From fa0bccf6a1f09c0118b1609aadd10f85927f5edb Mon Sep 17 00:00:00 2001
From: Rick Elrod <rick@elrod.me>
Date: Tue, 13 Apr 2021 10:27:52 -0500
Subject: [PATCH] [module_utils.distro] Fall back to bundled (#74229)

Change:
- When a "distro" package exists in PYTHONPATH but isn't what we expect,
  fall back to our own vendored one and use it. This prevents a
  traceback if someone has some random thing that provides "distro" but
  isn't actually the "distro" library we need.

Test Plan:
- new tests

Tickets:
- Fixes #74228

Signed-off-by: Rick Elrod <rick@elrod.me>

* nuke playbook test file

Signed-off-by: Rick Elrod <rick@elrod.me>

* test fixes

Signed-off-by: Rick Elrod <rick@elrod.me>
---
 .../fragments/nonstandard-distro-fallback.yml |  2 ++
 lib/ansible/module_utils/distro/__init__.py   | 10 ++++++++
 .../targets/module_utils_distro/aliases       |  1 +
 .../targets/module_utils_distro/meta/main.yml |  2 ++
 .../targets/module_utils_distro/runme.sh      | 24 +++++++++++++++++++
 5 files changed, 39 insertions(+)
 create mode 100644 changelogs/fragments/nonstandard-distro-fallback.yml
 create mode 100644 test/integration/targets/module_utils_distro/aliases
 create mode 100644 test/integration/targets/module_utils_distro/meta/main.yml
 create mode 100755 test/integration/targets/module_utils_distro/runme.sh

diff --git a/changelogs/fragments/nonstandard-distro-fallback.yml b/changelogs/fragments/nonstandard-distro-fallback.yml
new file mode 100644
index 00000000000..b4aa515e7b7
--- /dev/null
+++ b/changelogs/fragments/nonstandard-distro-fallback.yml
@@ -0,0 +1,2 @@
+minor_changes:
+  - module_utils distro - when a 'distro' package/module is in PYTHONPATH but isn't the real 'distro' package/module that we expect, gracefully fall back to our own bundled distro.
diff --git a/lib/ansible/module_utils/distro/__init__.py b/lib/ansible/module_utils/distro/__init__.py
index 25b148a1484..52c5344109a 100644
--- a/lib/ansible/module_utils/distro/__init__.py
+++ b/lib/ansible/module_utils/distro/__init__.py
@@ -32,15 +32,25 @@ _BUNDLED_METADATA = {"pypi_name": "distro", "version": "1.5.0"}
 
 
 import sys
+import types
 
 try:
     import distro as _system_distro
 except ImportError:
     _system_distro = None
+else:
+    # There could be a 'distro' package/module that isn't what we expect, on the
+    # PYTHONPATH. Rather than erroring out in this case, just fall back to ours.
+    # We require more functions than distro.id(), but this is probably a decent
+    # test that we have something we can reasonably use.
+    if not hasattr(_system_distro, 'id') or \
+       not isinstance(_system_distro.id, types.FunctionType):
+        _system_distro = None
 
 if _system_distro:
     distro = _system_distro
 else:
     # Our bundled copy
     from ansible.module_utils.distro import _distro as distro
+
 sys.modules['ansible.module_utils.distro'] = distro
diff --git a/test/integration/targets/module_utils_distro/aliases b/test/integration/targets/module_utils_distro/aliases
new file mode 100644
index 00000000000..0b4d548e4d9
--- /dev/null
+++ b/test/integration/targets/module_utils_distro/aliases
@@ -0,0 +1 @@
+shippable/posix/group3
\ No newline at end of file
diff --git a/test/integration/targets/module_utils_distro/meta/main.yml b/test/integration/targets/module_utils_distro/meta/main.yml
new file mode 100644
index 00000000000..1810d4bec98
--- /dev/null
+++ b/test/integration/targets/module_utils_distro/meta/main.yml
@@ -0,0 +1,2 @@
+dependencies:
+  - setup_remote_tmp_dir
diff --git a/test/integration/targets/module_utils_distro/runme.sh b/test/integration/targets/module_utils_distro/runme.sh
new file mode 100755
index 00000000000..e5d3d05333d
--- /dev/null
+++ b/test/integration/targets/module_utils_distro/runme.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -eux
+
+# Ensure that when a non-distro 'distro' package is in PYTHONPATH, we fallback
+# to our bundled one.
+new_pythonpath="$OUTPUT_DIR/pythonpath"
+mkdir -p "$new_pythonpath/distro"
+touch "$new_pythonpath/distro/__init__.py"
+
+export PYTHONPATH="$new_pythonpath:$PYTHONPATH"
+
+# Sanity test to make sure the above worked
+set +e
+distro_id_fail="$(python -c 'import distro; distro.id' 2>&1)"
+set -e
+grep -q "AttributeError:.*has no attribute 'id'" <<< "$distro_id_fail"
+
+# ansible.module_utils.common.sys_info imports distro, and itself gets imported
+# in DataLoader, so all we have to do to test the fallback is run `ansible`.
+ansirun="$(ansible -i ../../inventory -a "echo \$PYTHONPATH" localhost)"
+grep -q "$new_pythonpath" <<< "$ansirun"
+
+rm -rf "$new_pythonpath"