I have ObjectiveC programs built with Xcode 10.3 and distributed as a package to install on macOS 10.12 to latest Monterey. I am planning to write a new program in Swift language and add it to the package. I noticed that some other Apps install libraries such as libSwiftCore.dylib in some paths and use. Should I also install libraries such as libSwiftCore.dylib in some path and use it?

Yesterday night, altool was working as usual. Today, 9-July-2020, something has happened that is making altool unusual. Seeing the following errors: 1 package(s) were not uploaded because they had problems: /var/folders/mr/jn3hv6vd0336jzdx2f_4859r0000gp/T/22F0A966-FAE9-46CA-98C0-52310EF97E62/qtcorefw.itmsp - Error Messages: Communication error. Please use diagnostic mode to check connectivity. You need to have outbound access to TCP port 443. An exception has occurred: java.security.DigestException: partial digests not returned Could not connect to Apple's web service. 2020-07-09 11:39:25.771 altool[3382:275147] * Error: Unable to notarize app. 2020-07-09 11:39:25.771 altool[3382:275147] * Error: code -18000 (Communication error. Please use diagnostic mode to check connectivity. You need to have outbound access to TCP port 443.) 2020-07-09 11:39:25.771 altool[3382:275147] * Error: code -18000 (An exception has occurred: java.security.DigestException: partial digests not returned) 2020-07-09 11:39:25.771 altool[3382:275147] * Error: code -18000 (Could not connect to Apple's web service.)

I noticed a crash report. This is not reproducible in my environment. The report mentions that as a port leak. How to detect and prevent such port leaks? Extracts from the crash report: OS Version: Mac OS X 10.15.7 (19H2) ... Crashed Thread: 8 Exception Type: EXCBADINSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Exception Note: EXCCORPSENOTIFY Termination Signal: Illegal instruction: 4 Termination Reason: Namespace SIGNAL, Code 0x4 Terminating Process: exc handler [156] Application Specific Information: BUG IN CLIENT OF LIBDISPATCH: Unable to allocate reply port, possible port leak Thread 8 Crashed: 0 libdispatch.dylib 0x00007fff68cfdf75 dispatchmachsendandwaitforreply.cold.6 + 29 1 libdispatch.dylib 0x00007fff68ce4cf4 dispatchmachsendandwaitforreply + 1630 2 libdispatch.dylib 0x00007fff68ce4d4e dispatchmachsendwithresultandwaitforreply + 50 3 libxpc.dylib 0x00007fff68f6c846 xpcconnectionsendmessagewithreplysync + 238 4 com.apple.CoreFoundation 0x00007fff2ecac083 _78-[CFPrefsPlistSource sendRequestNewDataMessage:toConnection:retryCount:error:]blockinvoke + 22 5 com.apple.CoreFoundation 0x00007fff2ecb3779 CFPREFERENCESISWAITINGFORSYSTEMCFPREFSD + 74 6 com.apple.CoreFoundation 0x00007fff2ecabfdf -[CFPrefsPlistSource sendRequestNewDataMessage:toConnection:retryCount:error:] + 672 7 com.apple.CoreFoundation 0x00007fff2ecabd0e _50-[CFPrefsPlistSource alreadylockedrequestNewData]blockinvoke + 197 8 com.apple.CoreFoundation 0x00007fff2ec6d726 -[CFXPreferences withConnectionForRole:performBlock:] + 36 9 com.apple.CoreFoundation 0x00007fff2ecabbee -[CFPrefsPlistSource alreadylockedrequestNewData] + 332 10 com.apple.CoreFoundation 0x00007fff2ec916a4 copyValueForKey + 193 11 com.apple.CoreFoundation 0x00007fff2ec915c7 -[CFPrefsPlistSource copyValueForKey:] + 45 12 com.apple.CoreFoundation 0x00007fff2ec91587 66-[CFXPreferences copyValueForKey:identifier:user:host:container:]blockinvoke + 32 13 com.apple.CoreFoundation 0x00007fff2ec697d7 -[CFXPreferences(SourceAdditions) withSourceForIdentifier:user:byHost:container:cloud:perform:] + 795 14 com.apple.CoreFoundation 0x00007fff2ec914ef -[CFXPreferences copyValueForKey:identifier:user:host:container:] + 184 15 com.apple.CoreFoundation 0x00007fff2ec913f5 _CFPreferencesCopyValueWithContainer + 113 ...

I could see only WWDC videos from 2015 or so in the Developer app. How to see the old videos? For example, after much search about XPC, I landed on to this page: https://developer.apple.com/videos/play/wwdc2013/702/ But contents could not be accessed. Getting this: Safari can’t open the page “​devstreaming.apple.com/videos/wwdc/2013/70 2xfx2xmlrics5pyrjfwu2m/702/702.pdf?dl=1” because Safari can’t find the server “devstreaming.apple.com”. Basically, I am looking for videos to learn about the best practices for XPC. Another topic I am interested is about how to trust or untrust a URLSession. I could not find a suitable WWDC video on this. Another topic I am interested to learn is Authorizations (setAuthRef). Any pointers?