Issue #28739: f-string expressions no longer accepted as docstrings and

by ast.literal_eval() even if they do not include subexpressions.
This commit is contained in:
Serhiy Storchaka 2016-12-11 19:37:19 +02:00
parent 8114f21668
commit 4cc30ae313
4 changed files with 20 additions and 17 deletions

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@ -70,18 +70,18 @@ f'{a * x()}'"""
# Make sure x was called.
self.assertTrue(x.called)
def test_docstring(self):
def f():
f'''Not a docstring'''
self.assertIsNone(f.__doc__)
def g():
'''Not a docstring''' \
f''
self.assertIsNone(g.__doc__)
def test_literal_eval(self):
# With no expressions, an f-string is okay.
self.assertEqual(ast.literal_eval("f'x'"), 'x')
self.assertEqual(ast.literal_eval("f'x' 'y'"), 'xy')
# But this should raise an error.
with self.assertRaisesRegex(ValueError, 'malformed node or string'):
ast.literal_eval("f'x{3}'")
# As should this, which uses a different ast node
with self.assertRaisesRegex(ValueError, 'malformed node or string'):
ast.literal_eval("f'{3}'")
ast.literal_eval("f'x'")
def test_ast_compile_time_concat(self):
x = ['']

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@ -10,6 +10,9 @@ What's New in Python 3.6.1 release candidate 1
Core and Builtins
-----------------
- Issue #28739: f-string expressions no longer accepted as docstrings and
by ast.literal_eval() even if they do not include expressions.
- Issue #28512: Fixed setting the offset attribute of SyntaxError by
PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

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@ -4789,6 +4789,7 @@ ExprList_Finish(ExprList *l, PyArena *arena)
typedef struct {
PyObject *last_str;
ExprList expr_list;
int fmode;
} FstringParser;
#ifdef NDEBUG
@ -4807,6 +4808,7 @@ static void
FstringParser_Init(FstringParser *state)
{
state->last_str = NULL;
state->fmode = 0;
ExprList_Init(&state->expr_list);
FstringParser_check_invariants(state);
}
@ -4869,6 +4871,7 @@ FstringParser_ConcatFstring(FstringParser *state, const char **str,
struct compiling *c, const node *n)
{
FstringParser_check_invariants(state);
state->fmode = 1;
/* Parse the f-string. */
while (1) {
@ -4960,7 +4963,8 @@ FstringParser_Finish(FstringParser *state, struct compiling *c,
/* If we're just a constant string with no expressions, return
that. */
if(state->expr_list.size == 0) {
if (!state->fmode) {
assert(!state->expr_list.size);
if (!state->last_str) {
/* Create a zero length string. */
state->last_str = PyUnicode_FromStringAndSize(NULL, 0);
@ -4984,11 +4988,6 @@ FstringParser_Finish(FstringParser *state, struct compiling *c,
if (!seq)
goto error;
/* If there's only one expression, return it. Otherwise, we need
to join them together. */
if (seq->size == 1)
return seq->elements[0];
return JoinedStr(seq, LINENO(n), n->n_col_offset, c->c_arena);
error:

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@ -3415,7 +3415,8 @@ static int
compiler_joined_str(struct compiler *c, expr_ty e)
{
VISIT_SEQ(c, expr, e->v.JoinedStr.values);
ADDOP_I(c, BUILD_STRING, asdl_seq_LEN(e->v.JoinedStr.values));
if (asdl_seq_LEN(e->v.JoinedStr.values) != 1)
ADDOP_I(c, BUILD_STRING, asdl_seq_LEN(e->v.JoinedStr.values));
return 1;
}