Add optional ICU support for user search (#14464)

Fixes #13655

This change uses ICU (International Components for Unicode) to improve boundary detection in user search.

This change also adds a new dependency on libicu-dev and pkg-config for the Debian packages, which are available in all supported distros.

1 files changed, 25 insertions, 0 deletions

diff --git a/stubs/icu.pyi b/stubs/icu.pyi
new file mode 100644
index 0000000000..efeda7938a
--- /dev/null
+++ b/stubs/icu.pyi
@@ -0,0 +1,25 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Stub for PyICU.
+
+class Locale:
+    @staticmethod
+    def getDefault() -> Locale: ...
+
+class BreakIterator:
+    @staticmethod
+    def createWordInstance(locale: Locale) -> BreakIterator: ...
+    def setText(self, text: str) -> None: ...
+    def nextBoundary(self) -> int: ...