pip - fix reporting changed for empty venv creation (#85556)

* Add correct empty venv creation handling

Makes the module exit with changed=True
when an empty venv is created with correct
module output

* Add tests for creating an empty venv

changelogs/fragments/85556-fix-pip-changed.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - pip - Fix pip module output so that it returns changed when the only operation is initializing a venv.

lib/ansible/modules/pip.py

@@ -608,7 +608,7 @@ def setup_virtualenv(module, env, chdir, out, err):
     err += err_venv
     if rc != 0:
         _fail(module, cmd, out, err)
-    return out, err
+    return out, err, cmd
 
 
 class Package:
@@ -741,11 +741,12 @@ def main():
 
         err = ''
         out = ''
+        venv_cmd = ''
 
         if env:
             if not os.path.exists(os.path.join(env, 'bin', 'activate')):
                 venv_created = True
-                out, err = setup_virtualenv(module, env, chdir, out, err)
+                out, err, venv_cmd = setup_virtualenv(module, env, chdir, out, err)
             py_bin = os.path.join(env, 'bin', 'python')
         else:
             py_bin = module.params['executable'] or sys.executable
@@ -811,6 +812,11 @@ def main():
             cmd.extend(to_native(p) for p in packages)
         elif requirements:
             cmd.extend(['-r', requirements])
+        elif venv_created and not name and not requirements:
+            # ONLY creating an empty venv
+            module.exit_json(changed=venv_created, cmd=venv_cmd, name=name, version=version,
+                             state=state, requirements=requirements, virtualenv=env,
+                             stdout=out, stderr=err)
         else:
             module.warn("No valid name or requirements file found.")
             module.exit_json(changed=False)

test/integration/targets/pip/tasks/pip.yml

@@ -213,6 +213,35 @@
     that:
       - "diff_case_check_mode is not changed"
 
+- name: ensure is a fresh venv
+  file:
+    state: absent
+    name: "{{ remote_tmp_dir }}/emptyvenv"
+
+- name: create an empty venv
+  pip:
+    name: []
+    virtualenv: "{{ remote_tmp_dir }}/emptyvenv"
+  register: empty_venv
+
+- name: check venv was created
+  file:
+    name: "{{ remote_tmp_dir }}/emptyvenv"
+  register: check_empty_venv_exists
+
+- name: try creating an empty venv so it isn't changed
+  pip:
+    name: []
+    virtualenv: "{{ remote_tmp_dir }}/emptyvenv"
+  register: second_empty_venv
+
+- name: assert that the venv was created and has no packages
+  assert:
+    that:
+      - empty_venv.changed
+      - not check_empty_venv_exists.changed
+      - not second_empty_venv.changed
+
 # ansible#23204
 - name: ensure is a fresh virtualenv
   file: