tox: envlist bugfixes

Change-Id: I17e807aa544f6fb45e82604f35c027fe1f86c2f9

roles/fetch-tox-output/tasks/main.yaml

@@ -24,9 +24,17 @@
   set_fact:
     envlist: "{{ tox_envlist.split(',') }}"
   when: tox_envlist is defined and tox_envlist != 'ALL' and tox_envlist
+# tox version <= 3.13.2 throws an exception if
+# tox -l is run and envlist is not set so set
+# failed_when: false for any version below that
+- name: Get tox version
+  command: "{{ tox_executable }} --version"
+  register: tox_version_output
 
 - name: Find all default environments
   command: "{{ tox_executable }} -l"
+  failed_when: "{{ tox_default_environments is failed and tox_version_output.stdout | regex_search('\\d+\\.\\d+\\.\\d+') is version('3.13.2', '>') }}"
+
   args:
     chdir: "{{ zuul_work_dir }}"
   register: tox_default_environments

roles/tox/tasks/main.yaml

@@ -61,6 +61,7 @@
     - name: Return file comments to Zuul
       when:
         - tox_inline_comments
+        - file_comments.file_comments is defined
         - file_comments.file_comments
       delegate_to: localhost
       zuul_return: