fix(parsing): accept subsecond fractions longer than nine digits

src/pendulum/parsing/__init__.py

@@ -49,7 +49,7 @@
     # Subsecond part (optional)
     "    (?P<subsecondsection>"
     "        (?:[.|,])"  # Subsecond separator (optional)
-    r"        (?P<subsecond>\d{1,9})"  # Subsecond
+    r"        (?P<subsecond>\d+)"  # Subsecond (truncated to microseconds later)
     "    )?"
     ")?"
     "$",

src/pendulum/parsing/iso8601.py

@@ -49,7 +49,7 @@
     # Subsecond part (optional)
     "    (?P<subsecondsection>"
     "        (?:[.,])"  # Subsecond separator (optional)
-    r"        (?P<subsecond>\d{1,9})"  # Subsecond
+    r"        (?P<subsecond>\d+)"  # Subsecond (truncated to microseconds later)
     "    )?"
     # Timezone offset
     "    (?P<tz>"

tests/parsing/test_parse_iso8601.py

@@ -82,6 +82,10 @@
             "2016-10-06T12:34:56.123456789+05:30",
             datetime(2016, 10, 6, 12, 34, 56, 123456, FixedTimezone(+19800)),
         ),
+        # More fractional digits than microsecond precision (truncated)
+        ("2016-10-06T12:34:56.123456789012", datetime(2016, 10, 6, 12, 34, 56, 123456)),
+        ("12:34:56.123456789012", time(12, 34, 56, 123456)),
+        ("20161006T123456,123456789012", datetime(2016, 10, 6, 12, 34, 56, 123456)),
         # Week date with time
         ("2008-W39-6T09", datetime(2008, 9, 27, 9, 0, 0, 0)),
     ],

tests/parsing/test_parsing.py

@@ -700,3 +700,19 @@ def test_exif_edge_case():
     assert parsed.hour == 15
     assert parsed.minute == 45
     assert parsed.second == 28
+
+
+def test_subsecond_more_than_nine_digits():
+    # Fractional seconds beyond microsecond precision are truncated (issue #935)
+    text = "2016-10-06T12:34:56.123456789012"
+
+    parsed = parse(text)
+
+    assert parsed.microsecond == 123456
+
+    # The common parser handles the same input
+    text = "2016/10/06 12:34:56.123456789012"
+
+    parsed = parse(text)
+
+    assert parsed.microsecond == 123456