pallets/flask
· — · ★ 0
Analyzed at 6a2f545bfd on 2026-07-31. 66 documented errors.
| Code / Message | Type | Severity | Tags |
|---|---|---|---|
| Working outside of application context. Attempted to use fu | exception | error | flask, python, app-context, runtime-error |
| Working outside of request context. Attempted to use functi | exception | error | flask, python, request-context, runtime-error |
| The session is unavailable because no secret key was set. S | exception | error | flask, python, session, configuration, security |
| The environment variable {variable_name!r} is not set and as | exception | error | flask, python, configuration, environment-variables |
| 'after_this_request' can only be used when a request context | exception | error | flask, python, request-context, hooks |
| 'copy_current_request_context' can only be used when a reque | exception | error | flask, python, request-context, concurrency, decorators |
| There is no request in this context. | exception | error | flask, python, request-context, flask-3 |
| Cannot pop this context ({self!r}), it is not pushed. | exception | error | flask, python, app-context, context-management, testing |
| Cannot pop this context ({self!r}), there is no active conte | exception | error | flask, python, app-context, concurrency, contextvars |
| Cannot pop this context ({self!r}), it is not the active con | exception | error | flask, app-context, request-context, contextvars, lifecycle |
| 'static_folder' must be set to serve static_files. | exception | error | flask, static-files, blueprint, configuration |
| Resources can only be opened for reading. | exception | error | flask, filesystem, resources, instance-folder |
| Install Flask with the 'async' extra in order to use async v | exception | error | flask, async, dependencies, asgiref, installation |
| Unable to build URLs outside an active request without 'SERV | exception | error | flask, url-for, server-name, configuration, background-jobs |
| When specifying '_scheme', '_external' must be True. | exception | error | flask, url-for, scheme, https |
| The view function did not return a valid response tuple. The | exception | error | flask, view-function, response-tuple, return-value |
| The view function for {request.endpoint!r} did not return a | exception | error | flask, view-function, none-return, return-value |
| {e} The view function did not return a valid response. The r | exception | error | flask, view-function, wsgi, force-type, return-value |
| The view function did not return a valid response. The retur | exception | error | flask, view-function, serialization, json, return-value |
| If an instance path is provided it must be absolute. A relat | validation | error | flask, python, configuration, filesystem, app-init |
| The setup method '{f_name}' can no longer be called on the a | exception | error | flask, python, lifecycle, routing, setup |
| Allowed methods must be a list of strings, for example: @app | validation | error | flask, python, routing, type-error, http-methods |
| View function mapping is overwriting an existing endpoint fu | exception | error | flask, python, routing, endpoint, decorators |
| 'name' may not be empty. | validation | error | flask, python, blueprints, validation, app-init |
| 'name' may not contain a dot '.' character. | validation | error | flask, python, blueprints, naming, validation |
| The setup method '{f_name}' can no longer be called on the b | exception | error | flask, python, blueprints, lifecycle, setup |
| Cannot register a blueprint on itself | validation | error | flask, python, blueprints, nesting, validation |
| The name '{self_name}' is already registered for {bp_desc} b | validation | error | flask, python, blueprints, registration, naming |
| 'endpoint' may not contain a dot '.' character. | validation | error | flask, python, blueprints, endpoint, routing, validation |
| 'view_func' name may not contain a dot '.' character. | validation | error | flask, blueprint, routing |
| 'static_folder' must be set to serve static_files. | exception | error | flask, blueprint, static-files |
| Resources can only be opened for reading. | exception | error | flask, blueprint, file-io |
| Use the 'route' decorator to use the 'methods' argument. | validation | error | flask, routing, decorator |
| '{exc_class_or_code}' is not a recognized HTTP error code. U | validation | error | flask, error-handling, http-status |
| {exc_class!r} is an instance, not a class. Handlers can only | validation | error | flask, error-handling, type-error |
| '{exc_class.__name__}' is not a subclass of Exception. Handl | validation | error | flask, error-handling, exceptions |
| 'stream_with_context' can only be used when a request contex | exception | error | flask, request-context, streaming |
| No root path can be found for the provided module {import_na | exception | error | flask, packaging, namespace-package, root-path |
| app.json.response() takes either args or kwargs, not both | exception | error | flask, json, jsonify |
| Object of type {type(o).__name__} is not JSON serializable | exception | error | flask, json, serialization, python |
| Tag '{key}' is already registered. | exception | error | flask, json, session, serialization, python |
| {template} | exception | error | flask, jinja2, templates, python |
| Detected multiple Flask applications in module '{module.__na | exception | error | flask, cli, app-discovery, configuration |
| Detected factory '{attr_name}' in module '{module.__name__}' | exception | error | flask, cli, app-factory, configuration |
| Failed to find Flask application or factory in module '{modu | exception | error | flask, cli, app-discovery, configuration |
| Failed to parse {app_name!r} as an attribute name or functio | exception | error | flask, cli, parsing, configuration |
| Function reference must be a simple name: {app_name!r}. | exception | error | flask, cli, parsing, app-factory |
| Failed to parse arguments as literal values: {app_name!r}. | exception | error | flask, cli, parsing, configuration |
| Failed to find attribute {name!r} in {module.__name__!r}. | exception | error | flask, cli, app-discovery, import |
| The factory {app_name!r} in module {module.__name__!r} could | exception | error | flask, cli, app-factory, configuration |
| A valid Flask application was not obtained from '{module.__n | exception | error | flask, cli, app-discovery, app-factory |
| While importing {module_name!r}, an ImportError was raised: | exception | error | flask, cli, import, dependencies |
| Could not import {module_name!r}. | exception | error | flask, cli, import, app-discovery |
| Could not locate a Flask application. Use the 'flask --app' | exception | error | flask, cli, app-discovery, configuration |
| python-dotenv must be installed to load an env file. | validation | error | flask, cli, dotenv, dependencies |
| Using "--cert" requires Python to be compiled with SSL suppo | validation | error | flask, cli, ssl, https, python-build |
| Using ad-hoc certificates requires the cryptography library. | validation | error | flask, cli, ssl, https, dependencies |
| When "--cert" is "adhoc", "--key" is not used. | validation | error | flask, cli, tls, ssl, dev-server |
| When "--cert" is an SSLContext object, "--key" is not used. | validation | error | flask, cli, tls, ssl-context, dev-server |
| "--cert" must also be specified. | validation | error | flask, cli, tls, configuration |
| Required when using "--cert". | validation | error | flask, cli, tls, configuration |
| Cookies are disabled. Create a client with 'use_cookies=True | exception | error | flask, testing, session, cookies |
| Session backend did not open a session. | exception | error | flask, testing, session, session-interface |
| Cannot nest client invocations | exception | error | flask, testing, context-manager, request-context |
| You tried to access the file {key!r} in the request.files di | exception | error | flask, file-upload, forms, multipart, debug-mode |
| A request was sent to '{request.url}', but routing issued a | exception | error | flask, routing, redirect, trailing-slash, debug-mode, forms |