Support IAccessible2 labelled-by relation #17437
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### Link to issue number: Fixes nvaccess#17436 ### Summary of the issue: IAccessible2 has an IA2_RELATION_LABELLED_BY relation type, see https://accessibility.linuxfoundation.org/a11yspecs/ia2/docs/html/group__grp_relations.html#ga7bbace7ffb57476b75d621af2e27d1ff . However, that one was not taken into account by NVDA's "labeledBy" property for objects. This could could be seen for example with LibreOffice that implements handling of that IAccessible2 relation. Additionally, a `None` return value from IAccessibleHandler.accNavigate wasn't handled in `IAccessible._get_labeledBy`, triggering an error, e.g.: >>> focus.labeledBy Traceback (most recent call last): File "<console>", line 1, in <module> File "C:\tools\cygwin\home\user\development\git\nvda\source\baseObject.py", line 59, in __get__ return instance._getPropertyViaCache(self.fget) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\tools\cygwin\home\user\development\git\nvda\source\baseObject.py", line 167, in _getPropertyViaCache val = getterMethod(self) ^^^^^^^^^^^^^^^^^^ File "C:\tools\cygwin\home\user\development\git\nvda\source\NVDAObjects\IAccessible\__init__.py", line 1167, in _get_labeledBy (pacc, accChild) = IAccessibleHandler.accNavigate( ^^^^^^^^^^^^^^^^ TypeError: cannot unpack non-iterable NoneType object ### Description of user facing changes In NVDA's Python console, retrieving the "labeledBy" property now works for objects in applications implementing the "labelled-by" IAccessible2 relation and no longer triggers an error. ### Description of development approach * Extend `IAccessibleHandler.RelationType` with the `LABELLED_BY` relation as defined in the IAccessible2 spec. * Use this relation in `IAccessible._get_labeledBy` before falling back to trying a custom Mozilla/Gecko specific NAVRELATION. * Add handling for the case where `IAccessibleHandler.accNavigate` for the custom Mozilla/Geck approach returns `None` to fix the error triggered otherwise when no relation is set. ### Testing strategy: 1. start NVDA 2. Start LibreOffice Writer 3. open the options dialog: "Tools" -> "Options", go to the "User Data" page 4. move focus to the "Company" text edit 5. open NVDA's Python console (Ctrl+Insert+Z) 6. print the object that the currently focused edit is labelled by, and it's accessible name and role: >>> focus.labeledBy <NVDAObjects.IAccessible.IAccessible object at 0x0BC55A70> >>> focus.labeledBy.name 'Company:' >>> focus.labeledBy.role <Role.STATICTEXT: 7> ### Known issues with pull request: None ### Code Review Checklist: - [x] Documentation: - Change log entry - User Documentation - Developer / Technical Documentation - Context sensitive help for GUI changes - [x] Testing: - Unit tests - System (end to end) tests - Manual testing - [x] UX of all users considered: - Speech - Braille - Low Vision - Different web browsers - Localization in other languages / culture than English - [x] API is compatible with existing add-ons. - [x] Security precautions taken. <!-- Please keep the following --> @coderabbitai summary
seanbudd
reviewed
Nov 27, 2024
Use qualified name.
Otherwise the newly introduced
from __future__ import annotations
in
commit feea4aa
Author: Michael Weghorn <[email protected]>
Date: Wed Nov 27 09:12:38 2024 +0000
Add type annotation
causes
source/NVDAObjects/IAccessible/__init__.py:2391:7: F811 Redefinition of unused `List` from line 13
|
2391 | class List(IAccessible):
| ^^^^ F811
2392 | def _get_role(self):
2393 | return controlTypes.Role.LIST
|
= help: Remove definition: `List`
Found 1 error.
seanbudd
reviewed
Nov 29, 2024
Without deferred evaluation (s. PEPs mentioned
in the newly added comment):
$ ./runlint.bat
Ensuring NVDA Python virtual environment
call ruff check --fix
source\NVDAObjects\IAccessible\__init__.py:1165:30: F821 Undefined name `IAccessible`
|
1163 | return True
1164 |
1165 | def _get_labeledBy(self) -> IAccessible | None:
| ^^^^^^^^^^^ F821
1166 | label = self._getIA2RelationFirstTarget(IAccessibleHandler.RelationType.LABELLED_BY)
1167 | if label:
|
Found 1 error.
Deactivating NVDA Python virtual environment
seanbudd
reviewed
Dec 1, 2024
seanbudd
approved these changes
Dec 1, 2024
seanbudd
reviewed
Dec 1, 2024
See test results for failed build of commit 263c3c810f |
seanbudd
reviewed
Dec 2, 2024
|
Thanks for the review and bringing this in line with the NVDA code conventions, @seanbudd ! |
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Link to issue number:
Fixes #17436
Summary of the issue:
IAccessible2 has an IA2_RELATION_LABELLED_BY relation type, see https://accessibility.linuxfoundation.org/a11yspecs/ia2/docs/html/group__grp_relations.html#ga7bbace7ffb57476b75d621af2e27d1ff . However, that one was not taken into account by NVDA's "labeledBy" property for objects. This could could be seen for example with LibreOffice that implements handling of that IAccessible2 relation.
Additionally, a
Nonereturn value fromIAccessibleHandler.accNavigate wasn't handled
in
IAccessible._get_labeledBy, triggering an error, e.g.:Description of user facing changes
None, unless they're using the Python console or addons making use of the property.
Description of development approach
IAccessibleHandler.RelationTypewith theLABELLED_BYrelation as defined in the IAccessible2 spec.IAccessible._get_labeledBybefore falling back to trying a custom Mozilla/Gecko specific NAVRELATION.IAccessibleHandler.accNavigatefor the custom Mozilla/Geck approach returnsNoneto fix the error triggered otherwise when no relation is set.Testing strategy:
start NVDA
Start LibreOffice Writer
open the options dialog: "Tools" -> "Options", go to the "User Data" page
move focus to the "Company" text edit
open NVDA's Python console (Ctrl+Insert+Z)
print the object that the currently focused edit is labelled by, and it's accessible name and role:
Known issues with pull request:
None
Code Review Checklist:
@coderabbitai summary