User and developer outlook
Apple hopes -- and likely expects -- that most Mac App Store customers won't notice that anything has changed as they start installing sandboxed apps from the Mac App Store. For many niche apps that don't need access to any extras (think games and to-do list managers), that should indeed be the case; sandboxing those apps shouldn't have any tangible impact on the user experience.
But in other cases, developers may be forced to sacrifice features large and small to comply with Apple's security requirements. Flying Meat Software's popular image editor Acorn, for example, offers a clever shortcut for power users: When saving an image, merely changing the filename's extension automatically tells the app to adjust what format you're saving the file in. The sandboxed Mac App Store version of the app won't support that feature, Flying Meat's Gus Mueller told Macworld, because -- he believes -- of under-the-hood changes related to how Save dialog boxes work within the sandbox. Mueller stressed that he's not certain precisely why the feature doesn't work in the sandboxed version of Acorn, but he's been devoting his time to figuring out other, more pressing sandboxing issues, like getting the app's AppleScripts to work.
On the plus side, while Mueller had feared last November that Apple's sandboxing approach would break other Acorn features, like plug-in and screenshot support, "it looks like Apple built in some smarts that look for user intent with regards to" features like those.
Rich Siegel of Bare Bones Software spoke to Macworld about his concerns regarding sandboxing last November too, rattling off a long list of features in the company's popular text editor BBEdit that he feared might not be allowed going forward: multifile search and replace, text factory applications, multi-application automation using AppleScript or Automator, Open File by Name, disk browsers, live folder views in projects, SCM integration, bulk HTML tool operations (such as syntax check and site update), and lots of behind-the-scenes stuff such as scanning directories for ctags data. Back then, Siegel said he wasn't sure which features BBEdit would be able to continue to support once sandboxed.
And now that sandboxing is here, Siegel still isn't sure: "The question really remains wide open," he wrote in an email to Macworld. "With a technology like sandboxing, any feature changes are dictated by the underlying system; so we can't really know whether a given feature or behavior is going to work until we test it in the sandboxed environment." While Bare Bones knows that BBEdit features like its Unix command-line tools and privilege escalation when saving over root-owned files will never work in the sandbox, "there's a lot of testing to do" with other features in the software. And, of course, once Bare Bones identifies issues that don't work, Siegel says, "we have to decide whether to neuter the feature entirely or agitate with Apple for changes to the system to enable it to work."