ErrLookup › Textualize/textual

Textualize/textual

The lean application framework for Python. Build sophisticated user interfaces with a simple Python API. Run your apps in the terminal and a web browser. · Python · 238 source files

Analyzed at 06dbeef4bb on 2026-08-27. 151 documented errors.

Code / MessageTypeSeverityTags
App not found in
exception error textual, import, app-discovery, cli
The attribute can't be matched; have you added it to…
exception error textual, decorator, event-handling, selector
Tried to insert a widget with ID
exception error textual, widget, duplicate-id, mount
The message class must have a 'control' to match with the…
exception error textual, decorator, event-handling, selector
Unable to find app in
exception error textual, import, app-discovery, cli
Multiple apps found , try specifying app with "foo.py:app
exception error textual, import, app-discovery, ambiguity
Unable to find in
exception error textual, import, packaging, attribute-error
Unable to parse selector
exception error textual, decorator, css-selector, parse-error
Widget.children is read-only: use Widget.mount(...) or…
exception error textual, widget-tree, read-only, children
No handler for
exception warning python, textual, event-handling, decorator, internal-api
must be one of (received )
validation error textual, css, style-property, enum-validation
Row key is not valid.
exception error data-table, row-key, textual, lookup-failed
Can't encode
exception error python, textual, serialization, type-mismatch, internal-api
is not a valid duration.
validation error python, textual, animation, duration, parse-error
DeclarationError(name, token, message)
validation error textual, css, declaration, stylesheet
module has no attribute
exception error python, attribute-access, lazy-import, module-getattr
Valid rule orientations are
exception error rule, orientation, validation, textual
Expected a character or hatch value here; found
validation error textual, css, hatch, validation
DeclarationError(error.name, error.token, error.message)
validation error textual, css, set-styles, declaration
tree-sitter is available, but no built-in or…
exception warning textarea, tree-sitter, language, missing-dependency, textual
Invalid color value
validation error textual, css, color, type-error
Row index is not valid.
exception error data-table, index-out-of-range, textual, row
Input type must be one of
exception error textual, input, value-error, enum-validation
Multiple handlers for key press
exception error python, textual, keyboard, event-handling, duplicate-handler
invalid percentage value
validation error textual, css, color, percentage-parse
StylesheetErrors(css_rules) (renderable summarizing CSS…
exception error textual, css, stylesheet, parse, renderable
Unable to add due to duplicate ID
exception error optionlist, duplicate-id, textual, widget
Unable to bind data;
exception error textual, reactive, data-binding, tui
must be a str
validation error textual, css, type-error, style-property
Query value is the wrong type; expected type
validation error textual, query, type-mismatch
cannot mix 'none' with other style flags
validation error textual, css, text-style, mutual-exclusion
Value does not match template!
exception error textual, masked-input, value-error, validation
Invalid UTF-8 byte
exception error utf-8, encoding, text-area, textual, validation
No key in COMPONENT_CLASSES
exception error textual, css, component-classes, widget
Select options cannot be empty if selection can't be blank.
exception error select, empty-options, textual, validation
must be a str (e.g. '10%') or a float (e.g. 0.1)
validation error textual, css, fractional, validation
reference to undefined variable
validation error textual, css, variables, undefined-variable
Illegal select value
exception error select, invalid-value, textual, reactive-validator
Missing bytes in
exception error python, textual, serialization, truncated-data, decode-error
unknown word in style flags
validation error textual, css, text-style, enum-validation
pop from empty list
exception error textual, list-view, index-error, empty-collection
New options contain duplicated IDs; Ensure that the IDs are…
exception error textual, option-list, duplicate-id, widget
Template must contain at least one non-separator character
exception error textual, masked-input, value-error, template-validation
Widget is missing attributes; have you called the…
exception critical textual, constructor, super, widget-init
Can't call worker.wait from within the worker function!
exception error worker, deadlock, async, textual
Valid placeholder variants are
exception error placeholder, validation, textual, variant
failed to parse css;
exception error textual, css, stylesheet, parse
More data expected
exception error python, textual, serialization, truncated-data, decode-error
Column key is not valid.
