yum_versionlock: Fix entry matching (#4183)

As an input the module receives names of packages to lock.
Those never matched existing entries and therefore always reported
changes.

For compatibility yum is symlinked to dnf on newer systems,
but versionlock entries defer. Try to parse both formats.

Signed-off-by: Florian Achleitner <flo@fopen.at>

changelogs/fragments/4183-fix-yum_versionlock.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - "yum_versionlock - fix matching of existing entries with names passed to the module. Match yum and dnf lock format (https://github.com/ansible-collections/community.general/pull/4183)."

plugins/modules/packaging/os/yum_versionlock.py

@@ -17,7 +17,7 @@ description:
 options:
   name:
     description:
-      - Package name or a list of packages.
+      - Package name or a list of package names with optional wildcards.
     type: list
     required: true
     elements: str
@@ -74,10 +74,17 @@ state:
     sample: present
 '''
 
+import re
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.common.text.converters import to_native
 from fnmatch import fnmatch
 
+# on DNF-based distros, yum is a symlink to dnf, so we try to handle their different entry formats.
+NEVRA_RE_YUM = re.compile(r'^(?P<exclude>!)?(?P<epoch>\d+):(?P<name>.+)-'
+                          r'(?P<version>.+)-(?P<release>.+)\.(?P<arch>.+)$')
+NEVRA_RE_DNF = re.compile(r"^(?P<exclude>!)?(?P<name>.+)-(?P<epoch>\d+):(?P<version>.+)-"
+                          r"(?P<release>.+)\.(?P<arch>.+)$")
+
 
 class YumVersionLock:
     def __init__(self, module):
@@ -102,6 +109,15 @@ class YumVersionLock:
         self.module.fail_json(msg="Error: " + to_native(err) + to_native(out))
 
 
+def match(entry, name):
+    m = NEVRA_RE_YUM.match(entry)
+    if not m:
+        m = NEVRA_RE_DNF.match(entry)
+    if not m:
+        return False
+    return fnmatch(m.group("name"), name)
+
+
 def main():
     """ start main program to add/remove a package to yum versionlock"""
     module = AnsibleModule(
@@ -123,20 +139,20 @@ def main():
 
     # Ensure versionlock state of packages
     packages_list = []
-    if state in ('present'):
+    if state in ('present', ):
         command = 'add'
         for single_pkg in packages:
-            if not any(fnmatch(pkg.split(":", 1)[-1], single_pkg) for pkg in versionlock_packages.split()):
+            if not any(match(pkg, single_pkg) for pkg in versionlock_packages.split()):
                 packages_list.append(single_pkg)
         if packages_list:
             if module.check_mode:
                 changed = True
             else:
                 changed = yum_v.ensure_state(packages_list, command)
-    elif state in ('absent'):
+    elif state in ('absent', ):
         command = 'delete'
         for single_pkg in packages:
-            if any(fnmatch(pkg, single_pkg) for pkg in versionlock_packages.split()):
+            if any(match(pkg, single_pkg) for pkg in versionlock_packages.split()):
                 packages_list.append(single_pkg)
         if packages_list:
             if module.check_mode: