Merge branch 'dev' into windows-user-friendly-contribute

Author: aGitForEveryone

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 orbs:
   win: circleci/[email protected]
   percy: percy/[email protected]
-  browser-tools: circleci/[email protected].6
+  browser-tools: circleci/[email protected].8
 
 
 jobs:

.pylintrc

@@ -414,7 +414,7 @@ max-bool-expr=5
 max-branches=15
 
 # Maximum number of locals for function / method body
-max-locals=20
+max-locals=25
 
 # Maximum number of parents for a class (see R0901).
 max-parents=7

CHANGELOG.md

@@ -10,8 +10,13 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ## Fixed
 
+- [#2898](https://github.com/plotly/dash/pull/2898) Fix error thrown when using non-existent components in callback running keyword. Fixes [#2897](https://github.com/plotly/dash/issues/2897).
 - [#2892](https://github.com/plotly/dash/pull/2860) Fix ensures dcc.Dropdown menu maxHeight option works with Datatable. Fixes [#2529](https://github.com/plotly/dash/issues/2529) [#2225](https://github.com/plotly/dash/issues/2225)
 - [#2896](https://github.com/plotly/dash/pull/2896) The tabIndex parameter of Div can accept number or string type. Fixes [#2891](https://github.com/plotly/dash/issues/2891)
+- [#2900](https://github.com/plotly/dash/pull/2900) Allow strings in layout list. Fixes [#2890](https://github.com/plotly/dash/issues/2890)
+- [#2908](https://github.com/plotly/dash/pull/2908) Fix when environment variables are ignored by Dash.run() at runtime. Fixes [#2902](https://github.com/plotly/dash/issues/2902)
+- [#2915](https://github.com/plotly/dash/pull/2915) Fix 'AttributeError' when layout is a function that returns a list of components. Fixes [#2905](https://github.com/plotly/dash/issues/2905)
+- [#2956](https://github.com/plotly/dash/pull/2956) Add missing useEffect dependency to dcc.Loading component.
 
 ## [2.17.1] - 2024-06-12
 

MAKE_A_NEW_BACK_END.md

@@ -32,7 +32,7 @@ Each back end must have a way to generate its own wrappers for these React compo
 There is a relatively small set of routes (urls/url patterns) that a Dash server must be prepared to serve. A good way to get a feel for them is to load https://dash.plotly.com/ and look at the page structure (“Elements” tab in Chrome devtools) and the network requests that are made on page load and their responses (“Network” tab). You can see all of the route patterns if you look at the main [`dash.dash` file](https://github.com/plotly/dash/blob/dev/dash/dash.py) and search for `self._add_url` - plus the one `self.server.register_blueprint` call above it. These routes are:
 - `""` and anything not caught by other routes listed below (see https://dash.plotly.com/urls): the “index” route, serving the HTML page skeleton. The Python back end implements a bunch of customization options for this, but for a first version these are unnecessary. See the template given in [`_default_index`](https://github.com/plotly/dash/blob/357f22167d40ef00c92ff165aa6df23c622799f6/dash/dash.py#L58-L74) for the basic structure and pieces that need to be included, most importantly `{%config}` that includes info like whether to display in-browser devtools, and `{%scripts}` and `{%renderer}` that load the necessary `<script>` tags and initialize the dash renderer.
 - `_dash-component-suites/<package_name>/<path>`: serve the JavaScript and related files given by each component package, as described above. Note that we include an extra cache-busting portion in each filename. In the Python version this is the version number and unix timestamp of the file as reported by the filesystem
-- `_dash-layout"`: Gives the JSON structure of the initial Dash components to render on the page (`app.layout` in Python)
+- `_dash-layout`: Gives the JSON structure of the initial Dash components to render on the page (`app.layout` in Python)
 - `_dash-dependencies`: A JSON array of all callback functions defined in the app.
 - `_dash-update-component`: Handles all server-side callbacks. Responds in JSON. Note that `children` outputs can contain Dash components, which must be JSON encoded the same way as in `_dash-layout`.
 - `_reload-hash`: once hot reloading is implemented and enabled (normally only during development), this route tells the page when something has changed on the server and the page should refresh.

