feat: handle deprecation for NullBooleanField

django_codemod/visitors/__init__.py

@@ -18,7 +18,11 @@
     IsSafeUrlTransformer,
 )
 from .lru_cache import LRUCacheTransformer
-from .models import ModelsPermalinkTransformer, OnDeleteTransformer
+from .models import (
+    ModelsPermalinkTransformer,
+    NullBooleanFieldTransformer,
+    OnDeleteTransformer,
+)
 from .os_utils import AbsPathTransformer
 from .paginator import QuerySetPaginatorTransformer
 from .postgres_fields import (
@@ -60,6 +64,7 @@
     "JSONModelFieldTransformer",
     "LRUCacheTransformer",
     "ModelsPermalinkTransformer",
+    "NullBooleanFieldTransformer",
     "OnDeleteTransformer",
     "QuerySetPaginatorTransformer",
     "RenderToResponseTransformer",

django_codemod/visitors/base.py

@@ -4,6 +4,7 @@
 
 from libcst import (
     Arg,
+    AssignEqual,
     Attribute,
     BaseExpression,
     BaseSmallStatement,
@@ -16,6 +17,7 @@
     Name,
     RemovalSentinel,
     RemoveFromParent,
+    SimpleWhitespace,
 )
 from libcst import matchers as m
 from libcst.codemod import CodemodContext, ContextAwareTransformer
@@ -45,6 +47,33 @@ def import_from_matches(node: ImportFrom, module_parts: Sequence[str]) -> bool:
     return m.matches(node, m.ImportFrom(module=module_matcher(module_parts)))
 
 
+def make_kwarg(name, value):
+    """Helper to add simple kwarg to a function call.
+
+    By default, libCST adds some spaces around the equal sign:
+
+        func(name = value)
+
+    This helper builds it without spaces:
+
+        func(name=value)
+    """
+    return Arg(
+        value=value,
+        keyword=Name(
+            value=name,
+        ),
+        equal=AssignEqual(
+            whitespace_before=SimpleWhitespace(
+                value="",
+            ),
+            whitespace_after=SimpleWhitespace(
+                value="",
+            ),
+        ),
+    )
+
+
 class BaseRenameTransformer(BaseDjCodemodTransformer, ABC):
     """Base class to help rename or move a declaration."""
 

django_codemod/visitors/models.py

@@ -1,4 +1,4 @@
-from typing import Optional, Union
+from typing import Optional, Sequence, Union
 
 from libcst import (
     Arg,
@@ -20,9 +20,21 @@
 from libcst import matchers as m
 from libcst.codemod.visitors import AddImportsVisitor
 
-from django_codemod.constants import DJANGO_1_9, DJANGO_1_11, DJANGO_2_0, DJANGO_2_1
+from django_codemod.constants import (
+    DJANGO_1_9,
+    DJANGO_1_11,
+    DJANGO_2_0,
+    DJANGO_2_1,
+    DJANGO_3_1,
+    DJANGO_4_0,
+)
 from django_codemod.utils.calls import find_keyword_arg
-from django_codemod.visitors.base import BaseDjCodemodTransformer, module_matcher
+from django_codemod.visitors.base import (
+    BaseDjCodemodTransformer,
+    BaseFuncRenameTransformer,
+    make_kwarg,
+    module_matcher,
+)
 
 
 class ModelsPermalinkTransformer(BaseDjCodemodTransformer):
@@ -190,3 +202,22 @@ def leave_Call(self, original_node: Call, updated_node: Call) -> BaseExpression:
             )
             return updated_node.with_changes(args=updated_args)
         return super().leave_Call(original_node, updated_node)
+
+
+class NullBooleanFieldTransformer(BaseFuncRenameTransformer):
+    """Replace `NullBooleanField` by `BooleanField` with `null=True`."""
+
+    deprecated_in = DJANGO_3_1
+    removed_in = DJANGO_4_0
+
+    rename_from = "django.db.models.NullBooleanField"
+    rename_to = "django.db.models.BooleanField"
+
+    def update_call_args(self, node: Call) -> Sequence[Arg]:
+        return (
+            *node.args,
+            make_kwarg(
+                "null",
+                Name(value="True"),
+            ),
+        )

tests/visitors/test_models.py

@@ -2,6 +2,7 @@
 
 from django_codemod.visitors.models import (
     ModelsPermalinkTransformer,
+    NullBooleanFieldTransformer,
     OnDeleteTransformer,
 )
 from tests.visitors.base import BaseVisitorTest
@@ -344,3 +345,41 @@ def get_name(self):
                     return 'World'
         """
         self.assertCodemod(before, after)
+
+
+class TestNullBooleanFieldTransformer(BaseVisitorTest):
+
+    transformer = NullBooleanFieldTransformer
+
+    def test_noop_models(self) -> None:
+        before = after = """
+            from django.db import models
+
+            class MyThing(models.Model):
+                is_active = models.BooleanField()
+        """
+        self.assertCodemod(before, after)
+
+    def test_noop_fields(self) -> None:
+        before = after = """
+            from django.db.models import BooleanField, Model
+
+            class MyThing(Model):
+                is_active = BooleanField()
+        """
+        self.assertCodemod(before, after)
+
+    def test_simple_substitution(self) -> None:
+        before = """
+            from django.db import models
+
+            class MyThing(models.Model):
+                is_active = models.NullBooleanField()
+        """
+        after = """
+            from django.db import models
+
+            class MyThing(models.Model):
+                is_active = models.BooleanField(null=True)
+        """
+        self.assertCodemod(before, after)