pylint: Fix unnecessary-lambda-assignment

https://pylint.pycqa.org/en/latest/user_guide/messages/convention/unnecessary-lambda-assignment.html:
> Used when a lambda expression is assigned to variable rather than
defining a standard function with the "def" keyword.

https://peps.python.org/pep-0008/#programming-recommendations:
> Always use a def statement instead of an assignment statement that
binds a lambda expression directly to an identifier:
def f(x): return 2*x
f = lambda x: 2*x
The first form means that the name of the resulting function object is
specifically ‘f’ instead of the generic ‘<lambda>’. This is more useful
for tracebacks and string representations in general. The use of the
assignment statement eliminates the sole benefit a lambda expression can
offer over an explicit def statement (i.e. that it can be embedded
inside a larger expression)

Fixes: https://pagure.io/freeipa/issue/9278
Signed-off-by: Stanislav Levin <slev@altlinux.org>
Reviewed-By: Stanislav Levin <slev@altlinux.org>

ipapython/install/core.py

@@ -415,7 +415,11 @@ class Configurable(six.with_metaclass(abc.ABCMeta, object)):
     def __runner(self, pending_state, running_state, exc_handler):
         self.__transition(pending_state, running_state)
 
-        step = lambda: next(self.__gen)
+        def step_next():
+            return next(self.__gen)
+
+        step = step_next
+
         while True:
             try:
                 step()
@@ -440,9 +444,13 @@ class Configurable(six.with_metaclass(abc.ABCMeta, object)):
                 yield
             except BaseException:
                 exc_info = sys.exc_info()
-                step = lambda: self.__gen.throw(*exc_info)
+
+                def step_throw():
+                    return self.__gen.throw(*exc_info)
+
+                step = step_throw
             else:
-                step = lambda: next(self.__gen)
+                step = step_next
 
     def _handle_exception(self, exc_info):
         assert not hasattr(super(Configurable, self), '_handle_exception')

ipaserver/plugins/idrange.py

@@ -426,7 +426,8 @@ class idrange_add(LDAPCreate):
     def pre_callback(self, ldap, dn, entry_attrs, attrs_list, *keys, **options):
         assert isinstance(dn, DN)
 
-        is_set = lambda x: (x in entry_attrs) and (entry_attrs[x] is not None)
+        def is_set(x):
+            return entry_attrs.get(x) is not None
 
         # This needs to stay in options since there is no
         # ipanttrusteddomainname attribute in LDAP
@@ -685,11 +686,13 @@ class idrange_mod(LDAPUpdate):
                           '`ipa help idrange` for more information')
             )
 
-        is_set = lambda x: (x in entry_attrs) and (entry_attrs[x] is not None)
-        in_updated_attrs = lambda x:\
-            (x in entry_attrs and entry_attrs[x] is not None) or\
-            (x not in entry_attrs and x in old_attrs
-                and old_attrs[x] is not None)
+        def is_set(x):
+            return entry_attrs.get(x) is not None
+
+        def in_updated_attrs(x):
+            return is_set(x) or (
+                x not in entry_attrs and old_attrs.get(x) is not None
+            )
 
         # This needs to stay in options since there is no
         # ipanttrusteddomainname attribute in LDAP

ipatests/test_ipalib/test_frontend.py

@@ -211,7 +211,9 @@ class test_Command(ClassChecker):
                 lambda arg: arg,
                 'default_from'
         )
-        normalizer = lambda value: value.lower()
+
+        def normalizer(value):
+            return value.lower()
 
         class example(self.cls):
             takes_options = (

ipatests/test_ipalib/test_parameters.py

@@ -73,8 +73,7 @@ class test_DefaultFrom(ClassChecker):
         o = self.cls(callback, *keys)
         assert read_only(o, 'callback') is callback
         assert read_only(o, 'keys') == keys
-        lam = lambda first, last: first[0] + last
-        o = self.cls(lam)
+        o = self.cls(lambda first, last: first[0] + last)
         assert read_only(o, 'keys') == ('first', 'last')
 
         # Test that TypeError is raised when callback isn't callable:
@@ -108,7 +107,8 @@ class test_DefaultFrom(ClassChecker):
         o = self.cls(stuff, 'aye', 'bee', 'see')
         assert repr(o) == "DefaultFrom('aye', 'bee', 'see')"
 
-        cb = lambda first, last: first[0] + last
+        def cb(first, last):
+            return first[0] + last
 
         o = self.cls(cb)
         assert repr(o) == "DefaultFrom('first', 'last')"
@@ -293,7 +293,9 @@ class test_Param(ClassChecker):
         )
 
         # Test that default_from gets set:
-        call = lambda first, last: first[0] + last
+        def call(first, last):
+            return first[0] + last
+
         o = self.cls('my_param', default_from=call)
         assert type(o.default_from) is parameters.DefaultFrom
         assert o.default_from.callback is call

ipatests/test_util.py

@@ -81,7 +81,8 @@ class test_Fuzzy:
         assert inst.test is None
         assert isinstance(inst.re, pattern_type)
 
-        t = lambda other: other > 500
+        def t(other):
+            return other > 500
 
         inst = self.klass(test=t)
         assert inst.regex is None
@@ -97,7 +98,9 @@ class test_Fuzzy:
 
     def test_repr(self):
         s = 'Fuzzy(%r, %r, %r)'
-        t = lambda other: 0.0 <= other <= 1.0
+
+        def t(other):
+            return 0.0 <= other <= 1.0
 
         inst = self.klass()
         assert repr(inst) == s % (None, None, None)
@@ -129,7 +132,9 @@ class test_Fuzzy:
         assert (self.klass(type=int) == 18) is True
         assert (self.klass(type=(int, str)) == '18') is True
 
-        t = lambda other: other.endswith('bar')
+        def t(other):
+            return other.endswith('bar')
+
         assert (self.klass(test=t) == 'foobar') is True
         assert (self.klass(test=t, type=unicode) == b'foobar') is False
         assert (self.klass(test=t) == 'barfoo') is False

pylintrc

@@ -74,7 +74,6 @@ disable=
     super-init-not-called,
     undefined-loop-variable,
     unnecessary-lambda,
-    unnecessary-lambda-assignment,
     unused-argument,
     useless-else-on-loop,
     bad-continuation,