components/dash-core-components/src/components/Loading.react.js

@@ -122,7 +122,7 @@ const Loading = ({
                 }
             }
         }
-    }, [delay_hide, delay_show, loading_state, display]);
+    }, [delay_hide, delay_show, loading_state, display, showSpinner]);
 
     const Spinner = showSpinner && getSpinner(spinnerType);
 

dash/_callback.py

@@ -1,6 +1,7 @@
 import collections
 import hashlib
 from functools import wraps
+from typing import Callable, Optional, Any
 
 import flask
 
@@ -67,6 +68,7 @@ def callback(
     cancel=None,
     manager=None,
     cache_args_to_ignore=None,
+    on_error: Optional[Callable[[Exception], Any]] = None,
     **_kwargs,
 ):
     """
@@ -137,6 +139,10 @@ def callback(
             this should be a list of argument indices as integers.
         :param interval:
             Time to wait between the long callback update requests.
+        :param on_error:
+            Function to call when the callback raises an exception. Receives the
+            exception object as first argument. The callback_context can be used
+            to access the original callback inputs, states and output.
     """
 
     long_spec = None
@@ -186,6 +192,7 @@ def callback(
         long=long_spec,
         manager=manager,
         running=running,
+        on_error=on_error,
     )
 
 
@@ -226,7 +233,7 @@ def insert_callback(
     long=None,
     manager=None,
     running=None,
-    dynamic_creator=False,
+    dynamic_creator: Optional[bool] = False,
     no_output=False,
 ):
     if prevent_initial_call is None:
@@ -272,8 +279,16 @@ def insert_callback(
     return callback_id
 
 
-# pylint: disable=R0912, R0915
-def register_callback(  # pylint: disable=R0914
+def _set_side_update(ctx, response) -> bool:
+    side_update = dict(ctx.updated_props)
+    if len(side_update) > 0:
+        response["sideUpdate"] = side_update
+        return True
+    return False
+
+
+# pylint: disable=too-many-branches,too-many-statements
+def register_callback(
     callback_list, callback_map, config_prevent_initial_callbacks, *_args, **_kwargs
 ):
     (
@@ -297,6 +312,7 @@ def register_callback(  # pylint: disable=R0914
     long = _kwargs.get("long")
     manager = _kwargs.get("manager")
     running = _kwargs.get("running")
+    on_error = _kwargs.get("on_error")
     if running is not None:
         if not isinstance(running[0], (list, tuple)):
             running = [running]
@@ -342,6 +358,8 @@ def add_context(*args, **kwargs):
                 "callback_context", AttributeDict({"updated_props": {}})
             )
             callback_manager = long and long.get("manager", app_callback_manager)
+            error_handler = on_error or kwargs.pop("app_on_error", None)
+
             if has_output:
                 _validate.validate_output_spec(insert_output, output_spec, Output)
 
@@ -351,7 +369,7 @@ def add_context(*args, **kwargs):
                 args, inputs_state_indices
             )
 
-            response = {"multi": True}
+            response: dict = {"multi": True}
             has_update = False
 
             if long is not None:
@@ -440,10 +458,24 @@ def add_context(*args, **kwargs):
                     isinstance(output_value, dict)
                     and "long_callback_error" in output_value
                 ):
-                    error = output_value.get("long_callback_error")
-                    raise LongCallbackError(
+                    error = output_value.get("long_callback_error", {})
+                    exc = LongCallbackError(
                         f"An error occurred inside a long callback: {error['msg']}\n{error['tb']}"
                     )
+                    if error_handler:
+                        output_value = error_handler(exc)
+
+                        if output_value is None:
+                            output_value = NoUpdate()
+                        # set_props from the error handler uses the original ctx
+                        # instead of manager.get_updated_props since it runs in the
+                        # request process.
+                        has_update = (
+                            _set_side_update(callback_ctx, response)
+                            or output_value is not None
+                        )
+                    else:
+                        raise exc
 
