Fix crash on long sql lines

3 files changed, 41 insertions, 12 deletions

diff --git a/qutebrowser/completion/models/histcategory.py b/qutebrowser/completion/models/histcategory.py
index 8b1be213a..175b458fd 100644
--- a/qutebrowser/completion/models/histcategory.py
+++ b/qutebrowser/completion/models/histcategory.py
@@ -22,7 +22,7 @@
 from PyQt5.QtSql import QSqlQueryModel
 
 from qutebrowser.misc import sql
-from qutebrowser.utils import debug
+from qutebrowser.utils import debug, message
 from qutebrowser.config import config
 
 
@@ -88,15 +88,21 @@ class HistoryCategory(QSqlQueryModel):
         if not self._query or len(words) != len(self._query.bound_values()):
             # if the number of words changed, we need to generate a new query
             # otherwise, we can reuse the prepared query for performance
-            self._query = sql.Query(' '.join([
-                "SELECT url, title, {}".format(timefmt),
-                "FROM CompletionHistory",
-                # the incoming pattern will have literal % and _ escaped
-                # we need to tell sql to treat '\' as an escape character
-                'WHERE ({})'.format(where_clause),
-                self._atime_expr(),
-                "ORDER BY last_atime DESC",
-            ]), forward_only=False)
+            try:
+                self._query = sql.Query(' '.join([
+                    "SELECT url, title, {}".format(timefmt),
+                    "FROM CompletionHistory",
+                    # the incoming pattern will have literal % and _ escaped
+                    # we need to tell sql to treat '\' as an escape character
+                    'WHERE ({})'.format(where_clause),
+                    self._atime_expr(),
+                    "ORDER BY last_atime DESC",
+                ]), forward_only=False)
+            except sql.SqlLongQueryError as e:
+                # Sometimes, the query we built up was invalid, for example,
+                # due to a large amount of words.
+                message.error("Error building SQL Query: {}".format(e.text()))
+                return
 
         with debug.log_time('sql', 'Running completion query'):
             self._query.run(**{
diff --git a/qutebrowser/misc/sql.py b/qutebrowser/misc/sql.py
index e3540e082..dd33621f6 100644
--- a/qutebrowser/misc/sql.py
+++ b/qutebrowser/misc/sql.py
@@ -36,6 +36,7 @@ class SqliteErrorCode:
     """
 
     UNKNOWN = '-1'
+    ERROR = '1'  # generic error code
     BUSY = '5'  # database is locked
     READONLY = '8'  # attempt to write a readonly database
     IOERR = '10'  # disk I/O error
@@ -73,6 +74,11 @@ class SqlEnvironmentError(SqlError):
     """
 
 
+class SqlLongQueryError(SqlError):
+
+    """Raised when a query is too long."""
+
+
 class SqlBugError(SqlError):
 
     """Raised on an error interacting with the SQL database.
@@ -112,8 +118,11 @@ def raise_sqlite_error(msg, error):
 
     if error_code in environmental_errors or qtbug_70506:
         raise SqlEnvironmentError(msg, error)
-    else:
-        raise SqlBugError(msg, error)
+    if (error_code == SqliteErrorCode.ERROR and
+            driver_text == "Unable to execute statement" and
+            database_text.startswith("Expression tree is too large")):
+        raise SqlLongQueryError(msg, error)
+    raise SqlBugError(msg, error)
 
 
 def init(db_path):
diff --git a/tests/unit/completion/test_histcategory.py b/tests/unit/completion/test_histcategory.py
index 8fd48f429..7dfda3ea6 100644
--- a/tests/unit/completion/test_histcategory.py
+++ b/tests/unit/completion/test_histcategory.py
@@ -20,11 +20,13 @@
 """Test the web history completion category."""
 
 import datetime
+import logging
 
 import pytest
 
 from qutebrowser.misc import sql
 from qutebrowser.completion.models import histcategory
+from qutebrowser.utils import usertypes
 
 
 @pytest.fixture
@@ -133,6 +135,18 @@ def test_set_pattern_repeated(model_validator, hist):
     ])
 
 
+def test_set_pattern_long(hist, message_mock, caplog):
+    hist.insert({'url': 'example.com/foo', 'title': 'title1', 'last_atime': 1})
+    cat = histcategory.HistoryCategory()
+    with caplog.at_level(logging.ERROR):
+        # pylint: disable=bad-builtin
+        cat.set_pattern(" ".join(map(str, range(10000))))
+        # pylint: enable=bad-builtin
+    msg = message_mock.getmsg(usertypes.MessageLevel.error)
+    assert msg.text.startswith(
+        "Error building SQL Query: Expression tree is too large")
+
+
 @pytest.mark.parametrize('max_items, before, after', [
     (-1, [
         ('a', 'a', '2017-04-16'),