested in touching the latest macOS unless I'm
forced to for work. I'm still on Mojave and doing just fine. Swift UI was the
only thing I was even close to missing but I haven't needed it yet thankfully.

~~~
skoskie
Stay there. This is the worst version of the OS since I started using it,
which was Tiger.

I’ve had to reboot twice today. It’s not finding the printer or other network
devices. Handoff and AirDrop stop working intermittently. It’s just a total
disaster.

~~~
darrmit
Ditto. Started with Tiger and this is just so far below the bar for previous
releases it’s almost unbearable. The SIP delays alone are bad enough, but the
random bugs with Bluetooth, Thunderbolt, and seemingly everything else make it
a chore to use my MacBook Pro.

Meanwhile, my iMac running Mojave is chugging along just fine and will
continue to until I absolutely can’t stand it anymore..

~~~
rayiner
Same here. I also started with Tiger. This will be the first Mac I flat out
return if 10.15.5 doesn't fix my KPs.

------
0x0
This is incredibly telling about the state of affairs in the macOS development
group. The bug was reported early for a beta (burning a technical incident
ticket, even) but still shipped in the final release.

At this point it feels like Darwin macOS can't be saved even when it shares
most of its code with Darwin iOS.

What will happen to the iOS app market space when macOS degrades so much that
developers can't use it anymore? (I refuse to believe serious developers would
put up with an iOS-ified/iPadOS-ified Xcode with the current UI paradigms in
those OSes)

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markandrewj
When I tried updating to 10.15.5 today, the update failed and dumped me into
system utilities. I was able to restore from my Time Machine backups luckily.
It's unfortunate that issues such as this are becoming the norm for MacOS.

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NKosmatos
I don’t understand why Apple (and other big companies) with all the resources
they’ve got, all these talented people and all this money, fail to provide
reliable, safe and useful updates for their products. Is it that difficult to
do proper quality checks and hear the feedback? I can see a trend the last
couple of years where updates/upgrades are going in the wrong direction...well
at least Apple is not in the same situation as Microsoft with their updates
and service packs ruining perfectly working systems.

~~~
jmull
Well, zero bugs in something as complicated as an OS release is not going to
happen. It is that difficult.

Not really trying to excuse Apple — probably they should have caught this one
and generally should have fewer bugs.

But the idea that an OS update is going to go out with no bugs is just not
going to happen.

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chmaynard
Why doesn't Apple embrace open source for the lower levels of macOS? If there
were a community of developers working together on APFS, for example, this bug
probably would have been found and fixed immediately.

~~~
musicale
Yeah, look like the last open source release was 10.15.3:

[https://opensource.apple.com](https://opensource.apple.com)

~~~
chmaynard
I don't see APFS there. Regardless, I doubt if there is a real community of
developers working on the Darwin code base. Contrast this with Swift on
GitHub, which is very welcoming project with a high level of developer
participation.

~~~
vaxman
Swift, like Objective C, is irrelevant outside of the Mac. If SwiftUI is
opensourced, that could change, but server-side Swift is done unless Apple
goes into competition with AWS, Azure and GCP.

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lonelappde
Is Time Machine or other backup tools affected too?

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guildmaster
Yes. Keep them coming.

