Nested models with pydantic 2.0

[szabi]

Describe the bug:

With pydantic 2.0 (using the patched version from #35), I get an error on nested models.

class DisplaySettings(BaseModel):
    multiline: bool
    sort_on: str  # Literal['best_value', 'most_hits']


class InputSettings(BaseModel):
    autocomplete: bool


class OtherSettings(BaseModel):
    ids: list[NonNegativeInt]
    other_ids: list[NonNegativeInt]


class Settings(BaseModel):
    display: DisplaySettings
    input: InputSettings
    ltner: OtherSettings

class User(BaseModel):
    password: SecretStr
    settings: Settings

value = pydantic_form(model=User)

only renders the text_input (for password) visually, and consequently, when pressing "Submit" in the form, will rightly refuse to create a corresponding instance, as there are missing required arguments (settings).

When debugging, the problem happens in ui_rendere.py:117, when getting the _schema_references: I get a warning:

[WARNING] <streamlit.runtime.scriptrunner.script_run_context> Thread 'Thread-73': missing ScriptRunContext

and self._schema_references is set to {}.

This {} is also the reason for the missing input behaviour, as the references cannot be resolved.

See note below for a partial fix!

Expected behaviour:

Nested models working

Steps to reproduce the issue:

See snippet above.

Technical details:

• Host Machine OS (Windows/Linux/Mac): Windows
• Browser (Chrome/Firefox/Safari): Firefox
• Streamlit: 1.24.1
• Pydantic: 2.0.3

Possible Fix:

It seems that the internal schema of the model classes have changed with 2.0

In ui_renderer.py, line 118 and 1171 in the .get changing "definitions" to "$defs" seems to work in the first order:
Next to password also the settings defined in DisplaySettings and InputSettings are rendered.
BUT there is still a problem with the list fields nested in OtherSettings which needs further investigation.

I'm sorry that the PR #35 was not enough to make the lib fully pydantic 2.0 compliant.

As I said, s/"definitions"/"$defs"/ solves some of the problems, but still not all.

[szabi]

Ok, so the issue wrt. nested models not working with pydatnic 2 is resolved by the "suggested fixes".

However, the "list" not working seems to be an orthogonal problem, not related to pydantic 2 (but maybe changes in streamlit, compared to earlier versions):

List-Editing is solved in streamlit-pydantic among others by adding a button: self._render_list_add_button(key, add_col, data_list) (ui_renderer.py:1000), but that tries to add a streamlit.button(...) to the interface. However, adding a regular button within a form is disallowed by (at least current) streamlit button.py:407-411 raising an exception (which is then silently caught and ignored).