Improve "changed" count flag

pyproject.toml

@@ -18,7 +18,7 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
-    "License :: CC0 1.0 Universal (CC0 1.0) Public Domain Dedication"
+    "License :: CC0 1.0 Universal (CC0 1.0) Public Domain Dedication",
 ]
 
 [tool.poetry.dependencies]

stow

@@ -33,12 +33,11 @@ from ansible.module_utils.basic import AnsibleModule
 
 
 STOW_CONFLICTS_MESSAGE_REGEX_BY_VERSION = {
-    '2.3.1': r'^\* existing target is neither a link nor a directory: (?P<target_path>.+)$',
+    '2.3.1': r'^\* existing target is neither a link nor a directory: (?P<link_path>.+)$',
     # pylint: disable-next=line-too-long
-    '2.4.0': r'^\* cannot stow (?P<link_path>.+) over existing target (?P<target_path>.+) since neither a link nor a directory and --adopt not specified$',
+    '2.4.0': r'^\* cannot stow (?P<package_path>.+) over existing target (?P<link_path>.+) since neither a link nor a directory and --adopt not specified$',
 }
 
-
 SUPPORTED_STOW_VERSIONS = list(STOW_CONFLICTS_MESSAGE_REGEX_BY_VERSION.keys())
 
 
@@ -171,14 +170,39 @@ def stow_has_conflicts(stow_version, module, package, cmd):
         conflict_match = conflict_re.match(sel.strip())
 
         if conflict_match:
-            conflicts.append(os.path.join(params['target'], conflict_match.group('target_path')))
+            conflicts.append(os.path.join(params['target'], conflict_match.group('link_path')))
 
     conff = ', '.join(f'"{f}"' for f in conflicts)
     msg = f'unable to stow package "{package}" to "{params["target"]}"; conflicted files: {conff}'
 
     return {'recoverable': True, 'message': msg, 'files': conflicts}
 
 
+def has_stow_changed_links(stow_output):
+    if stow_output.strip() == '':
+        return 0
+
+    n_linked = set()
+    link_re = re.compile(r'^LINK: (?P<link_path>.+) => (?P<package_path>.+)(?P<reverts> \(reverts previous action\))?$')
+
+    n_unlinked = set()
+    unlink_re = re.compile(r'^UNLINK: (?P<link_path>.+)$')
+
+    for sel in stow_output.split('\n'):
+        sel = sel.strip()
+
+        link_match = link_re.match(sel)
+        if link_match:
+            n_linked.add(link_match.group('link_path'))
+            continue
+
+        unlink_match = unlink_re.match(sel)
+        if unlink_match:
+            n_unlinked.add(unlink_match.group('link_path'))
+
+    return n_linked != n_unlinked
+
+
 def stow(stow_version, module, package, state):
     """Perform stow on a package against the filesystem.
 
@@ -230,17 +254,27 @@ def stow(stow_version, module, package, state):
         msg = f'execution of command "{cmd}" failed with error code {rc_}; output: "{se_}"'
         return {'error': True, 'message': msg}
 
-    return {'error': False, 'changed': se_ != ''}
+    return {'error': False, 'changed': has_stow_changed_links(se_)}
 
 
 def main():
     '''The module main routine.'''
 
     module = AnsibleModule(
         argument_spec={
-            'dir': {'required': True, 'type': 'str'},
-            'package': {'required': True, 'type': 'list'},
-            'target': {'required': False, 'type': 'str', 'default': os.environ.get('HOME')},
+            'dir': {
+                'required': True,
+                'type': 'str',
+            },
+            'package': {
+                'required': True,
+                'type': 'list',
+            },
+            'target': {
+                'required': False,
+                'type': 'str',
+                'default': os.environ.get('HOME'),
+            },
             'state': {
                 'required': True,
                 'type': 'str',

tests/ansible.cfg

@@ -1,3 +1,4 @@
 [defaults]
 
-interpreter_python=auto
+interpreter_python = auto_silent
+stdout_callback = debug

tests/stow.yml

@@ -7,4 +7,10 @@
       stow:
         state: '{{ state }}'
         package: foo
-        dir: '$HOME/package'
+        dir: '$HOME/package'
+      register: stowt
+
+    - name: 'fail if "changed" is greater than 0 when nothing has changed'
+      fail:
+        msg: 'task should not have changed anything'
+      when: stowt is changed and fail_if_changed == 'yes'

tests/test.sh

@@ -3,15 +3,15 @@
 set -e
 
 run_playbook() {
-    ansible-playbook -i hosts stow.yml --extra-vars "state=$1" -v
+    ansible-playbook -i hosts stow.yml --extra-vars "state=$1 fail_if_changed=$2" -v
 }
 
 # create the library directory and copy the module
-mkdir library
+mkdir -p library
 cp ../stow library
 
 # move the package to the home directory
-mv package ~
+cp -r package ~
 
 # run the playbook and stow the package
 figlet "state: present"
@@ -34,6 +34,8 @@ test -h "$HOME/.config/foo" && exit 1
 figlet "state: latest"
 run_playbook "present"
 run_playbook "latest"
+run_playbook "latest" "yes"
+run_playbook "latest" "yes"
 run_playbook "absent"
 
 # create a file that should conflict with the package