Internal error aString!-nil

[john beardsworth]

A plug-in that works correctly on PC is generating an error on the Mac. The plug-in adds a menu command and launches a dialog box, but running it on the Mac produces this error dialog:

Internal error has occurred - Invalid parameter not satisfying :  aString!-nil .

After that error occurs, the PlugIn Manager is unavailable (similar error message) and only becomes accessible after a restart. The plugin is shown to be running, but any subsequent attempt to run the menu item causes the error.

To eliminate the menu command's code, I have removed almost all the code, but the same problem happened. I have also replaced its code with code from another plug-in that does work on the Mac. Again no solution. I have also changed the LrToolkitIdentifier and plug-in name.

By now, I recognise enough of the messages to suspect that this is an odd one. Any thoughts?

John

[escouten]

[Deleted private e-mail response...]

[escouten]

John sent me a copy of his plug-in and I've just had a chance to look at it.

The problem was that his LibraryMenuItem.lua file was encoded as UTF-8 and had the UTF-8 byte-order-mark (EF BB BF) at the start of the file.

Though Lightroom's APIs are expressed in terms of UTF-8, that is a choice made by the Lightroom team. Lua itself has no knowledge of UTF-8 and doesn't know what to do with these odd bytes at the start of the file.

Solution: Re-save the file as plain ol' ASCII.

[john beardsworth]

Well spotted Eric.I've now isolated the problem to using the most recent version of ExtendScript ToolKit on the Mac and not noticing ESTK3's new preference for the UTF-8 signature. Its default is "Always write signature" which does exactly what it says on the tin - saving the file with the default preference results in the error, switching it to "Never" resolves it.

The Mac-PC thing is not a case of LR handling UTF-8 encoded files differently on different OS's. It's simply the result of initially writing the plug-in an earlier version of ETSK which doesn't have this preference.

Thanks for your help

John