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pablogsal merged 10 commits into from
Feb 2, 2021
Merged

bpo-42997: Improve error message for missing : before suites #24292

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8b6576a
bpo-42997: Improve error message for missing : before suites
pablogsal Jan 22, 2021
c35cad6
📜🤖 Added by blurb_it.
blurb-it[bot] Jan 24, 2021
f7ec46d
📜🤖 Added by blurb_it.
blurb-it[bot] Jan 26, 2021
9ff270a
Apply suggestions from code review
pablogsal Jan 28, 2021
e126055
Add the new double '&&' to the grammar syntax highlighter
pablogsal Jan 31, 2021
d5f060b
Clean commented code
pablogsal Feb 1, 2021
c6d6228
Simplify token type handling
pablogsal Feb 1, 2021
78fa16a
Remove comma in the 'one of' error message
pablogsal Feb 1, 2021
efed8af
Check for forced tokens in both runs
pablogsal Feb 1, 2021
231d87a
Simplify how the errors are handled in the grammar
pablogsal Feb 1, 2021
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6 changes: 6 additions & 0 deletions Doc/tools/extensions/peg_highlight.py
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Expand Up @@ -27,6 +27,12 @@ class PEGLexer(RegexLexer):
tokens = {
"ws": [(r"\n", Text), (r"\s+", Text), (r"#.*$", Comment.Singleline),],
"lookaheads": [
# Forced tokens
(r"(&&)(?=\w+\s?)", bygroups(None)),
(r"(&&)(?='.+'\s?)", bygroups(None)),
(r'(&&)(?=".+"\s?)', bygroups(None)),
(r"(&&)(?=\(.+\)\s?)", bygroups(None)),

(r"(?<=\|\s)(&\w+\s?)", bygroups(None)),
(r"(?<=\|\s)(&'.+'\s?)", bygroups(None)),
(r'(?<=\|\s)(&".+"\s?)', bygroups(None)),
Expand Down
38 changes: 22 additions & 16 deletions Grammar/python.gram
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Expand Up @@ -162,22 +162,22 @@ dotted_name[expr_ty]:
| NAME

if_stmt[stmt_ty]:
| 'if' a=named_expression ':' b=block c=elif_stmt {
| 'if' a=named_expression &&':' b=block c=elif_stmt {
_Py_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) }
| 'if' a=named_expression ':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
| 'if' a=named_expression &&':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
elif_stmt[stmt_ty]:
| 'elif' a=named_expression ':' b=block c=elif_stmt {
| 'elif' a=named_expression &&':' b=block c=elif_stmt {
_Py_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) }
| 'elif' a=named_expression ':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
else_block[asdl_stmt_seq*]: 'else' ':' b=block { b }
| 'elif' a=named_expression &&':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
else_block[asdl_stmt_seq*]: 'else' &&':' b=block { b }

while_stmt[stmt_ty]:
| 'while' a=named_expression ':' b=block c=[else_block] { _Py_While(a, b, c, EXTRA) }
| 'while' a=named_expression &&':' b=block c=[else_block] { _Py_While(a, b, c, EXTRA) }

for_stmt[stmt_ty]:
| 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] {
| 'for' t=star_targets 'in' ~ ex=star_expressions &&':' tc=[TYPE_COMMENT] b=block el=[else_block] {
_Py_For(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA) }
| ASYNC 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] {
| ASYNC 'for' t=star_targets 'in' ~ ex=star_expressions &&':' tc=[TYPE_COMMENT] b=block el=[else_block] {
CHECK_VERSION(stmt_ty, 5, "Async for loops are", _Py_AsyncFor(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
| invalid_for_target

Expand All @@ -190,18 +190,20 @@ with_stmt[stmt_ty]:
CHECK_VERSION(stmt_ty, 5, "Async with statements are", _Py_AsyncWith(a, b, NULL, EXTRA)) }
| ASYNC 'with' a[asdl_withitem_seq*]=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
CHECK_VERSION(stmt_ty, 5, "Async with statements are", _Py_AsyncWith(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
| invalid_with_stmt

with_item[withitem_ty]:
| e=expression 'as' t=star_target &(',' | ')' | ':') { _Py_withitem(e, t, p->arena) }
| invalid_with_item
| e=expression { _Py_withitem(e, NULL, p->arena) }

try_stmt[stmt_ty]:
| 'try' ':' b=block f=finally_block { _Py_Try(b, NULL, NULL, f, EXTRA) }
| 'try' ':' b=block ex[asdl_excepthandler_seq*]=except_block+ el=[else_block] f=[finally_block] { _Py_Try(b, ex, el, f, EXTRA) }
| 'try' &&':' b=block f=finally_block { _Py_Try(b, NULL, NULL, f, EXTRA) }
| 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_block+ el=[else_block] f=[finally_block] { _Py_Try(b, ex, el, f, EXTRA) }
except_block[excepthandler_ty]:
| 'except' e=expression t=['as' z=NAME { z }] ':' b=block {
| 'except' e=expression t=['as' z=NAME { z }] &&':' b=block {
_Py_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) }
| 'except' ':' b=block { _Py_ExceptHandler(NULL, NULL, b, EXTRA) }
| 'except' &&':' b=block { _Py_ExceptHandler(NULL, NULL, b, EXTRA) }
finally_block[asdl_stmt_seq*]: 'finally' ':' a=block { a }

