Fix multipart body arrays (#938)

As described in #692 arrays of files are not handled correctly, if they
are part of multipart/form-data. This is fixed in this PR by letting
`to_multipart` return a `List[Tuple[str, Any]]` instead of a `Dict[str,
Any]`.

---------

Co-authored-by: Dylan Anthony <dbanty@users.noreply.github.com>
Co-authored-by: Dylan Anthony <43723790+dbanty@users.noreply.github.com>

Author: micha91

.changeset/raise_minimum_httpx_version_to_023.md

@@ -0,0 +1,5 @@
+---
+default: major
+---
+
+# Raise minimum httpx version to 0.23

.changeset/removed_ability_to_set_an_array_as_a_multipart_body.md

@@ -0,0 +1,15 @@
+---
+default: major
+---
+
+# Removed ability to set an array as a multipart body
+
+Previously, when defining a request's body as `multipart/form-data`, the generator would attempt to generate code 
+for both `object` schemas and `array` schemas. However, most arrays could not generate valid multipart bodies, as 
+there would be no field names (required to set the `Content-Disposition` headers).
+
+The code to generate any body for `multipart/form-data` where the schema is `array` has been removed, and any such 
+bodies will be skipped. This is not _expected_ to be a breaking change in practice, since the code generated would 
+probably never work.
+
+If you have a use-case for `multipart/form-data` with an `array` schema, please [open a new discussion](https://github.com/openapi-generators/openapi-python-client/discussions) with an example schema and the desired functional Python code.

.changeset/repeat_array_fields_in_multipart_instead_of_serializing_as_json.md

@@ -0,0 +1,12 @@
+---
+default: major
+---
+
+# Change default multipart array serialization
+
+Previously, any arrays of values in a `multipart/form-data` body would be serialized as an `application/json` part.
+This matches the default behavior specified by OpenAPI and supports arrays of files (`binary` format strings).
+However, because this generator doesn't yet support specifying `encoding` per property, this may result in 
+now-incorrect code when the encoding _was_ explicitly set to `application/json` for arrays of scalar values.
+
+PR #938 fixes #692. Thanks @micha91 for the fix, @ratgen and @FabianSchurig for testing, and @davidlizeng for the original report... many years ago 😅.

.github/workflows/checks.yml

@@ -153,12 +153,12 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        httpx_version:
-          - "0.20.0"
-          - ""
+        lockfile:
+          - "pdm.lock"
+          - "pdm.minimal.lock"
     services:
       openapi-test-server:
-        image: ghcr.io/openapi-generators/openapi-test-server:0.0.1
+        image: ghcr.io/openapi-generators/openapi-test-server:0.2.1
         ports:
           - "3000:3000"
     steps:
@@ -170,34 +170,18 @@ jobs:
       - name: Get Python Version
         id: get_python_version
         run: echo "python_version=$(python --version)" >> $GITHUB_OUTPUT
-      - name: Cache dependencies
-        uses: actions/cache@v4
-        with:
-          path: .venv
-          key: ${{ runner.os }}-${{ steps.get_python_version.outputs.python_version }}-dependencies-${{ hashFiles('**/pdm.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-${{ steps.get_python_version.outputs.python_version }}-dependencies
-      - name: Install dependencies
-        run: |
-          pip install pdm
-          python -m venv .venv
-          pdm install
       - name: Cache Generated Client Dependencies
         uses: actions/cache@v4
         with:
           path: integration-tests/.venv
-          key: ${{ runner.os }}-${{ steps.get_python_version.outputs.python_version }}-integration-dependencies-${{ hashFiles('**/pdm.lock') }}
+          key: ${{ runner.os }}-${{ steps.get_python_version.outputs.python_version }}-integration-dependencies-${{ hashFiles('integration-tests/pdm*.lock') }}
           restore-keys: |
             ${{ runner.os }}-${{ steps.get_python_version.outputs.python_version }}-integration-dependencies
-      - name: Set httpx version
-        if: matrix.httpx_version != ''
-        run: |
-          cd integration-tests 
-          pdm add httpx==${{ matrix.httpx_version }}
       - name: Install Integration Dependencies
         run: |
           cd integration-tests
-          pdm install
+          pip install pdm
+          pdm install -L ${{ matrix.lockfile }}
       - name: Run Tests
         run: |
           cd integration-tests

end_to_end_tests/baseline_openapi_3.0.json

@@ -431,51 +431,6 @@
         }
       }
     },
-    "/tests/upload/multiple": {
-      "post": {
-        "tags": [
-          "tests"
-        ],
-        "summary": "Upload multiple files",
-        "description": "Upload several files in the same request",
-        "operationId": "upload_multiple_files_tests_upload_post",
-        "parameters": [],
-        "requestBody": {
-          "content": {
-            "multipart/form-data": {
-              "schema": {
-                "type": "array",
-                "items": {
-                  "type": "string",
-                  "format": "binary"
-                }
-              }
-            }
-          },
-          "required": true
-        },
-        "responses": {
-          "200": {
-            "description": "Successful Response",
-            "content": {
-              "application/json": {
-                "schema": {}
-              }
-            }
-          },
-          "422": {
-            "description": "Validation Error",
-            "content": {
-              "application/json": {
-                "schema": {
-                  "$ref": "#/components/schemas/HTTPValidationError"
-                }
-              }
-            }
-          }
-        }
-      }
-    },
     "/tests/json_body": {
       "post": {
         "tags": [

