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Fix [Bug #19632]: Disable external iterator for frozen enumerator (#7791)

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* Fix [Bug #19632]: Disable external iterator for frozen enumerator

Currently, methods to manipulate an external iterator like `#next`
and `#feed` can be called even if a receiver of an enumerator is
frozen. However, these methods change the state of an external
iterator in an enumerator. Therefore, it seems a BUG to me, and
these methods should raise FrozenError if the receiver is frozen.

This fixed the following methods to raise FrozenError if the receiver is
frozen.

- `Enumerator#next`
- `Enumerator#next_values`
- `Enumerator#peek`
- `Enumerator#peek_values`
- `Enumerator#feed`
- `Enumerator#rewind`

* Fix a typo in the document

Thanks @Maumagnaguagno.
This commit is contained in:
Hiroya Fujinami 2023-10-25 16:32:25 +09:00 committed by GitHub
parent a6a67b0524
commit 3e64cf60b5
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 24 additions and 2 deletions
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16
enumerator.c
View File

@ -85,12 +85,16 @@
* puts e.next # => 3
* puts e.next # raises StopIteration
*
* +next+, +next_values+, +peek+ and +peek_values+ are the only methods
* which use external iteration (and Array#zip(Enumerable-not-Array) which uses +next+).
* +next+, +next_values+, +peek+, and +peek_values+ are the only methods
* which use external iteration (and Array#zip(Enumerable-not-Array) which uses +next+ internally).
*
* These methods do not affect other internal enumeration methods,
* unless the underlying iteration method itself has side-effect, e.g. IO#each_line.
*
* FrozenError will be raised if these methods are called against a frozen enumerator.
* Since +rewind+ and +feed+ also change state for external iteration,
* these methods may raise FrozenError too.
*
* External iteration differs *significantly* from internal iteration
* due to using a Fiber:
* - The Fiber adds some overhead compared to internal enumeration.
@ -869,6 +873,8 @@ enumerator_next_values(VALUE obj)
struct enumerator *e = enumerator_ptr(obj);
VALUE vs;
rb_check_frozen(obj);
if (!UNDEF_P(e->lookahead)) {
vs = e->lookahead;
e->lookahead = Qundef;
@ -930,6 +936,8 @@ enumerator_peek_values(VALUE obj)
{
struct enumerator *e = enumerator_ptr(obj);
rb_check_frozen(obj);
if (UNDEF_P(e->lookahead)) {
e->lookahead = get_next_values(obj, e);
}
@ -1054,6 +1062,8 @@ enumerator_feed(VALUE obj, VALUE v)
{
struct enumerator *e = enumerator_ptr(obj);
rb_check_frozen(obj);
if (!UNDEF_P(e->feedvalue)) {
rb_raise(rb_eTypeError, "feed value already set");
}
@ -1076,6 +1086,8 @@ enumerator_rewind(VALUE obj)
{
struct enumerator *e = enumerator_ptr(obj);
rb_check_frozen(obj);
rb_check_funcall(e->obj, id_rewind, 0, 0);
e->fib = 0;

10
test/ruby/test_enumerator.rb
View File

@ -1008,4 +1008,14 @@ class TestEnumerator < Test::Unit::TestCase
Enumerator.product(1..3, foo: 1, bar: 2)
}
end
def test_freeze
e = 3.times.freeze
assert_raise(FrozenError) { e.next }
assert_raise(FrozenError) { e.next_values }
assert_raise(FrozenError) { e.peek }
assert_raise(FrozenError) { e.peek_values }
assert_raise(FrozenError) { e.feed 1 }
assert_raise(FrozenError) { e.rewind }
end
end