Editing of update site URL after activating it leads to wrong file URLs

[skalarproduktraum]

When activating an update site, then making a change to the site URL, the base URL of the site gets updated, but the file list doesn't. This leads to the updater not finding the files then and bailing out.

Reproduction:

• activate SciView update site
• changing the URL from https://sites.imagej.net/SciView/ to https://sites.imagej.net/SciView-Unstable/
• close the dialog
• apply changes

Expected result: Files should be downloaded from the Unstable update site

Actual result: Updater tries to download files with the Unstable base URL, but file names from the regular update site, leading to failure.

[imagejan]

The URLs for the listed update sites are provided here i the list-of-update-sites repository.

So the solution to this issue should be to disallow changing the URLs of listed update sites, and only allow editing those sites that were added manually.

[skalarproduktraum]

Well, partially, because this might also screw the manually added ones.

On a somewhat related note: If the updater encounters a 404, it has nevertheless already deleted the file it intends to replace, so this issue might actually lead to a non-working Fiji install.