From 31ac6c79012b0855db50dce18a0848fe85f9ae14 Mon Sep 17 00:00:00 2001
From: LHMQ878 <72402929@cityu-dg.edu.cn>
Date: Tue, 18 Aug 2026 03:08:16 +0800
Subject: [PATCH] fix(memory): match a Latin word embedded in unspaced-script
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InMemoryMemoryService tokenizes an event with \w+, which cannot split a script
that writes without spaces, so 私はPythonでADKを使っています comes back as a
single token. A non-Latin query word is matched as a substring of the event
text, but a Latin one is matched only against whole tokens, so searching that
event for "Python" or "ADK" returned nothing.

An event token that mixes scripts is now also indexed by its ASCII and
non-ASCII runs, which makes the embedded Latin word a token of its own while
still keeping a partial word such as "thon" from matching.

Related: #5501
---
 .../adk/memory/in_memory_memory_service.py    | 22 ++++++++++++++++++-
 .../memory/test_in_memory_memory_service.py   |  7 ++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/google/adk/memory/in_memory_memory_service.py b/src/google/adk/memory/in_memory_memory_service.py
index 94639964c3..d8b31291a6 100644
--- a/src/google/adk/memory/in_memory_memory_service.py
+++ b/src/google/adk/memory/in_memory_memory_service.py
@@ -32,6 +32,7 @@
 
 _UNKNOWN_SESSION_ID = '__unknown_session_id__'
 _MAX_SEARCH_RESULTS = 10
+_SCRIPT_RUN_PATTERN = re.compile(r'[\x00-\x7f]+|[^\x00-\x7f]+')
 
 
 def _user_key(app_name: str, user_id: str) -> tuple[str, str]:
@@ -43,6 +44,25 @@ def _extract_words_lower(text: str) -> set[str]:
   return set(word.lower() for word in re.findall(r'\w+', text))
 
 
+def _extract_searchable_words(text: str) -> set[str]:
+  """Extracts the words an event can be matched on, in lowercase.
+
+  The tokens of _extract_words_lower, plus, for a token that mixes scripts,
+  each of its ASCII and non-ASCII runs. Japanese and Chinese are written
+  without spaces, so 私はPythonを使う is a single \\w+ token and a query for
+  Python matches nothing. Splitting on the boundary between scripts makes the
+  embedded Latin word a token of its own, while still keeping a partial word
+  such as thon from matching.
+
+  Args:
+    text: The text of an event.
+  """
+  words = _extract_words_lower(text)
+  for word in [word for word in words if not word.isascii()]:
+    words.update(_SCRIPT_RUN_PATTERN.findall(word))
+  return words
+
+
 class InMemoryMemoryService(BaseMemoryService):
   """An in-memory memory service for prototyping purpose only.
 
@@ -128,7 +148,7 @@ async def search_memory(
         event_text = ' '.join(
             [part.text for part in event.content.parts if part.text]
         )
-        words_in_event = _extract_words_lower(event_text)
+        words_in_event = _extract_searchable_words(event_text)
         if not words_in_event:
           continue
 
diff --git a/tests/unittests/memory/test_in_memory_memory_service.py b/tests/unittests/memory/test_in_memory_memory_service.py
index 5524226b27..f3473fccaf 100644
--- a/tests/unittests/memory/test_in_memory_memory_service.py
+++ b/tests/unittests/memory/test_in_memory_memory_service.py
@@ -384,8 +384,15 @@ async def test_search_memory_does_not_collide_on_slash_in_identifiers():
         # Mixed: non-Latin substring + Latin token in same event
         ('太郎 works at ABC Corp', '太郎', 1),
         ('太郎 works at ABC Corp', 'ABC', 1),
+        # Latin word inside an unspaced script (no space to tokenize on)
+        ('私はPythonでADKを使っています', 'Python', 1),
+        ('私はPythonでADKを使っています', 'adk', 1),
+        ('我用Python写代码', 'python', 1),
+        ('私はPythonでADKを使っています', '使って', 1),
+        ('私はPythonでADKを使っています', 'Java', 0),
         # Latin partial-word must NOT match (regression guard)
         ('I like to code in Python.', 'thon', 0),
+        ('私はPythonでADKを使っています', 'thon', 0),
     ],
 )
 async def test_search_memory_non_latin(event_text, query, expected_count):