[Bug]: [runner] Exported Bash functions corrupt `/dstack/profile`

[un-def]

Steps to reproduce

Perhaps there is an easier way to reproduce it, but this is the actual setup in which the issue was discovered:

1. Configure a Slurm cluster as a dstack backend. Important: nodes must use a distro where /bin/sh is Bash (readlink -f /bin/sh → /usr/bin/bash). We deployed a cluster using GCP's cluster-toolkit, which uses Rocky Linux.
2. Export a Bash function function via profile, e.g., add to ~/.bash_profile:

   say_hi() { echo hi; }
   export -f say_hi

   The image used by GCP's cluster-toolkit has Lmod preinstalled, which exports its functions.
3. Submit a run with image based on a distro where /bin/sh is Bash, e.g., Fedora:

   type: task
   image: fedora
   commands:
     - printenv | grep BASH_FUNC_

4. SSH into the run
5. grep BASH_FUNC_ /dstack/profile

---

The reason why we need a distro with sh→bash symlink is that (d)ash (used by, e.g., Debian/Ubuntu) removes invalid variables (BASH_FUNC_<name>%% format with % is intentionally used by Bash; such a name is not a valid shell identifier) while Bash in POSIX mode bypass them to child processes (and, apparently, even source them). With the Slurm backend, we have 3 sh calls in the chain:

• batch script shebang
• srun sh -c ...
• JobSpec.commands generated from shell + commands where shell defaults to /bin/sh when image is set

Actual behaviour

Run commands output:

BASH_FUNC_ml%%=() {  eval $($LMOD_DIR/ml_cmd "$@")
BASH_FUNC_which%%=() {  ( alias;
BASH_FUNC_say_hi%%=() {  echo hi
BASH_FUNC_module%%=() {  eval $($LMOD_CMD bash "$@") && eval $(${LMOD_SETTARG_CMD:-:} -s sh)

ssh run-name output:

Warning: Permanently added '[slurm-mainnodeset-0]:10022' (ED25519) to the list of known hosts.
-bash: export: `BASH_FUNC_which%%=() {  ( alias;
 eval ${which_declare} ) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot $@
}': not a valid identifier
-bash: export: `BASH_FUNC_ml%%=() {  eval $($LMOD_DIR/ml_cmd "$@")
}': not a valid identifier
-bash: export: `BASH_FUNC_say_hi%%=() {  echo hi
}': not a valid identifier
-bash: export: `BASH_FUNC_module%%=() {  eval $($LMOD_CMD bash "$@") && eval $(${LMOD_SETTARG_CMD:-:} -s sh)
}': not a valid identifier

grep BASH_FUNC_ /dstack/profile:

export BASH_FUNC_which%%='() {  ( alias;
export BASH_FUNC_ml%%='() {  eval $($LMOD_DIR/ml_cmd "$@")
export BASH_FUNC_say_hi%%='() {  echo hi
export BASH_FUNC_module%%='() {  eval $($LMOD_CMD bash "$@") && eval $(${LMOD_SETTARG_CMD:-:} -s sh)

Expected behaviour

No response

dstack version

0.21.1

Server logs

Additional information

No response