Here is more detail for those who are interested. There are two reasons I can think of to call alias on a local pdf file
- make a link to the pdf
- use the pdf as the src for an img tag (like including a .png image)
Use 1 seems to be a valid reason to call alias on a pdf, it did not work before, but would now work with the change. Note, there are a variety of OPL problems which have had links to external pdfs, and the links almost invariably break over time. If they had been local links where the pdf file had come with the problem, they would still work.
Use 2 is a wash because it fails no matter what (a tag of <img src="myfile.pdf"> doesn't work). So I don't think we need PGalias to throw an error in that situation.