Darwin: `pytest` executed from `nix develop` fails due to /tmp being a symlink

[booxter]

$ nix develop

$ pytest
[...]
--------------------------------------------------------------------------- Captured stderr call ---------------------------------------------------------------------------
hint: Using 'master' as the name for the initial branch. This default branch name
hint: is subject to change. To configure the initial branch name to use in all
hint: of your new repositories, which will suppress this warning, call:
hint:
hint: 	git config --global init.defaultBranch <name>
hint:
hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
hint: 'development'. The just-created branch can be renamed via this command:
hint:
hint: 	git branch -m <name>
To /tmp/nix-shell.jYPQBd/tmpb4jndzb7/nixpkgs/remote
 * [new branch]      HEAD -> master
Switched to a new branch 'pull/363128/merge'
To /tmp/nix-shell.jYPQBd/tmpb4jndzb7/nixpkgs/remote
 * [new branch]      pull/363128/merge -> pull/363128/merge
warning: unknown setting 'sandbox-build-dir'
error: the path '"/tmp"' is a symlink; this is not allowed for the Nix store and its parent directories
========================================================================= short test summary info ==========================================================================
FAILED tests/test_rev.py::test_rev_command - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impure', '--raw',...
FAILED tests/test_rev.py::test_rev_command_without_nom - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impur...
FAILED tests/test_rev.py::test_rev_only_packages_does_not_trigger_an_eval - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command...
FAILED tests/test_pr.py::test_pr_ofborg_eval - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impure', '--raw...
FAILED tests/test_pr.py::test_pr_local_eval - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impure', '--raw'...
FAILED tests/test_pr.py::test_pr_local_eval_missing_nom - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impu...
FAILED tests/test_pr.py::test_pr_github_action_eval - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impure',...
FAILED tests/test_pr.py::test_pr_local_eval_without_nom - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impu...
FAILED tests/test_wip.py::test_wip_command - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impure', '--raw',...
FAILED tests/test_wip.py::test_wip_only_packages_does_not_trigger_an_eval - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command...
FAILED tests/test_wip.py::test_wip_command_without_nom - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command', 'eval', '--impur...
FAILED tests/test_pr.py::test_pr_only_packages_does_not_trigger_an_eval - subprocess.CalledProcessError: Command '['nix', '--extra-experimental-features', 'nix-command',...
=========================================================== 12 failed, 5 passed, 1 skipped in 116.45s (0:01:56) ============================================================

And indeed, on Darwin it's a symlink:

(ins)bash-5.2$ ls -ld /tmp
lrwxr-xr-x 1 root wheel 11 Aug 16 14:44 /tmp -> private/tmp

With the following patch, it still fails in a similar fashion:

diff --git a/tests/conftest.py b/tests/conftest.py
index e0f8164..2e79089 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -222,6 +222,7 @@ class Helpers:
 
             # Disable substituters and sandboxing for tests
             os.environ["NIX_CONFIG"] = f"""
+allow-symlinked-store = true
 substituters =
 connect-timeout = 0
 sandbox = false

$ pytest
[...]
* [new ref]         a1d68fa803874a775c51a113750d25260ef3115b -> refs/nixpkgs-review/1
Preparing worktree (detached HEAD a1d68fa)
warning: unknown setting 'sandbox-build-dir'
error:
       … while calling the 'listToAttrs' builtin
         at /Users/ihrachyshka/src/nixpkgs-review/nixpkgs_review/nix/evalAttrs.nix:52:1:
           51|
           52| listToAttrs (concatMap getProperties attrs)
             | ^
           53|

       … while calling the 'concatMap' builtin
         at /Users/ihrachyshka/src/nixpkgs-review/nixpkgs_review/nix/evalAttrs.nix:52:14:
           51|
           52| listToAttrs (concatMap getProperties attrs)
             |              ^
           53|

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: path '//tmp' is a symlink
https://github.com/NixOS/nixpkgs/pull/363128 failed to build: nix --extra-experimental-features nix-command no-url-literals --system aarch64-darwin eval --nix-path nixpkgs=/tmp/nix-shell.jYPQBd/tmpj7bvs70i/cache/nixpkgs-review/pr-363128/nixpkgs nixpkgs-overlays=/tmp/nix-shell.jYPQBd/tmpl71lgrpa --json --impure --no-allow-import-from-derivation --expr (import /Users/ihrachyshka/src/nixpkgs-review/nixpkgs_review/nix/evalAttrs.nix { attr-json = /tmp/nix-shell.jYPQBd/tmpgpai3bki; }) failed to run, /tmp/nix-shell.jYPQBd/tmpgpai3bki was stored inspection

(I've noticed warning: unknown setting 'sandbox-build-dir' message also shown in the output, but not sure if it's relevant.)

[Mic92]

Mhm. I think we could resolve the tempdir with an absolute path before running pytest?