flatpak: Get correct path to QtWebEngine locales

(cherry picked from commit 31e655dd36)

qutebrowser/config/qtargs.py

@@ -189,6 +189,17 @@ def _get_pak_name(locale_name: str) -> str:
     return locale_name.split('-')[0]
 
 
+def _webengine_locales_path() -> pathlib.Path:
+    """Get the path of the QtWebEngine locales."""
+    if version.is_flatpak():
+        # TranslationsPath is /usr/translations on Flatpak, i.e. the path for qtbase,
+        # not QtWebEngine.
+        base = pathlib.Path('/app/translations')
+    else:
+        base = pathlib.Path(QLibraryInfo.location(QLibraryInfo.TranslationsPath))
+    return base / 'qtwebengine_locales'
+
+
 def _get_lang_override(
         webengine_version: utils.VersionNumber,
         locale_name: str
@@ -204,8 +215,7 @@ def _get_lang_override(
     if webengine_version != utils.VersionNumber(5, 15, 3) or not utils.is_linux:
         return None
 
-    locales_path = pathlib.Path(
-        QLibraryInfo.location(QLibraryInfo.TranslationsPath)) / 'qtwebengine_locales'
+    locales_path = _webengine_locales_path()
     if not locales_path.exists():
         log.init.debug(f"{locales_path} not found, skipping workaround!")
         return None

tests/unit/config/test_qtargs_locale_workaround.py

@@ -20,7 +20,7 @@ import os
 import pathlib
 
 import pytest
-from PyQt5.QtCore import QLocale, QLibraryInfo
+from PyQt5.QtCore import QLocale
 
 from qutebrowser.utils import utils
 from qutebrowser.config import qtargs
@@ -414,10 +414,9 @@ def test_lang_workaround_all_locales(lang, expected, qtwe_version):
         locale_name=locale_name,
     )
 
-    locales_path = pathlib.Path(
-        QLibraryInfo.location(QLibraryInfo.TranslationsPath)) / 'qtwebengine_locales'
-
+    locales_path = qtargs._webengine_locales_path()
     original_path = qtargs._get_locale_pak_path(locales_path, locale_name)
+
     if override is None:
         assert original_path.exists()
     else:
@@ -450,8 +449,17 @@ def test_disabled(qtwe_version, config_stub):
 
 @pytest.mark.fake_os('linux')
 def test_no_locales_available(qtwe_version, monkeypatch, caplog):
-    monkeypatch.setattr(qtargs.QLibraryInfo, 'location', lambda _path: '/doesnotexist')
+    path = pathlib.Path('/doesnotexist/qtwebengine_locales')
+    assert not path.exists()
+    monkeypatch.setattr(qtargs, '_webengine_locales_path', lambda: path)
+
     assert qtargs._get_lang_override(qtwe_version, "de-CH") is None
     assert caplog.messages == [
         f"{os.sep}doesnotexist{os.sep}qtwebengine_locales not found, skipping "
         "workaround!"]
+
+
+def test_flatpak_locales_path(monkeypatch):
+    monkeypatch.setenv('FLATPAK_ID', 'org.qutebrowser.qutebrowser')
+    expected = pathlib.Path('/app/translations/qtwebengine_locales')
+    assert qtargs._webengine_locales_path() == expected