bpo-30529: Fix errors for invalid whitespaces in f-string subexpressions. #1888
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…ons. 'invalid character in identifier' now is raised instead of 'f-string: empty expression not allowed' if a subexpression contains only whitespaces and they are not accepted by Python parser.
serhiy-storchaka
added
needs backport to 3.6
type-bug
Python/ast.c
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| all_whitespace = 0; | ||
| for (s = expr_start; s != expr_end; s++) { | ||
| char c = *s; | ||
| if (!(c == ' ' || c == '\t' || c == '\n' || c == '\014')) { |
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Wouldn't '\014' (formfeed) be better written as '\f'?
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The Python parser uses '\014'. I prefer writing it as '\f' too.
Lib/test/test_fstring.py
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| @@ -279,6 +279,7 @@ def test_missing_expression(self): | |||
| "f'{ !r}'", | |||
| "f'{10:{ }}'", | |||
| "f' { } '", | |||
| "f'''{\t\x0c\r\n}'''", | |||
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\x0c is \f, isn't it? I'd use that, instead.
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Yes. For unknown reasons the repr of '\f' is "'\x0c'".
Lib/test/test_fstring.py
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| @@ -300,6 +301,9 @@ def test_missing_expression(self): | |||
| "f'{:x'", | |||
| ]) | |||
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| self.assertAllRaise(SyntaxError, 'invalid character in identifier', | |||
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Can you add a comment here that says that eval("\xa0") raises SyntaxError with the "invalid character in identifier" text? I think that it's important to know that what you're doing here is trying to match the Python parser. (I realize that, with your change, you're "matching" by actually using the Python parser.)
Or, maybe also add 'eval("\xa0")' to the array to make it obvious that we want the same error raised in both cases?
| for (i = 0; i < len; i++) { | ||
| if (!Py_UNICODE_ISSPACE(PyUnicode_READ(kind, data, i))) { | ||
| all_whitespace = 0; | ||
| for (s = expr_start; s != expr_end; s++) { |
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Can you add a comment here that you're skipping the same whitespace that the Python parser recognizes, and that's why we're specifically not calling Py_UNICODE_ISSPACE? I can see someone (might be me!) and not realizing that Python itself doesn't use Py_UNICODE_ISSPACE and trying to add it back.
…pressions. (pythonGH-1888) 'invalid character in identifier' now is raised instead of 'f-string: empty expression not allowed' if a subexpression contains only whitespaces and they are not accepted by Python parser. (cherry picked from commit 2e9cd58)
'invalid character in identifier' now is raised instead of
'f-string: empty expression not allowed' if a subexpression contains
only whitespaces and they are not accepted by Python parser.