                 if job_running and output_value is not callback_manager.UNDEFINED:
                     # cached results.
@@ -462,10 +494,22 @@ def add_context(*args, **kwargs):
                 if output_value is callback_manager.UNDEFINED:
                     return to_json(response)
             else:
-                output_value = _invoke_callback(func, *func_args, **func_kwargs)
-
-            if NoUpdate.is_no_update(output_value):
-                raise PreventUpdate
+                try:
+                    output_value = _invoke_callback(func, *func_args, **func_kwargs)
+                except PreventUpdate as err:
+                    raise err
+                except Exception as err:  # pylint: disable=broad-exception-caught
+                    if error_handler:
+                        output_value = error_handler(err)
+
+                        # If the error returns nothing, automatically puts NoUpdate for response.
+                        if output_value is None:
+                            if not multi:
+                                output_value = NoUpdate()
+                            else:
+                                output_value = [NoUpdate for _ in output_spec]
+                    else:
+                        raise err
 
             component_ids = collections.defaultdict(dict)
 
@@ -487,12 +531,12 @@ def add_context(*args, **kwargs):
                 )
 
                 for val, spec in zip(flat_output_values, output_spec):
-                    if isinstance(val, NoUpdate):
+                    if NoUpdate.is_no_update(val):
                         continue
                     for vali, speci in (
                         zip(val, spec) if isinstance(spec, list) else [[val, spec]]
                     ):
-                        if not isinstance(vali, NoUpdate):
+                        if not NoUpdate.is_no_update(vali):
                             has_update = True
                             id_str = stringify_id(speci["id"])
                             prop = clean_property_name(speci["property"])
@@ -506,10 +550,7 @@ def add_context(*args, **kwargs):
                 flat_output_values = []
 
             if not long:
-                side_update = dict(callback_ctx.updated_props)
-                if len(side_update) > 0:
-                    has_update = True
-                    response["sideUpdate"] = side_update
+                has_update = _set_side_update(callback_ctx, response) or has_update
 
             if not has_update:
                 raise PreventUpdate

dash/_validate.py

@@ -439,11 +439,13 @@ def _validate_id(comp):
 
     if isinstance(layout_value, (list, tuple)):
         for component in layout_value:
+            if isinstance(component, (str,)):
+                continue
             if isinstance(component, (Component,)):
                 _validate(component)
             else:
                 raise exceptions.NoLayoutException(
-                    "List of components as layout must be a list of components only."
+                    "Only strings and components are allowed in a list layout."
                 )
     else:
         _validate(layout_value)

dash/dash-renderer/src/actions/callbacks.ts

@@ -36,7 +36,7 @@ import {
 } from '../types/callbacks';
 import {isMultiValued, stringifyId, isMultiOutputProp} from './dependencies';
 import {urlBase} from './utils';
-import {getCSRFHeader} from '.';
+import {getCSRFHeader, dispatchError} from '.';
 import {createAction, Action} from 'redux-actions';
 import {addHttpHeaders} from '../actions';
 import {notifyObservers, updateProps} from './index';
@@ -330,10 +330,29 @@ async function handleClientside(
     return result;
 }
 
-function updateComponent(component_id: any, props: any) {
+function updateComponent(component_id: any, props: any, cb: ICallbackPayload) {
     return function (dispatch: any, getState: any) {
-        const paths = getState().paths;
+        const {paths, config} = getState();
         const componentPath = getPath(paths, component_id);
+        if (!componentPath) {
+            if (!config.suppress_callback_exceptions) {
+                dispatchError(dispatch)(
+                    'ID running component not found in layout',
+                    [
+                        'Component defined in running keyword not found in layout.',
+                        `Component id: "${stringifyId(component_id)}"`,
+                        'This ID was used in the callback(s) for Output(s):',
+                        `${cb.output}`,
+                        'You can suppress this exception by setting',
+                        '`suppress_callback_exceptions=True`.'
+                    ]
+                );
+            }
+            // We need to stop further processing because functions further on
+            // can't operate on an 'undefined' object, and they will throw an
+            // error.
+            return;
+        }
         dispatch(
             updateProps({
                 props,
@@ -381,7 +400,7 @@ function sideUpdate(outputs: SideUpdateOutput, cb: ICallbackPayload) {
                 return acc;
             }, [] as any[])
             .forEach(([id, idProps]) => {
-                dispatch(updateComponent(id, idProps));
+                dispatch(updateComponent(id, idProps, cb));
             });
     };
 }

