NixOS hydra build failure due to JS file conflict

[benaryorg]

Describe the bug
Upstream hydra reports a failure and the reasons seems to be that the minified jQuery files get installed twice.

To Reproduce
Steps to reproduce the behavior:

1. for now I have only seen this happen on the NixOS Hydra instance

Expected behavior
hydra_unstable should build on hydra.nixos.org.

Screenshots
Here's the relevant log bit:

[…]
/nix/store/bblyj5b3ii8n6v4ra0nb37cmi3lf8rz9-coreutils-9.3/bin/install -c -m 644  static/js/jquery/jquery-3.4.1.min.js static/js/jquery/jquery-ui-1.10.4.min.js '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/jquery'
'./static/js/flot/jquery.min.js' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/flot/jquery.min.js'
'./static/js/flot/LICENSE.txt' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/flot/LICENSE.txt'
'./static/js/flot/Makefile' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/flot/Makefile'
'./static/js/flot/NEWS.md' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/flot/NEWS.md'
'./static/js/flot/PLUGINS.md' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/flot/PLUGINS.md'
'./static/js/flot/README.md' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/flot/README.md'
'./static/js/jquery/jquery-3.4.1.min.js' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/jquery/jquery-3.4.1.min.js'
'./static/js/jquery/jquery-ui-1.10.4.min.js' -> '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/jquery/jquery-ui-1.10.4.min.js'
cp: cannot create regular file '/nix/store/kwdjj8isn1khycrblmhawkl4ssiavylg-hydra-2023-11-17/libexec/hydra/root/static/js/jquery/jquery-ui-1.10.4.min.js': File exists
[…]

As you can see the first line runs install to place the jQuery files there.
Then the second to last line seems to run a regular cp to copy the files, which due to the previous install fails.

Here's the rough timeline of the build failures in case this helps somehow.

Hydra Server:

Please fill out this data as well as you can, but don't worry if you can't -- just do your best.

• OS and version: ?
• Hydra 0.1.20230823.00d3087
• Version of Nix Hydra is built against: ?
• nix 2.17.0

Additional context

Since there seems to be a copy copying over these files already I think there's either a superfluous copy somewhere, or the install invocation (presumably originating here) is too much.
I don't know which one is the one that's supposed to run though.