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bpo-2180: Treat line continuation at EOF as a SyntaxError #13401

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Merged
miss-islington merged 3 commits into from
May 18, 2019
Merged

bpo-2180: Treat line continuation at EOF as a SyntaxError #13401

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9437230
Treat line continuation at EOF as a `SyntaxError`
asottile May 18, 2019
e054eaa
Add a file based test to exercise tok_nextc().
gpshead May 18, 2019
657ca9f
Switch to script_helper to fix windows tests
asottile May 18, 2019
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26 changes: 25 additions & 1 deletion Lib/test/test_eof.py
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Original file line number Diff line number Diff line change
@@ -1,7 +1,9 @@
"""test script for a few new invalid token catches"""

import unittest
import sys
from test import support
from test.support import script_helper
import unittest

class EOFTestCase(unittest.TestCase):
def test_EOFC(self):
Expand All @@ -24,5 +26,27 @@ def test_EOFS(self):
else:
raise support.TestFailed

def test_line_continuation_EOF(self):
"""A contination at the end of input must be an error; bpo2180."""
expect = 'unexpected EOF while parsing (<string>, line 1)'
with self.assertRaises(SyntaxError) as excinfo:
exec('x = 5\\')
self.assertEqual(str(excinfo.exception), expect)
with self.assertRaises(SyntaxError) as excinfo:
exec('\\')
self.assertEqual(str(excinfo.exception), expect)

@unittest.skipIf(not sys.executable, "sys.executable required")
def test_line_continuation_EOF_from_file_bpo2180(self):
"""Ensure tok_nextc() does not add too many ending newlines."""
with support.temp_dir() as temp_dir:
file_name = script_helper.make_script(temp_dir, 'foo', '\\')
rc, out, err = script_helper.assert_python_failure(file_name)
self.assertIn(b'unexpected EOF while parsing', err)

file_name = script_helper.make_script(temp_dir, 'foo', 'y = 6\\')
rc, out, err = script_helper.assert_python_failure(file_name)
self.assertIn(b'unexpected EOF while parsing', err)

if __name__ == "__main__":
unittest.main()
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2019-05-17-18-34-30.bpo-2180.aBqHeW.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Treat line continuation at EOF as a ``SyntaxError`` by Anthony Sottile.
11 changes: 10 additions & 1 deletion Parser/tokenizer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -983,7 +983,8 @@ tok_nextc(struct tok_state *tok)
return EOF;
/* Last line does not end in \n,
fake one */
strcpy(tok->inp, "\n");
if (tok->inp[-1] != '\n')
strcpy(tok->inp, "\n");
}
tok->inp = strchr(tok->inp, '\0');
done = tok->inp[-1] == '\n';
Expand Down Expand Up @@ -1674,6 +1675,14 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
tok->cur = tok->inp;
return ERRORTOKEN;
}
c = tok_nextc(tok);
if (c == EOF) {
tok->done = E_EOF;
tok->cur = tok->inp;
return ERRORTOKEN;
} else {
tok_backup(tok, c);
}
tok->cont_line = 1;
goto again; /* Read next line */
}
Expand Down