dash/dash.py

@@ -16,7 +16,7 @@
 import base64
 import traceback
 from urllib.parse import urlparse
-from typing import Dict, Optional, Union
+from typing import Any, Callable, Dict, Optional, Union
 
 import flask
 
@@ -369,6 +369,10 @@ class Dash:
 
     :param description:  Sets a default description for meta tags on Dash pages (use_pages=True).
 
+    :param on_error: Global callback error handler to call when
+        an exception is raised. Receives the exception object as first argument.
+        The callback_context can be used to access the original callback inputs,
+        states and output.
     """
 
     _plotlyjs_url: str
@@ -409,6 +413,7 @@ def __init__(  # pylint: disable=too-many-statements
         hooks: Union[RendererHooks, None] = None,
         routing_callback_inputs: Optional[Dict[str, Union[Input, State]]] = None,
         description=None,
+        on_error: Optional[Callable[[Exception], Any]] = None,
         **obsolete,
     ):
         _validate.check_obsolete(obsolete)
@@ -520,6 +525,7 @@ def __init__(  # pylint: disable=too-many-statements
         self._layout = None
         self._layout_is_function = False
         self.validation_layout = None
+        self._on_error = on_error
         self._extra_components = []
 
         self._setup_dev_tools()
@@ -708,31 +714,9 @@ def layout(self, value):
             and not self.config.suppress_callback_exceptions
         ):
 
-            def simple_clone(c, children=None):
-                cls = type(c)
-                # in Py3 we can use the __init__ signature to reduce to just
-                # required args and id; in Py2 this doesn't work so we just
-                # empty out children.
-                sig = getattr(cls.__init__, "__signature__", None)
-                props = {
-                    p: getattr(c, p)
-                    for p in c._prop_names  # pylint: disable=protected-access
-                    if hasattr(c, p)
-                    and (
-                        p == "id" or not sig or sig.parameters[p].default == c.REQUIRED
-                    )
-                }
-                if props.get("children", children):
-                    props["children"] = children or []
-                return cls(**props)
-
             layout_value = self._layout_value()
             _validate.validate_layout(value, layout_value)
-            self.validation_layout = simple_clone(
-                # pylint: disable=protected-access
-                layout_value,
-                [simple_clone(c) for c in layout_value._traverse_ids()],
-            )
+            self.validation_layout = layout_value
 
     @property
     def index_string(self):
@@ -1377,6 +1361,7 @@ def dispatch(self):
                     outputs_list=outputs_list,
                     long_callback_manager=self._background_manager,
                     callback_context=g,
+                    app_on_error=self._on_error,
                 )
             )
         )
@@ -1981,9 +1966,9 @@ def delete_resource(resources):
 
     def run(
         self,
-        host=os.getenv("HOST", "127.0.0.1"),
-        port=os.getenv("PORT", "8050"),
-        proxy=os.getenv("DASH_PROXY", None),
+        host="127.0.0.1",
+        port="8050",
+        proxy=None,
         debug=None,
         jupyter_mode: JupyterDisplayMode = None,
         jupyter_width="100%",
@@ -2109,6 +2094,12 @@ def run(
             dev_tools_prune_errors,
         )
 
+        # Evaluate the env variables at runtime
+
+        host = os.getenv("HOST", host)
+        port = os.getenv("PORT", port)
+        proxy = os.getenv("DASH_PROXY", proxy)
+
         # Verify port value
         try:
             port = int(port)