Merge pull request #5945 from Textualize/fix-query-wrong-type

Fix query wrong type

Author: willmcgugan

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+
+## [3.7.2] - Unreleased
+
+### Fixed
+
+- Fixed `query_one` and `query_exactly_one` not raising documented `WrongType` exception.
+
 ## [3.7.1] - 2025-07-09
 
 ### Fixed

src/textual/css/query.py

@@ -242,7 +242,7 @@ def first(
             if expect_type is not None:
                 if not isinstance(first, expect_type):
                     raise WrongType(
-                        f"Query value is wrong type; expected {expect_type}, got {type(first)}"
+                        f"Query value is the wrong type; expected type {expect_type.__name__!r}, found {first}"
                     )
             return first
         else:
@@ -324,7 +324,7 @@ def last(
         last = self.nodes[-1]
         if expect_type is not None and not isinstance(last, expect_type):
             raise WrongType(
-                f"Query value is wrong type; expected {expect_type}, got {type(last)}"
+                f"Query value is the wrong type; expected type {expect_type.__name__!r}, found {last}"
             )
         return last
 

src/textual/dom.py

@@ -41,7 +41,7 @@
 from textual.css.errors import DeclarationError, StyleValueError
 from textual.css.match import match
 from textual.css.parse import parse_declarations, parse_selectors
-from textual.css.query import InvalidQueryFormat, NoMatches, TooManyMatches
+from textual.css.query import InvalidQueryFormat, NoMatches, TooManyMatches, WrongType
 from textual.css.styles import RenderStyles, Styles
 from textual.css.tokenize import IDENTIFIER
 from textual.css.tokenizer import TokenError
@@ -65,9 +65,6 @@
     from textual.widget import Widget
     from textual.worker import Worker, WorkType, ResultType
 
-    # Unused & ignored imports are needed for the docs to link to these objects:
-    from textual.css.query import WrongType  # type: ignore  # noqa: F401
-
 from typing_extensions import Literal
 
 _re_identifier = re.compile(IDENTIFIER)
@@ -1488,12 +1485,14 @@ def query_one(
             if not match(selector_set, node):
                 continue
             if expect_type is not None and not isinstance(node, expect_type):
-                continue
+                raise WrongType(
+                    f"Node matching {query_selector!r} is the wrong type; expected type {expect_type.__name__!r}, found {node}"
+                )
             if cache_key is not None:
                 base_node._query_one_cache[cache_key] = node
             return node
 
-        raise NoMatches(f"No nodes match {selector!r} on {self!r}")
+        raise NoMatches(f"No nodes match {selector!r} on {base_node!r}")
 
     if TYPE_CHECKING:
 
@@ -1561,19 +1560,19 @@ def query_exactly_one(
             if not match(selector_set, node):
                 continue
             if expect_type is not None and not isinstance(node, expect_type):
-                continue
+                raise WrongType(
+                    f"Node matching {query_selector!r} is the wrong type; expected type {expect_type.__name__!r}, found {node}"
+                )
             for later_node in iter_children:
                 if match(selector_set, later_node):
-                    if expect_type is not None and not isinstance(node, expect_type):
-                        continue
                     raise TooManyMatches(
                         "Call to query_one resulted in more than one matched node"
                     )
             if cache_key is not None:
                 base_node._query_one_cache[cache_key] = node
             return node
 
-        raise NoMatches(f"No nodes match {selector!r} on {self!r}")
+        raise NoMatches(f"No nodes match {selector!r} on {base_node!r}")
 
     if TYPE_CHECKING:
 

src/textual/getters.py

@@ -176,13 +176,11 @@ def __get__(
         """Get the widget matching the selector and/or type."""
         if obj is None:
             return self
-        child = obj._nodes._get_by_id(self.child_id)
+        child = obj._get_dom_base()._nodes._get_by_id(self.child_id)
         if child is None:
-            raise NoMatches(f"No child found with id={id!r}")
+            raise NoMatches(f"No child found with id={self.child_id!r}")
         if not isinstance(child, self.expect_type):
-            if not isinstance(child, self.expect_type):
-                raise WrongType(
-                    f"Child with id={id!r} is wrong type; expected {self.expect_type}, got"
-                    f" {type(child)}"
-                )
+            raise WrongType(
+                f"Child with id={self.child_id!r} is the wrong type; expected type {self.expect_type.__name__!r}, found {child}"
+            )
         return child

src/textual/widget.py

@@ -998,15 +998,14 @@ def get_child_by_id(
             NoMatches: if no children could be found for this ID
             WrongType: if the wrong type was found.
         """
-        child = self._nodes._get_by_id(id)
+        child = self._get_dom_base()._nodes._get_by_id(id)
         if child is None:
             raise NoMatches(f"No child found with id={id!r}")
         if expect_type is None:
             return child
         if not isinstance(child, expect_type):
             raise WrongType(
-                f"Child with id={id!r} is wrong type; expected {expect_type}, got"
-                f" {type(child)}"
+                f"Child with id={id!r} is the wrong type; expected type {expect_type.__name__!r}, found {child}"
             )
         return child
 
@@ -1042,8 +1041,7 @@ def get_widget_by_id(
         widget = self.query_one(f"#{id}")
         if expect_type is not None and not isinstance(widget, expect_type):
             raise WrongType(
-                f"Descendant with id={id!r} is wrong type; expected {expect_type},"
-                f" got {type(widget)}"
+                f"Descendant with id={id!r} is the wrong type; expected type {expect_type.__name__!r}, found {widget}"
             )
         return widget
 

tests/test_getters.py

@@ -7,7 +7,7 @@
 from textual.widgets import Input, Label
 
 
-async def get_getters() -> None:
+async def test_getters() -> None:
     """Check the getter descriptors work, and return expected errors."""
 
     class QueryApp(App):
@@ -20,8 +20,8 @@ class QueryApp(App):
 
         def compose(self) -> ComposeResult:
             with containers.Vertical():
-                yield Label(id="label1", classes=".red")
-            yield Label(id="label2", classes=".green")
+                yield Label(id="label1", classes="red")
+            yield Label(id="label2", classes="green")
 
     app = QueryApp()
     async with app.run_test():

tests/test_query.py

@@ -364,3 +364,19 @@ def compose(self) -> ComposeResult:
         # Focus non existing
         app.query("#egg").focus()
         assert app.focused.id == "bar"
+
+
+async def test_query_error():
+    class QueryApp(App):
+        def compose(self) -> ComposeResult:
+            yield Input(id="foo")
+
+    app = QueryApp()
+    async with app.run_test():
+        with pytest.raises(WrongType):
+            # Asking for a Label, but the widget is an Input
+            app.query_one("#foo", Label)
+
+        # Widget is an Input so this works
+        foo = app.query_one("#foo", Input)
+        assert isinstance(foo, Input)