Fail on history file parsing errors.

Instead of skipping bad history lines during the import to sql, fail hard. We
don't want to delete the user's old history file if we couldn't parse all of
the lines.

qutebrowser/browser/history.py

@@ -183,12 +183,16 @@ class WebHistory(sql.SqlTable):
         """Import a text file into the sql database."""
         with open(path, 'r', encoding='utf-8') as f:
             rows = []
-            for line in f:
+            for (i, line) in enumerate(f):
+                line = line.strip()
+                if not line:
+                    continue
                 try:
                     row = self._parse_entry(line.strip())
                     rows.append(row)
                 except ValueError:
-                    log.init.warning('Skipping history line {}'.format(line))
+                    raise Exception('Failed to parse line #{} of {}: "{}"'
+                                    .format(i, path, line))
         self.insert_batch(rows)
 
 

tests/unit/browser/webkit/test_history.py

@@ -196,20 +196,16 @@ def test_init(backend, qapp, tmpdir, monkeypatch, cleanup_init):
         assert default_interface is None
 
 
-def test_read(hist, tmpdir, caplog):
+def test_read(hist, tmpdir):
     histfile = tmpdir / 'history'
+    # empty line is deliberate, to test skipping empty lines
     histfile.write('''12345 http://example.com/ title
                       12346 http://qutebrowser.org/
                       67890 http://example.com/path
 
-                      xyz http://example.com/bad-timestamp
-                      12345
-                      http://example.com/no-timestamp
-                      68891-r http://example.com/path/other
-                      68891-r-r http://example.com/double-flag''')
+                      68891-r http://example.com/path/other ''')
 
-    with caplog.at_level(logging.WARNING):
-        hist.read(str(histfile))
+    hist.read(str(histfile))
 
     assert list(hist) == [
         ('http://example.com/', 'title', 12345, False),
@@ -217,3 +213,17 @@ def test_read(hist, tmpdir, caplog):
         ('http://example.com/path', '', 67890, False),
         ('http://example.com/path/other', '', 68891, True)
     ]
+
+
+@pytest.mark.parametrize('line', [
+    'xyz http://example.com/bad-timestamp',
+    '12345',
+    'http://example.com/no-timestamp',
+    '68891-r-r http://example.com/double-flag',
+])
+def test_read_invalid(hist, tmpdir, line):
+    histfile = tmpdir / 'history'
+    histfile.write(line)
+
+    with pytest.raises(Exception):
+        hist.read(str(histfile))