exception error data-table, column-key, textual, lookup-failed
(found ). ; Did you forget a semicolon at the end of a line?
exception error textual, css, tokenizer, syntax
Hatch character must have a cell length of 1
validation error textual, css, hatch, unicode-width
unable to run callback
exception error timer, callback, async, textual
Cannot add an edit to history before it has been performed…
exception error textual, document, history, undo, edit-ordering
No cell exists at .
exception error data-table, coordinate, textual, cell
There is no active worker in this task or thread.
exception error worker, asyncio, context, textual
is an invalid ; identifiers must contain only letters…
validation error textual, dom, identifier, validation, regex
Column index is not valid.
exception error data-table, index-out-of-range, textual, column
Unsupported attempt to run an async worker
exception error worker, async, unsupported-operation, textual
Worker was cancelled, and did not complete.
exception warning worker, cancellation, async, textual
Can't write to the stream after it has stopped.
exception error textual, markdown, runtime-error, stream-closed
The row key already exists.
exception error data-table, duplicate-key, textual, row
Can't animate attribute
exception error python, textual, animation, attribute-access
Don't know how to animate
exception error python, textual, animation, type-mismatch
Call to only_one resulted in more than one matched node
validation error textual, query, too-many-matches
is not a builtin theme, or it has not been registered. To…
exception error textarea, theme, textual, registration
is not a valid scalar
validation error textual, css, scalar, parse, validation
Valid rule line styles are
exception error rule, line-style, validation, textual
expected a callable or string, got
exception error screens, modes, typeerror, textual
No column exists for column_key=
exception error data-table, column-key, textual, lookup-failed
The column key already exists.
exception error data-table, duplicate-key, textual, column
end of file reached
exception error parser, state-machine, eof, tokenize
Unable to parse filter
validation error textual, query, selector, parse-error
Unexpected end of file; did you forget a '}' ? / Unexpected…
exception error textual, css, tokenizer, unexpected-end
Only Selection or a prompt/value tuple is supported in…
exception error selection-list, type-mismatch, textual
value must be a str
exception error textual, digits, type-error, widget
There is no option with an ID of
exception error optionlist, option-not-found, textual
unable to parse in action
exception error actions, parsing, literal-eval, textual
More values provided than there are columns.
exception error data-table, value-error, textual, schema-mismatch
'pane_id' must be a non-empty string or a TabPane with an…
exception error tabbed-content, missing-id, textual
No nodes match on dom
validation error textual, query, no-matches, dom
No screens on stack
exception error screen-stack, textual, state-error
The `call_from_thread` method must run in a different…
exception error threading, asyncio, textual
Unexpected end of file; did you forget a '}' ? / Unexpected…
exception error textual, css, tokenizer, unexpected-end
SyntaxAwareDocument unavailable - tree-sitter is not…
exception critical textual, tree-sitter, optional-dependency, import
Can't clear selection if allow_blank is set to False.
exception error select, allow-blank, textual, clear
Worker must be started before calling this method.
exception error worker, lifecycle, async, textual
Can not create a worker from a non-async function unless…
exception error worker, async, decorator, textual
No row exists for row_key=
exception error data-table, row-key, textual, lookup-failed
Unable to bind non-reactive attribute
exception error textual, reactive, data-binding, dom
Unsupported attempt to run a thread worker
exception error worker, thread, type-error, textual
Expected 2 or 3 values, got
exception error selection-list, tuple-length, textual, validation
Can't await screen.dismiss() from the screen's message…
exception error screen, dismiss, async, deadlock, textual
must be bytes
exception error python, textual, serialization, type-mismatch, internal-api
MODES cannot contain instances, use a type instead
validation error modes, screens, typeerror, textual
Node matching is the wrong type; expected type , found
exception error textual, query, type-mismatch, dom
There is no option with an index of
exception error optionlist, index-out-of-range, textual
No nodes match on
validation error textual, query, no-matches, dom
expected dimensions; found
validation error textual, css, scalar, resolve, units
Request to run a non-async function as an async worker
exception error worker, async, thread, textual
Unable to parse as a query; check for syntax errors
exception error textual, query, selector, syntax