From e8347c2a758dc73108d4071b8a45b1b54da4ee9b Mon Sep 17 00:00:00 2001
From: Martijn Pieters <mj@zopatista.com>
Date: Wed, 8 Jan 2025 18:45:02 +0000
Subject: [PATCH] Avoid generating empty ImportFrom statements

- When emitting a `ImportFrom()` node, assert that the list of names
  is not empty, and address all places where this potentially could
  happen.
- Extend the `input_types_generator/test_filtering_names` test to
  include at least 1 enum so that it would trigger the assertion error
  if that enum is not included in the used inputs.
---
 ariadne_codegen/client_generators/client.py   | 26 ++++++++++---------
 .../client_generators/input_types.py          |  4 +--
 ariadne_codegen/codegen.py                    |  1 +
 .../test_filtering_names.py                   |  7 +++++
 4 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/ariadne_codegen/client_generators/client.py b/ariadne_codegen/client_generators/client.py
index 4c0831a5..8977a050 100644
--- a/ariadne_codegen/client_generators/client.py
+++ b/ariadne_codegen/client_generators/client.py
@@ -111,20 +111,22 @@ def __init__(
 
     def generate(self) -> ast.Module:
         """Generate module with class definition of graphql client."""
-        self._add_import(
-            generate_import_from(
-                names=self.arguments_generator.get_used_inputs(),
-                from_=self.input_types_module_name,
-                level=1,
+        if used_inputs := self.arguments_generator.get_used_inputs():
+            self._add_import(
+                generate_import_from(
+                    names=used_inputs,
+                    from_=self.input_types_module_name,
+                    level=1,
+                )
             )
-        )
-        self._add_import(
-            generate_import_from(
-                names=self.arguments_generator.get_used_enums(),
-                from_=self.enums_module_name,
-                level=1,
+        if used_enums := self.arguments_generator.get_used_enums():
+            self._add_import(
+                generate_import_from(
+                    names=used_enums,
+                    from_=self.enums_module_name,
+                    level=1,
+                )
             )
-        )
         for custom_scalar_name in self.arguments_generator.get_used_custom_scalars():
             scalar_data = self.custom_scalars[custom_scalar_name]
             for import_ in generate_scalar_imports(scalar_data):
diff --git a/ariadne_codegen/client_generators/input_types.py b/ariadne_codegen/client_generators/input_types.py
index 0a5797d3..ec609315 100644
--- a/ariadne_codegen/client_generators/input_types.py
+++ b/ariadne_codegen/client_generators/input_types.py
@@ -81,9 +81,9 @@ def generate(self, types_to_include: Optional[List[str]] = None) -> ast.Module:
         class_defs = self._filter_class_defs(types_to_include=types_to_include)
         self._generated_public_names = [class_def.name for class_def in class_defs]
 
-        if self._used_enums:
+        if used_imports := self.get_used_enums():
             self._imports.append(
-                generate_import_from(self.get_used_enums(), self.enums_module, 1)
+                generate_import_from(used_imports, self.enums_module, 1)
             )
 
         for scalar_name in self._used_scalars:
diff --git a/ariadne_codegen/codegen.py b/ariadne_codegen/codegen.py
index 6f964ea1..b613789c 100644
--- a/ariadne_codegen/codegen.py
+++ b/ariadne_codegen/codegen.py
@@ -29,6 +29,7 @@ def generate_import_from(
     names: List[str], from_: Optional[str] = None, level: int = 0
 ) -> ast.ImportFrom:
     """Generate import from statement."""
+    assert names, "Using ImportFrom with no names would produce invalid Python code"
     return ast.ImportFrom(
         module=from_, names=[ast.alias(n) for n in names], level=level
     )
diff --git a/tests/client_generators/input_types_generator/test_filtering_names.py b/tests/client_generators/input_types_generator/test_filtering_names.py
index 14106564..a38caa20 100644
--- a/tests/client_generators/input_types_generator/test_filtering_names.py
+++ b/tests/client_generators/input_types_generator/test_filtering_names.py
@@ -30,9 +30,15 @@
 )
 def test_generator_returns_module_with_filtered_classes(used_types, expected_classes):
     schema_str = """
+    enum EnumA {
+        VALUE1
+        VALUE2
+    }
+
     input InputA {
         valueAA: InputAA!
         valueAB: InputAB
+        valueEnumA: EnumA
     }
 
     input InputAA {
@@ -46,6 +52,7 @@ def test_generator_returns_module_with_filtered_classes(used_types, expected_cla
     input InputAB {
         val: String!
         valueA: InputA
+        valueEnumA: EnumA
     }
 
     input InputX {