end_to_end_tests/baseline_openapi_3.1.yaml

@@ -418,51 +418,6 @@ info:
       }
     }
   },
-  "/tests/upload/multiple": {
-    "post": {
-      "tags": [
-        "tests"
-      ],
-      "summary": "Upload multiple files",
-      "description": "Upload several files in the same request",
-      "operationId": "upload_multiple_files_tests_upload_post",
-      "parameters": [ ],
-      "requestBody": {
-        "content": {
-          "multipart/form-data": {
-            "schema": {
-              "type": "array",
-              "items": {
-                "type": "string",
-                "format": "binary"
-              }
-            }
-          }
-        },
-        "required": true
-      },
-      "responses": {
-        "200": {
-          "description": "Successful Response",
-          "content": {
-            "application/json": {
-              "schema": { }
-            }
-          }
-        },
-        "422": {
-          "description": "Validation Error",
-          "content": {
-            "application/json": {
-              "schema": {
-                "$ref": "#/components/schemas/HTTPValidationError"
-              }
-            }
-          }
-        }
-      }
-    }
-  },
   "/tests/json_body": {
     "post": {
       "tags": [

end_to_end_tests/custom-templates-golden-record/my_test_api_client/api/tests/__init__.py

@@ -21,7 +21,6 @@
     token_with_cookie_auth_token_with_cookie_get,
     unsupported_content_tests_unsupported_content_get,
     upload_file_tests_upload_post,
-    upload_multiple_files_tests_upload_post,
 )
 
 
@@ -82,13 +81,6 @@ def upload_file_tests_upload_post(cls) -> types.ModuleType:
         """
         return upload_file_tests_upload_post
 
-    @classmethod
-    def upload_multiple_files_tests_upload_post(cls) -> types.ModuleType:
-        """
-        Upload several files in the same request
-        """
-        return upload_multiple_files_tests_upload_post
-
     @classmethod
     def json_body_tests_json_body_post(cls) -> types.ModuleType:
         """

end_to_end_tests/docstrings-on-attributes-golden-record/my_test_api_client/types.py

@@ -1,8 +1,8 @@
 """Contains some shared types for properties"""
 
-from collections.abc import MutableMapping
+from collections.abc import Mapping, MutableMapping
 from http import HTTPStatus
-from typing import BinaryIO, Generic, Literal, Optional, TypeVar
+from typing import IO, BinaryIO, Generic, Literal, Optional, TypeVar, Union
 
 from attrs import define
 
@@ -14,7 +14,15 @@ def __bool__(self) -> Literal[False]:
 
 UNSET: Unset = Unset()
 
-FileJsonType = tuple[Optional[str], BinaryIO, Optional[str]]
+# The types that `httpx.Client(files=)` can accept, copied from that library.
+FileContent = Union[IO[bytes], bytes, str]
+FileTypes = Union[
+    # (filename, file (or bytes), content_type)
+    tuple[Optional[str], FileContent, Optional[str]],
+    # (filename, file (or bytes), content_type, headers)
+    tuple[Optional[str], FileContent, Optional[str], Mapping[str, str]],
+]
+RequestFiles = list[tuple[str, FileTypes]]
 
 
 @define
@@ -25,7 +33,7 @@ class File:
     file_name: Optional[str] = None
     mime_type: Optional[str] = None
 
-    def to_tuple(self) -> FileJsonType:
+    def to_tuple(self) -> FileTypes:
         """Return a tuple representation that httpx will accept for multipart/form-data"""
         return self.file_name, self.payload, self.mime_type
 
@@ -43,4 +51,4 @@ class Response(Generic[T]):
     parsed: Optional[T]
 
 
-__all__ = ["UNSET", "File", "FileJsonType", "Response", "Unset"]
+__all__ = ["UNSET", "File", "FileTypes", "RequestFiles", "Response", "Unset"]

end_to_end_tests/docstrings-on-attributes-golden-record/pyproject.toml

@@ -12,7 +12,7 @@ include = ["CHANGELOG.md", "my_test_api_client/py.typed"]
 
 [tool.poetry.dependencies]
 python = "^3.9"
-httpx = ">=0.20.0,<0.29.0"
+httpx = ">=0.23.0,<0.29.0"
 attrs = ">=22.2.0"
 python-dateutil = "^2.8.0"
 

end_to_end_tests/golden-record/my_test_api_client/api/bodies/json_like.py

@@ -20,9 +20,8 @@ def _get_kwargs(
         "url": "/bodies/json-like",
     }
 
-    _body = body.to_dict()
+    _kwargs["json"] = body.to_dict()
 
-    _kwargs["json"] = _body
     headers["Content-Type"] = "application/vnd+json"
 
     _kwargs["headers"] = headers