catch the case that cowsay is broken (#76326)

* catch the case that cowsay is broken

fixes https://github.com/ansible/ansible/issues/72582

  add changelog
  raise Exception for broken cowsay
  add test for broken cowsay

Co-authored-by: Matthias Bernt <m.bernt@ufz.de>

changelogs/fragments/72592-catch-broken-cowsay.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - catch the case that cowsay is broken which would lead to missing output

lib/ansible/utils/display.py

@@ -219,7 +219,9 @@ class Display(metaclass=Singleton):
             try:
                 cmd = subprocess.Popen([self.b_cowsay, "-l"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                 (out, err) = cmd.communicate()
-                self.cows_available = {to_text(c) for c in out.split()}
+                if cmd.returncode:
+                    raise Exception
+                self.cows_available = {to_text(c) for c in out.split()}  # set comprehension
                 if C.ANSIBLE_COW_ACCEPTLIST and any(C.ANSIBLE_COW_ACCEPTLIST):
                     self.cows_available = set(C.ANSIBLE_COW_ACCEPTLIST).intersection(self.cows_available)
             except Exception:

test/units/utils/display/test_broken_cowsay.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+# Copyright (c) 2021 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+
+__metaclass__ = type
+
+
+from ansible.utils.display import Display
+from mock import MagicMock
+
+
+def test_display_with_fake_cowsay_binary(capsys, mocker):
+    mocker.patch("ansible.constants.ANSIBLE_COW_PATH", "./cowsay.sh")
+
+    def mock_communicate(input=None, timeout=None):
+        return b"", b""
+
+    mock_popen = MagicMock()
+    mock_popen.return_value.communicate = mock_communicate
+    mock_popen.return_value.returncode = 1
+    mocker.patch("subprocess.Popen", mock_popen)
+
+    display = Display()
+    assert not hasattr(display, "cows_available")
+    assert display.b_cowsay is None