And secondly, that hypothetical could well be using broken software too. We really don’t know how bad the PDF’s ABBY produces are, but as someone who owned this scanner and the software, it’s fairly obvious that the software is barely maintained.
It really isn’t Apple’s fault if someone else is producing bad files that they happened to previously tolerate, especially if that somebody isn’t maintaining their software.
But by this logic, no software other than those that Apple sells you directly (their own or through the MAS) is "supported software". If Apple makes a change and all of them break rendering it useless of anyone using software not bought from them, would you still be making this same apology?
ABBY hasn’t updated their software for Big Sur, i.e. ABBY themselves say it hasn’t been updated yet and is not supported by them on Big Sur.
That’s what unsupported means. It has nothing to do with whether Apple supports it.
I open it with preview. It opens fine. I close it and open it again. It opens fine.
I open it a third time and make a small arrow pointing to something and save it (as I would with ANY OTHER PDF).
It breaks.
I'm not using ABBYY. I've never heard of it. It's not on my system. It's just a PDF file that I got sent.
Now what?
I think it is. Preview used to correctly handle the thing, and now it doesn't. Users cannot be expected to inspect the raw PS code of their PDFs to determine standards compliance. What they can do is assume that something that works yesterday, and appears to work today, is in fact working.
The PDFs didn't change, the application did. It's the application's fault.
If you have compatible behavior that you remove, it's on you to alert the user of the reduced functionality.
But, there is no evidence yet that they removed anything.
It’s quite possible (I’d say likely) that ABBY’s PDFs were corrupt all along.
Preview may have tolerated them not because of a special feature which was then removed, but because it happened not to depend on correctness before.
In this case, Apple wouldn’t have been in a position to even know about the problem.
You know who would? ABBY, who have had free access to Big Sur for months. You’d think that even cursory testing at their end would have shown this problem.
They have had months to fix it, months to work with Apple on the issue, any months to publicize it it really is Apple’s fault.
Even if ABBY does have a bug and fixes it then people will still have a bunch of older documents they will want to read.
It's not clear if the issue is caused by the PDF files produced by ABBYY, or if the issue is also present in other OCR'ed PDF files.
In either case, Preview shouldn't silently corrupt the file. It could display an error saying that it was unable to save the file, or a warning that some data couldn't be saved, so that the user can check if the file still works for them after saving.
It’s not clear what’s causing the problem, but verifying correctness of programs is not a solved computer science problem.
PostScript was a stack machine with included operators which implemented a set of vector graphics commands. PDF has a similar rendering pipeline, but it renders a set of primitives described directly in the document -- there is no virtual machine involved.
The PDF that FineReader made worked properly. The one that Preview made didn't.
