They’re still A Thing for App Store apps I think, but:
- using App Store for Xcode was historically very painful and ~nobody who uses Xcode daily downloads it from MAS
- it never worked ~that well~ for Xcode anyway - apart from the big download sizes, the problem with Xcode and the bundled SDKs is that they’re all approximately trillion little text files, and it’s not unheard of to wait longer for codesign (technically unxip) verification than for the download itself, which negates the user-facing benefits of delta upgrades for many users.
Xcode is so painful. I had to install it on mojave for some command line program dependency that demanded xcode be installed. Ok, lets try installing xcode via the command line. Turns out that did not install whatever was in the xcode suite that this tool depended on so I needed the web download. Problem was, I am on mojave. It took way to long to dig up the appropriate download link that was compatible. Then of course like all large web downloads from apple, I had to babysit it and restart the download when it failed every couple hundred mb.
Then extract the xip (requires double the space) then wait forever for it to verify. One of the small things I do not miss after quitting being an iPhone dev.
I always use MAS to install my production Xcode, specifically because it lets me have small updates.
I've been doing this for as long as it's been available there as a developer at Apple, in my own startup, and in my current role as well. Never had a problem with it.
I'm pretty sure mas-cli [https://github.com/mas-cli/mas] is abandonware. It hasn't received any meaningful updates in almost 2 years and most of its features are broken
That might have been what happened for me, except I give up and sudo rm -rf it, leaving MAS in a confused state while I go download the dmg/xip directly.
Upgrades are in place for Xcode. Your theory would only make (the most minimal of) sense for someone having multiple copies of Xcode, but in that case would be irrelevant to delta updates
