Fix placeholder on text inputs (#304)

Author: sergue1

demo/forms.py

@@ -144,6 +144,7 @@ class BigModel(BaseModel):
         None, description='This field is not required, it must start with a capital letter if provided'
     )
     info: Annotated[str | None, Textarea(rows=5)] = Field(None, description='Optional free text information about you.')
+    repo: str = Field(json_schema_extra={'placeholder': '{org}/{repo}'}, title='GitHub repository')
     profile_pic: Annotated[UploadFile, FormFile(accept='image/*', max_size=16_000)] = Field(
         description='Upload a profile picture, must not be more than 16kb'
     )

src/python-fastui/fastui/json_schema.py

@@ -197,6 +197,7 @@ def json_schema_field_to_field(
             initial=schema.get('default'),
             autocomplete=schema.get('autocomplete'),
             description=schema.get('description'),
+            placeholder=schema.get('placeholder'),
         )
 
 

src/python-fastui/tests/test_forms.py

@@ -522,3 +522,28 @@ def test_form_description_leakage():
         'submitUrl': '/foobar/',
         'type': 'ModelForm',
     }
+
+
+class RichForm(BaseModel):
+    repo: str = Field(json_schema_extra={'placeholder': '{org}/{repo}'}, title='GitHub repository')
+
+
+def test_form_fields():
+    m = components.ModelForm(model=RichForm, submit_url='/foobar/')
+
+    assert m.model_dump(by_alias=True, exclude_none=True) == {
+        'formFields': [
+            {
+                'htmlType': 'text',
+                'locked': False,
+                'name': 'repo',
+                'placeholder': '{org}/{repo}',
+                'required': True,
+                'title': ['GitHub repository'],
+                'type': 'FormFieldInput',
+            }
+        ],
+        'method': 'POST',
+        'submitUrl': '/foobar/',
+        'type': 'ModelForm',
+    }