The installer_test CI job is broken

[thufschmitt]

Describe the bug

https://github.com/NixOS/nix/runs/8187933590?check_suite_focus=true (and all . For some reason the sha256 in the generated install script differs from the hash of the tarball we get from cachix since last week.

It doesn't seem totally deterministic (a9af12e got merged three days ago and has a green CI), and seems to randomly affect both the Linux and MacOS tarballs.

Running diffoscope on a pair of offending tarballs shows a timestamp mismatch somewhere:

$ nix run p\#diffoscope nix-2.12.0pre20220905_df5159e-x86_64-darwin.tar.xz /nix/store/mcj4z3ggqzvlz44xsyixlins9d388zr9-nix-binary-tarball-2.12.0pre20220905_df5159e/*.tar.xz
--- nix-2.12.0pre20220905_df5159e-x86_64-darwin.tar.xz
+++ /nix/store/mcj4z3ggqzvlz44xsyixlins9d388zr9-nix-binary-tarball-2.12.0pre20220905_df5159e/nix-2.12.0pre20220905_df5159e-x86_64-darwin.tar.xz
├── nix-2.12.0pre20220905_df5159e-x86_64-darwin.tar
│ ├── file list
│ │ @@ -1,13 +1,13 @@
│ │ --rwxr-xr-x   0 root         (0) wheel        (0)     8665 2022-09-05 09:57:45.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install
│ │ --rwxr-xr-x   0 root         (0) wheel        (0)    32687 2022-09-05 09:57:45.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/create-darwin-volume.sh
│ │ --rwxr-xr-x   0 root         (0) wheel        (0)     6685 2022-09-05 09:57:45.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install-darwin-multi-user.sh
│ │ --rwxr-xr-x   0 root         (0) wheel        (0)     5368 2022-09-05 09:57:45.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install-systemd-multi-user.sh
│ │ --rwxr-xr-x   0 root         (0) wheel        (0)    28793 2022-09-05 09:57:45.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install-multi-user
│ │ --rw-r--r--   0 root         (0) wheel        (0)    20504 2022-09-05 09:57:45.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/.reginfo
│ │ +-rwxr-xr-x   0 root         (0) wheel        (0)     8665 2022-09-05 09:32:25.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install
│ │ +-rwxr-xr-x   0 root         (0) wheel        (0)    32687 2022-09-05 09:32:25.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/create-darwin-volume.sh
│ │ +-rwxr-xr-x   0 root         (0) wheel        (0)     6685 2022-09-05 09:32:25.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install-darwin-multi-user.sh
│ │ +-rwxr-xr-x   0 root         (0) wheel        (0)     5368 2022-09-05 09:32:25.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install-systemd-multi-user.sh
│ │ +-rwxr-xr-x   0 root         (0) wheel        (0)    28793 2022-09-05 09:32:25.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/install-multi-user
│ │ +-rw-r--r--   0 root         (0) wheel        (0)    20504 2022-09-05 09:32:25.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/.reginfo
│ │  drwxr-xr-x   0 root         (0) wheel        (0)        0 1970-01-01 00:00:01.000000 nix-2.12.0pre20220905_df5159e-x86_64-darwin/store/01mj3sckpsccjs2xxkk5g7785l9q768x-libcxxabi-11.1.0/

I presume the tarball is occasionally built twice at slightly different times in the CI pipeline (rather than being fetched from the cache the second time), causing the discrepancy. The logical fix seems to be to just reset the timestamps to make it reproducible

[thufschmitt]

Reopening since it seems that the error is striking again (https://github.com/NixOS/nix/actions/runs/3118058809/jobs/5057274066). Probably the fix wasn't complete