In a thread titled “Avoid Dispatch Global Concurrent Queues” [1], Quinn links to a video from WWDC 2015 Session 718, “Building Responsive and Efficient Apps with GCD”. However, this video is not available from the Apple Developer Videos site; only a half dozen or so videos from 2015 are available. This same issue of the missing video came up about five years ago, when Quinn stated that the video had been mistakenly removed but had been restored. Now it’s gone again. :sad_face: Could this video be restored again, or at least its transcript? While I understand that Apple is focused on Swift concurrency, I need to maintain some Objective-C code that uses GCD, and in tracking down some performance issues, I would like to better understand the tradeoffs in the existing code and make improvements where I can. I don’t have the resources to reimplement the code in Swift right now. (More generally, why can't Apple just leave all these videos online indefinitely, for historical purposes at least? Couldn't the ones deemed “old and misleading” just be tagged with a banner like the legacy documentation has?) [1] I like to think of these valuable threads as “Quinn Technical Notes”; I have a page in my Notes app that holds links to the ones I’ve found.

I've been experimenting with the new low-level Swift API for XPC (XPCSession and XPCListener). The ability to send and receive Codable messages is an appealing alternative to making an @objc protocol in order to use NSXPCConnection from Swift — I can easily create an enum type whose cases map onto the protocol's methods. But our current XPC code validates the incoming connection using techniques similar to those described in Quinn's "Apple Recommended" response to the "Validating Signature Of XPC Process" thread. I haven't been able to determine how to do this with XPCListener; neither the documentation nor the Swift interface have yielded any insight. The Creating XPC Services article suggests using Xcode's XPC Service template, which contains this code: let listener = try XPCListener(service: serviceName) { request in request.accept { message in performCalculation(with: message) } } The apparent intent is to inspect the incoming request and decide whether to accept it or reject it, but there aren't any properties on IncomingSessionRequest that would allow the service to make that decision. Ideally, there would be a way to evaluate a code signing requirement, or at least obtain the audit token of the requesting process. (I did notice that a function xpc_listener_set_peer_code_signing_requirement was added in macOS 14.4, but it takes an xpc_listener_t argument and I can't tell whether XPCListener is bridged to that type.) Am I missing something obvious, or is there a gap in the functionality of XPCListener and IncomingSessionRequest?

Our product includes a sudo plugin so we can apply user-defined policies to manage privileged access to command line programs. We’ve been getting reports where the plugin sometimes doesn't get invoked and the sudo command falls back to its default behavior. This seems to only be happening intermittently, but when the issue does occur, this message appears in the Console: Library Validation failed: Rejecting '/usr/local/libexec/sudo/<our_plugin>.so' (Team ID: <OURTEAMID>, platform: no) for process 'sudo(<pid>)’ (Team ID: N/A, platform: yes), reason: mapping process is a platform binary, but mapped file is not I recall a previous discussion of this message (that I can’t locate now), which explained that although the host process has library validation disabled, the code flow raises an error anyway, so that the host process can detect it and bypass the validation to load the plugin. It looks like that's what sudo is doing: it has the private entitlement com.apple.private.security.clear-library-validation and makes the appropriate system call when the plugin initially fails to load [1] — but apparently this isn't working reliably for our sudo plugin. We’ve observed that restarting the Mac generally resolves the issue, at least for a while. This resembles the “classic symptom of a code signing oddity” where the signature is cached and the Mach-O image is rewritten rather than replaced (as documented in Updating Mac Software). But our software uses an Installer package for updates as well as initial installation, and the Installer is documented as not having this issue, so I believe the problem lies somewhere else. I’m running out of ideas; are there any other avenues I should investigate? Thanks for any help. [1] This is described in an article called "About com.apple.private.security.clear-library-validation"; I can't link to it directly from the developer forums, but it can easily be found by searching for the title.

Our company changed its name as a result of a merger, and the development group responsible for our mobile apps decided to migrate from our "legacy" Apple developer account to a new account associated with the new company name. I found this out last Friday when the notification step in the build script for our Mac applications stopped working — the notification server accepts the request but never responds; we were using the --wait flag with notarytool, and as a result it hangs indefinitely. Apparently our old developer account was deactivated unexpectedly, and while it's been temporarily turned back on to allow the mobile apps team to finish migrating their apps, the notarization step continues to hang. I haven't yet tried using the new team account, because my product requires an Endpoint Security entitlement, which is associated with the old Team ID. The long-term answer is probably to re-apply for a new entitlement, but that took over a month the last time we did this, and of course we were scheduled to release a product update in two weeks. At the moment we're dead in the water. Are there any other options to get us going again? (I considered opening a code-level support request, but as this issue isn't exactly "code-level", I was worried that would be a waste of time and/or money.)