New -1728 error when opening applet from within DMG image file

Scripting Forums AppleScript | Mac OS X
#1

for some years, I have been distributing my run-only applet in read-only dmg images. Unbeknownst to me, some users have been opening the applet from within the dmg image: download the dmg; open the dmg; drag the applet’s icon to Dock; and click the Dock alias to open the applet. This has been working for those users for all those years.

I released a new version this month. A user made contact to complain of an error when they open the applet:

System Events got an error: Can’t get property list file
“MyApplet-v1.24: MyApplet.app:contents:Info.plist”.
(-1728)

In my testing, I have also seen this error:

System Events got an error: Can’t get property list file
“1C52474D-6A50-4C59-9007-0DE5321B89F2:d:MyApplet.app:
contents:Info plist”. (-1728)

I don’t know why the error is now sometimes showing what looks like a UUID. That string changes with each error.

I also get the error when the dmg image is set to “read-write” and the applet is not run-only. The error is the same on macOS 10.13 and 13.3.

The error is being reported when, very close to the start, System Events tries to get the copyright text at this point:

tell application "System Events"
	set My_copyright to value of property list item "NSHumanReadableCopyright" of contents of property list file bundle_file
	set My_version to value of property list item "CFBundleShortVersionString" of contents of property list file bundle_file
end tell

“bundle_file” is a string containing the path to the info.plist file inside the applet.

The info.plist file has not changed for years with the exception of a new version number and date with each release.

I do not get the error if I create the DMG file on a Mac running an old version of OS X e.g. 10.13. I always get the error if I create the DMG in macOS 13.3.1. That is the only change I can find between the two versions of the applet.

Can anyone suggest what changed in macOS 13.3 which could be causing the error when accessing files in a dmg image ?

Thanks.

#2

How are you getting the path to the Info.plist within the app’s bundle?
I noticed that the path in the first error message has a space before the app’s name:

“MyApplet-v1.24: MyApplet.app:contents:Info.plist”

#3

Krioni, thanks.

I noticed that the path in the first error message has a space before the app’s name:

Thanks, that was my mistake in copying and pasting from the error dialog into my post. There is no space in the path.

I will add a test to catch cases where the applet is started from inside the dmg. I’ll also add a graphic to the dmg window reminding users to drag the applet to an appropriate location.

My main interest is what changed in macOS 13.3 which makes it difficult for System Events to get property list items out of mounted images. I’ll do some more testing.

#4

UPDATE: So, have tested new blank images, some read-only, on Ventura 13.3 and have had no errors. Now, can’t find a way to trigger the error – except with the dmg image I created to release the applet. Suggests I did something unusual back then – can’t imagine what. I’ll have to re-release the applet.

UPDATE 2: Found the cause of the problem. I created the dmg image in which to release the applet with “case-sensitive” on. Did another test now and got the same error. Lesson learned.