* fetchurl: fix and add extra KDE mirrors (#51480)
- The gwdg.de mirror has moved the relative path of its KDE tarballs
- Add new mirrors from Berkeley and MIT, which are on the list of officially supported mirrors
https://download.kde.org/extra/download-mirrors.html
* More KDE mirror touchups
- The official one is a redirect to HTTPS anyways, so go directly to HTTPS
- Add China USTC for Asian users
- Swap Finland university from FTP to HTTP
* fetchurl: keep one ftp KDE mirror
It would be nice to be able to track Nix requests. It's not trustworthy,
but can be helpful for stats and routing in HTTP logs.
Since `fetchurl` is used so widely, we should "magically" get a UA on
`fetchzip`, `fetchFromGitHub`, and other related fetchers.
Since `fetchurl` is only used for fixed-output derivations, this should
cause no mass rebuild.
User-Agent example: curl/7.57.0 Nixpkgs/18.03
Fixes#27406.
Commit 5d4efb2c816d2143f29cad8153faad1686557b2a added an assertion to `stopNest'
which requires it be correctly paired with `startNest'. `fetchurl' calls
`stopNest', but never calls `startNest'; the former calls are removed.
This typo was likely introduced by copy-pasting the error message from elsewhere and forgetting to change the text, during the MD5 deprecation process (#4491).
Deprecation warnings should not be used in Nixpkgs because they spam
innocent "nix-env -qa" users with (in this case) dozens of messages
that they can't do anything about.
This also reverts commit 2ca883338389b7ab995924a0cab0211993bdf1da.
downloads.sourceforge.net is the official way to download tarballs from
SourceForge. However, it is reported as unreliable due to SF's weird
load balancing system.
This commit gives the official mirror utmost priority, and will use
other configured mirrors (which may be temporary) as a fallback only
when the official one can't be reached/download fails/hangs.
References: NixOs/nixpkgs#16900
The two lines I removed technically assert the exact same thing, since `!a -> b`
is equivalent to `a || b`. So, I replaced the two lines with the more symmetric
form to make it clearer.
