feat(checks): add accelerator key consistency check

Add an opt-in quality check that flags strings where the source and translation do not contain a matching accelerator key. It checks both the "&" (Qt/Windows) and "_" (GTK) markers, reporting a problem when the counts differ or the translation contains more than one.

The check is disabled by default and is turned on per string or component with the "accelerators" flag, or skipped with "ignore-accelerators".

Closes #5962

Author: fahadhewad

docs/changes.rst

@@ -5,6 +5,8 @@ Weblate 2026.7
 
 .. rubric:: New features
 
+* Added the :ref:`check-accelerators` quality check, which verifies that accelerator keys are used consistently between the source and the translation. Enable it with the ``accelerators`` flag.
+
 .. rubric:: Improvements
 
 * Management interface access control is now more fine-grained with dedicated site-wide permissions.

docs/snippets/check-flags-autogenerated.rst

@@ -47,6 +47,8 @@
 .. AUTOGENERATED START: check-flags-enables
 .. This section is automatically generated by `./manage.py list_checks`. Do not edit manually.
 
+``accelerators``
+    Enables the :ref:`check-accelerators` quality check.
 ``bbcode-text``
     Treat a text as an Bulletin Board Code (BBCode) document, affects :ref:`check-same`.
     Enables the :ref:`check-bbcode` quality check.
@@ -150,6 +152,8 @@
 .. AUTOGENERATED START: check-flags-ignores
 .. This section is automatically generated by `./manage.py list_checks`. Do not edit manually.
 
+``ignore-accelerators``
+    Skip the :ref:`check-accelerators` quality check.
 ``ignore-bbcode``
     Skip the :ref:`check-bbcode` quality check.
 ``ignore-xml-chars-around-tags``

docs/snippets/checks-autogenerated.rst

@@ -4,6 +4,38 @@ Translation checks
 Executed upon every translation change, helping translators maintain
 good quality translations.
 
+.. AUTOGENERATED START: check-accelerators
+.. This section is automatically generated by `./manage.py list_checks`. Do not edit manually.
+
+.. _check-accelerators:
+
+Accelerator key
+~~~~~~~~~~~~~~~
+
+.. versionadded:: 2026.7
+
+:Summary: Source and translation do not both contain an accelerator key.
+:Scope: translated strings
+:Check class: ``weblate.checks.chars.AcceleratorKeyCheck``
+:Check identifier: ``accelerators``
+:Trigger: This check needs to be enabled using a flag.
+:Flag to enable: ``accelerators``
+:Flag to ignore: ``ignore-accelerators``
+
+.. AUTOGENERATED END: check-accelerators
+
+Accelerator keys (also known as mnemonics) let users trigger a UI action from
+the keyboard. They are marked in the string by a single character, typically
+``&`` (Qt, Windows) or ``_`` (GTK). This check verifies that the source and the
+translation contain the same number of accelerator keys, and that the
+translation does not contain more than one.
+
+.. note::
+
+    A string such as ``Walter & Sons`` might be translated without the
+    ampersand and trigger a false positive. Use the ``ignore-accelerators``
+    flag to skip the check for such strings.
+
 .. AUTOGENERATED START: check-bbcode
 .. This section is automatically generated by `./manage.py list_checks`. Do not edit manually.
 

weblate/checks/chars.py

@@ -41,6 +41,26 @@
 INTERROBANGS = ("?!", "!?", "؟!", "!؟", "？！", "！？", "⁈", "⁉")
 
 
+class AcceleratorKeyCheck(TargetCheck):
+    """Check for inconsistent accelerator keys."""
+
+    check_id = "accelerators"
+    name = gettext_lazy("Accelerator key")
+    description = gettext_lazy(
+        "Source and translation do not both contain an accelerator key."
+    )
+    default_disabled = True
+    version_added = "2026.7"
+
+    def _check_accelerator(self, source: str, target: str, key: str) -> bool:
+        return target.count(key) > 1 or source.count(key) != target.count(key)
+
+    def check_single(self, source: str, target: str, unit: Unit):
+        return self._check_accelerator(source, target, "&") or self._check_accelerator(
+            source, target, "_"
+        )
+
+
 class BeginNewlineCheck(TargetCheck):
     """Check for newlines at beginning."""
 

weblate/checks/defaults.py

@@ -6,6 +6,7 @@
 
 DEFAULT_CHECK_LIST: tuple[str, ...] = (
     "weblate.checks.same.SameCheck",
+    "weblate.checks.chars.AcceleratorKeyCheck",
     "weblate.checks.chars.BeginNewlineCheck",
     "weblate.checks.chars.EndNewlineCheck",
     "weblate.checks.chars.BeginSpaceCheck",

weblate/checks/tests/test_chars_checks.py

@@ -7,6 +7,7 @@
 from django.test import SimpleTestCase
 
 from weblate.checks.chars import (
+    AcceleratorKeyCheck,
     BeginNewlineCheck,
     BeginSpaceCheck,
     DoubleSpaceCheck,
@@ -32,6 +33,34 @@
 from weblate.trans.tests.factories import make_check, make_unit
 
 
+class AcceleratorKeyCheckTest(CheckTestCase):
+    check = AcceleratorKeyCheck()
+
+    def setUp(self) -> None:
+        super().setUp()
+        self.test_good_matching = ("&File", "&File", "accelerators")
+        self.test_good_none = ("File", "File", "accelerators")
+        self.test_good_flag = ("&File", "File", "")
+        self.test_failure_1 = ("&File", "File", "accelerators")
+        self.test_failure_2 = ("File", "&File", "accelerators")
+        self.test_failure_3 = ("&File", "&File &Edit", "accelerators")
+
+    def test_underscore_accelerator(self) -> None:
+        self.do_test(False, ("_File", "_File", "accelerators"))
+        self.do_test(True, ("_File", "File", "accelerators"))
+        self.do_test(True, ("File", "_File", "accelerators"))
+
+    def test_literal_ampersand(self) -> None:
+        # A balanced, literal ampersand is not treated as an accelerator key.
+        self.do_test(False, ("Walter & Sons", "Walter & Sons", "accelerators"))
+
+    def test_multiple_accelerators(self) -> None:
+        # More than one accelerator in the target is reported even if counts match.
+        self.do_test(True, ("&File &Edit", "&File &Edit", "accelerators"))
+        # A mismatched marker type (& vs _) is reported.
+        self.do_test(True, ("&File", "_File", "accelerators"))
+
+
 class BeginNewlineCheckTest(CheckTestCase):
     check = BeginNewlineCheck()
 

weblate/settings_example.py

@@ -728,6 +728,7 @@
 # List of quality checks
 # CHECK_LIST = (
 #     "weblate.checks.same.SameCheck",
+#     "weblate.checks.chars.AcceleratorKeyCheck",
 #     "weblate.checks.chars.BeginNewlineCheck",
 #     "weblate.checks.chars.EndNewlineCheck",
 #     "weblate.checks.chars.BeginSpaceCheck",