collection: Provide additional info about collection name restriction (#65250)

Fixes: #65151

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/collection_error_fix.yml

@@ -0,0 +1,2 @@
+minor_changes:
+- Provides additional information about collection namespace name restrictions (https://github.com/ansible/ansible/issues/65151).

lib/ansible/galaxy/collection.py

@@ -454,7 +454,10 @@ def validate_collection_name(name):
     if AnsibleCollectionRef.is_valid_collection_name(collection):
         return name
 
-    raise AnsibleError("Invalid collection name '%s', name must be in the format <namespace>.<collection>." % name)
+    raise AnsibleError("Invalid collection name '%s', "
+                       "name must be in the format <namespace>.<collection>. "
+                       "Please make sure namespace and collection name contains "
+                       "characters from [a-zA-Z0-9_] only." % name)
 
 
 @contextmanager

lib/ansible/utils/collection_loader.py

@@ -474,7 +474,7 @@ class AnsibleCollectionRef:
     @staticmethod
     def is_valid_collection_name(collection_name):
         """
-        Validates if is string is a well-formed collection name (does not look up the collection itself)
+        Validates if the given string is a well-formed collection name (does not look up the collection itself)
         :param collection_name: candidate collection name to validate (a valid name is of the form 'ns.collname')
         :return: True if the collection name passed is well-formed, False otherwise
         """