return_stmt[stmt_ty]:
Expand All @@ -216,11 +218,11 @@ function_def[stmt_ty]:
| function_def_raw

function_def_raw[stmt_ty]:
| 'def' n=NAME '(' params=[params] ')' a=['->' z=expression { z }] ':' tc=[func_type_comment] b=block {
| 'def' n=NAME '(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block {
_Py_FunctionDef(n->v.Name.id,
(params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)),
b, NULL, a, NEW_TYPE_COMMENT(p, tc), EXTRA) }
| ASYNC 'def' n=NAME '(' params=[params] ')' a=['->' z=expression { z }] ':' tc=[func_type_comment] b=block {
| ASYNC 'def' n=NAME '(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block {
CHECK_VERSION(
stmt_ty,
5,
Expand Down Expand Up @@ -300,7 +302,7 @@ class_def[stmt_ty]:
| a=decorators b=class_def_raw { _PyPegen_class_def_decorators(p, a, b) }
| class_def_raw
class_def_raw[stmt_ty]:
| 'class' a=NAME b=['(' z=[arguments] ')' { z }] ':' c=block {
| 'class' a=NAME b=['(' z=[arguments] ')' { z }] &&':' c=block {
_Py_ClassDef(a->v.Name.id,
(b) ? ((expr_ty) b)->v.Call.args : NULL,
(b) ? ((expr_ty) b)->v.Call.keywords : NULL,
Expand Down Expand Up @@ -718,7 +720,7 @@ invalid_double_type_comments:
| TYPE_COMMENT NEWLINE TYPE_COMMENT NEWLINE INDENT {
RAISE_SYNTAX_ERROR("Cannot have two type comments on def") }
invalid_with_item:
| expression 'as' a=expression {
| expression 'as' a=expression &(',' | ')' | ':') {
RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }

invalid_for_target:
Expand All @@ -731,3 +733,7 @@ invalid_group:
invalid_import_from_targets:
| import_from_as_names ',' {
RAISE_SYNTAX_ERROR("trailing comma not allowed without surrounding parentheses") }

invalid_with_stmt:
| [ASYNC] 'with' ','.(expression ['as' star_target])+ &&':'
| [ASYNC] 'with' '(' ','.(expressions ['as' star_target])+ ','? ')' &&':'
107 changes: 104 additions & 3 deletions Lib/test/test_syntax.py
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Expand Up @@ -229,7 +229,7 @@

>>> with a as b
Traceback (most recent call last):
SyntaxError: invalid syntax
SyntaxError: expected ':'

>>> p = p =
Traceback (most recent call last):
Expand Down Expand Up @@ -331,7 +331,7 @@
>>> class C(x for x in L):
... pass
Traceback (most recent call last):
SyntaxError: invalid syntax
SyntaxError: expected ':'

>>> def g(*args, **kwargs):
... print(args, sorted(kwargs.items()))
Expand Down Expand Up @@ -708,6 +708,107 @@
...
SyntaxError: cannot assign to function call

Missing ':' before suites:

>>> def f()
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> class A
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> if 1
... pass
... elif 1:
... pass
... else:
... x() = 1
Traceback (most recent call last):
SyntaxError: expected ':'

>>> if 1:
... pass
... elif 1
... pass
... else:
... x() = 1
Traceback (most recent call last):
SyntaxError: expected ':'

>>> if 1:
... pass
... elif 1:
... pass
... else
... x() = 1
Traceback (most recent call last):
SyntaxError: expected ':'

>>> for x in range(10)
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> while True
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with blech as something
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with blech
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with blech, block as something
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with blech, block as something, bluch
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with (blech as something)
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with (blech)
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with (blech, block as something)
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> with (blech, block as something, bluch)
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> try
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

>>> try:
... pass
... except
... pass
Traceback (most recent call last):
SyntaxError: expected ':'

Make sure that the old "raise X, Y[, Z]" form is gone:
>>> raise X, Y
Traceback (most recent call last):
Expand Down Expand Up @@ -992,7 +1093,7 @@ def func2():
finally:
pass
"""
self._check_error(code, "invalid syntax")
self._check_error(code, "expected ':'")

def test_invalid_line_continuation_left_recursive(self):
# Check bpo-42218: SyntaxErrors following left-recursive rules
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2021-01-24-20-19-55.bpo-42997.QUOPgP.rst
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@@ -0,0 +1 @@
Improve error message for missing ":" before blocks. Patch by Pablo Galindo.
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