Uncaught IndexError when parsing turtle

[stigbd]

I stumbled upon this when playing around with parsing text to turtle. I did not expect rdflib to throw an IndexError.

Given the following strings:

1. '@prefix ex: <http://example.org/>. ex:Cat ex:hasName "Kitty" .'
2. '@prefix ex: <http://example.org/>. ex:Cat ex:hasName "Kitty" '
3. '@prefix ex: <http://example.org/>. ex:Cat ex:hasName "Kitty"'

Expected behavior:

• parsing (1) does not throw an exception.
• parsing (2) throws rdflib BadSyntax exception.
• parsing (3) throws rdflib BadSyntax exception.

Actual behavior:

• parsing (1) does not throw an exception. ✔️
• parsing (2) throws rdflib BadSyntax exception. ✔️
• parsing (3) throws IndexError. ❌

This is how it was done:

>>> from rdflib import Graph
>>> data = '@prefix ex: <http://example.org/>. ex:Cat ex:hasName "Kitty" .'
>>> graph = Graph().parse(data=data, format="turtle")
>>> data = '@prefix ex: <http://example.org/>. ex:Cat ex:hasName "Kitty" '
>>> graph = Graph().parse(data=data, format="turtle")
Traceback (most recent call last):
  File "<python-input-81>", line 1, in <module>
    graph = Graph().parse(data=data, format="turtle")
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/graph.py", line 1669, in parse
    raise se
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/graph.py", line 1660, in parse
    parser.parse(source, self, **args)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 2034, in parse
    p.loadStream(stream)
    ~~~~~~~~~~~~^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 492, in loadStream
    return self.loadBuf(stream.read())  # Not ideal
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 498, in loadBuf
    self.feed(buf)
    ~~~~~~~~~^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 524, in feed
    i = self.directiveOrStatement(s, j)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 543, in directiveOrStatement
    j = self.statement(argstr, i)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 791, in statement
    j = self.property_list(argstr, i, r[0])
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1153, in property_list
    i = self.objectList(argstr, j, objs)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1209, in objectList
    self.BadSyntax(argstr, j, "EOF found after object")
    ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1743, in BadSyntax
    raise BadSyntax(self._thisDoc, self.lines, argstr, i, msg)
rdflib.plugins.parsers.notation3.BadSyntax: <no detail available>
>>> data = '@prefix ex: <http://example.org/>. ex:Cat ex:hasName "Kitty"'
>>> graph = Graph().parse(data=data, format="turtle")
Traceback (most recent call last):
  File "<python-input-83>", line 1, in <module>
    graph = Graph().parse(data=data, format="turtle")
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/graph.py", line 1660, in parse
    parser.parse(source, self, **args)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 2034, in parse
    p.loadStream(stream)
    ~~~~~~~~~~~~^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 492, in loadStream
    return self.loadBuf(stream.read())  # Not ideal
           ~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 498, in loadBuf
    self.feed(buf)
    ~~~~~~~~~^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 524, in feed
    i = self.directiveOrStatement(s, j)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 543, in directiveOrStatement
    j = self.statement(argstr, i)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 791, in statement
    j = self.property_list(argstr, i, r[0])
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1153, in property_list
    i = self.objectList(argstr, j, objs)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1203, in objectList
    i = self.object(argstr, i, res)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1500, in object
    j = self.subject(argstr, i, res)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 798, in subject
    return self.item(argstr, i, res)
           ~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 890, in item
    return self.path(argstr, i, res)
           ~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 897, in path
    j = self.nodeOrLiteral(argstr, i, res)
  File "/home/stigbd/src/stigbd/hello-sparql/api/.venv/lib/python3.14/site-packages/rdflib/plugins/parsers/notation3.py", line 1573, in nodeOrLiteral
    if argstr[j] == "@":  # Language?
       ~~~~~~^^^
IndexError: string index out of range

python version: 3.14.3
rdflib version: 7.6.0.