baseldap: Handle missing parent objects properly in *-find commands

The find_entries function in ipaldap does not differentiate between
a LDAP search that returns error code 32 (No such object) and LDAP
search returning error code 0 (Success), but returning no results.

In both cases errors.NotFound is raised. In turn, LDAPSearch
commands interpret NotFound exception as no results.

To differentiate between the cases, a new error EmptyResult
was added, which inherits from NotFound to preserve the compatibility
with the new code.

This error is raised by ipaldap.find_entries in case it is performing
a search with and the target dn does not exist.

https://fedorahosted.org/freeipa/ticket/4659

Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipalib/errors.py

@@ -1329,6 +1329,21 @@ class PosixGroupViolation(ExecutionError):
     errno = 4030
     format = _('This is already a posix group and cannot be converted to external one')
 
+class EmptyResult(NotFound):
+    """
+    **4031** Raised when a LDAP search returned no results.
+
+    For example:
+
+    >>> raise EmptyResult(reason='no matching entry found')
+    Traceback (most recent call last):
+      ...
+    EmptyResult: no matching entry found
+
+    """
+
+    errno = 4031
+
 class BuiltinError(ExecutionError):
     """
     **4100** Base class for builtin execution errors (*4100 - 4199*).

ipalib/plugins/baseldap.py

@@ -1995,8 +1995,10 @@ class LDAPSearch(BaseLDAPCommand, crud.Search):
                 time_limit=options.get('timelimit', None),
                 size_limit=options.get('sizelimit', None)
             )
-        except errors.NotFound:
+        except errors.EmptyResult:
             (entries, truncated) = ([], False)
+        except errors.NotFound:
+            self.api.Object[self.obj.parent_object].handle_not_found(*args[:-1])
 
         for callback in self.get_callbacks('post'):
             truncated = callback(self, ldap, entries, truncated, *args, **options)

ipapython/ipaldap.py

@@ -1527,7 +1527,7 @@ class LDAPClient(object):
                     break
 
         if not res and not truncated:
-            raise errors.NotFound(reason='no such entry')
+            raise errors.EmptyResult(reason='no matching entry found')
 
         return (res, truncated)