QEMU: Files shipped by packages in `/run` are not present in test VMs

[OddBloke]

e.g. mysql-9.3 ships /run/mysqld but applying this patch:

diff --git a/mysql-9.3.yaml b/mysql-9.3.yaml
index 8dba98d25..b70a742fc 100644
--- a/mysql-9.3.yaml
+++ b/mysql-9.3.yaml
@@ -364,6 +364,8 @@ test:
         - make
         - glibc-dev
   pipeline:
+    - runs: |
+        test -e /run/mysqld
     - uses: test/tw/ldd-check
       with:
         extra-library-paths: "/usr/lib/private"

has no effect on, e.g. the Docker runner but causes the tests to fail with the QEMU runner:

2025/06/30 13:46:25 ERRO Failed to run command "/bin/sh -c 'set -ex\n[ -d '\\''/home/build'\\'' ] || mkdir -p '\\''/home/build'\\''\ncd '\\''/home/build'\\''\ntest -e /run/mysqld\n\nexit 0'" as "root": Process exited with status 1

and, indeed, /run is empty:

2025/06/30 13:46:25 INFO debugging command /bin/sh -c cd /home/build && exec /bin/sh
wolfi-vm:~# ls /run/
wolfi-vm:~# exit 1

[smoser]

@a-crate , fyi. related to var/run somewhat.

generally, I think packaged files in /run is just wrong.

[a-crate]

generally, I think packaged files in /run is just wrong.

Agreed, programs should do mkdir -p /run/app on startup. All data in /run is ephemeral, which is why there is a tmpfs mounted on /run at VM startup (which is the cause of this).

If we absolutely must package directories in /run for some reason we should also include a systemd-tmpfiles snippet to create /run/app inside of the tmpfs. IMO this is not really a bug in melange, /run will be a tmpfs in a VM running systemd with default settings, so melange is accurately representing the environment. It's a bug in our packages.