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prevent import statements from assigning to None

This commit is contained in:
Benjamin Peterson 2009-06-13 03:46:30 +00:00
parent 4afbba3d34
commit 565e1b6bb7
3 changed files with 34 additions and 11 deletions
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6
Lib/test/test_compile.py
View File

@ -270,11 +270,17 @@ if 1:
'(a, None) = 0, 0',
'for None in range(10): pass',
'def f(None): pass',
'import None',
'import x as None',
'from x import None',
'from x import y as None'
]
for stmt in stmts:
stmt += "\n"
self.assertRaises(SyntaxError, compile, stmt, 'tmp', 'single')
self.assertRaises(SyntaxError, compile, stmt, 'tmp', 'exec')
# This is ok.
compile("from None import x", "tmp", "exec")
def test_import(self):
succeed = [

2
Misc/NEWS
View File

@ -12,6 +12,8 @@ What's New in Python 2.7 alpha 1
Core and Builtins
-----------------
- Assignment to None using import statements now raises a SyntaxError.
- In the slice AST type, the step field will always be None if a step expression
is not specified.

37
Python/ast.c
View File

@ -2294,7 +2294,7 @@ ast_for_flow_stmt(struct compiling *c, const node *n)
}
static alias_ty
alias_for_import_name(struct compiling *c, const node *n)
alias_for_import_name(struct compiling *c, const node *n, int store)
{
/*
import_as_name: NAME ['as' NAME]
@ -2305,28 +2305,38 @@ alias_for_import_name(struct compiling *c, const node *n)
loop:
switch (TYPE(n)) {
case import_as_name:
case import_as_name: {
node *name_node = CHILD(n, 0);
str = NULL;
if (NCH(n) == 3) {
str = NEW_IDENTIFIER(CHILD(n, 2));
node *str_node = CHILD(n, 2);
if (store && !forbidden_check(c, str_node, STR(str_node)))
return NULL;
str = NEW_IDENTIFIER(str_node);
if (!str)
return NULL;
}
name = NEW_IDENTIFIER(CHILD(n, 0));
if (!forbidden_check(c, name_node, STR(name_node)))
return NULL;
name = NEW_IDENTIFIER(name_node);
if (!name)
return NULL;
return alias(name, str, c->c_arena);
}
case dotted_as_name:
if (NCH(n) == 1) {
n = CHILD(n, 0);
goto loop;
}
else {
alias_ty a = alias_for_import_name(c, CHILD(n, 0));
node *asname_node = CHILD(n, 2);
alias_ty a = alias_for_import_name(c, CHILD(n, 0), store);
if (!a)
return NULL;
assert(!a->asname);
a->asname = NEW_IDENTIFIER(CHILD(n, 2));
if (store && !forbidden_check(c, asname_node, STR(asname_node)))
return NULL;
a->asname = NEW_IDENTIFIER(asname_node);
if (!a->asname)
return NULL;
return a;
@ -2334,7 +2344,10 @@ alias_for_import_name(struct compiling *c, const node *n)
break;
case dotted_name:
if (NCH(n) == 1) {
name = NEW_IDENTIFIER(CHILD(n, 0));
node *name_node = CHILD(n, 0);
if (store && !forbidden_check(c, name_node, STR(name_node)))
return NULL;
name = NEW_IDENTIFIER(name_node);
if (!name)
return NULL;
return alias(name, NULL, c->c_arena);
@ -2408,7 +2421,7 @@ ast_for_import_stmt(struct compiling *c, const node *n)
if (!aliases)
return NULL;
for (i = 0; i < NCH(n); i += 2) {
alias_ty import_alias = alias_for_import_name(c, CHILD(n, i));
alias_ty import_alias = alias_for_import_name(c, CHILD(n, i), 1);
if (!import_alias)
return NULL;
asdl_seq_SET(aliases, i / 2, import_alias);
@ -2425,7 +2438,9 @@ ast_for_import_stmt(struct compiling *c, const node *n)
optional module name */
for (idx = 1; idx < NCH(n); idx++) {
if (TYPE(CHILD(n, idx)) == dotted_name) {
mod = alias_for_import_name(c, CHILD(n, idx));
mod = alias_for_import_name(c, CHILD(n, idx), 0);
if (!mod)
return NULL;
idx++;
break;
} else if (TYPE(CHILD(n, idx)) != DOT) {
@ -2466,14 +2481,14 @@ ast_for_import_stmt(struct compiling *c, const node *n)
/* handle "from ... import *" special b/c there's no children */
if (TYPE(n) == STAR) {
alias_ty import_alias = alias_for_import_name(c, n);
alias_ty import_alias = alias_for_import_name(c, n, 1);
if (!import_alias)
return NULL;
asdl_seq_SET(aliases, 0, import_alias);
}
else {
for (i = 0; i < NCH(n); i += 2) {
alias_ty import_alias = alias_for_import_name(c, CHILD(n, i));
alias_ty import_alias = alias_for_import_name(c, CHILD(n, i), 1);
if (!import_alias)
return NULL;
asdl_seq_SET(aliases, i / 2, import_alias);