Add Arc::new_cyclic #75505

Dylan-DPC-zz · 2020-08-13T22:50:55Z

Rework of #72443

References #75861

pickfire · 2020-08-14T02:38:34Z

library/alloc/src/sync.rs

+  /// # Examples
+  /// ```
+  /// #![feature(arc_new_cyclic)]
+  /// #![allow(dead_code)]


Suggested change

/// #![allow(dead_code)]

/// # #![allow(dead_code)]

pickfire · 2020-08-14T02:39:16Z

library/alloc/src/sync.rs

@@ -328,6 +328,79 @@ impl<T> Arc<T> {
        Self::from_inner(Box::leak(x).into())
    }

+    /// Constructs a new `Arc<T>` using a weak reference to itself. Attempting
+  /// to upgrade the weak reference before this function returns will result


I think the indentation for docs is off starting here.

That's odd, is this not just cherry-picking the commits of #72443?

cherry picking took a while due to some conflicts since this pr was small, I pasted the contents directly into respectively files. I ran tidy again now which would have fixed this issues

pickfire · 2020-08-14T02:40:23Z

library/alloc/src/sync.rs

+  /// let foo = Arc::new_cyclic(|me| Foo {
+  ///     me: me.clone(),
+  /// });
+  /// ```


What is the use case for this example? I don't understand by just looking at the example, maybe we should provide a more realistic use case?

library/alloc/src/sync.rs

pickfire · 2020-08-14T02:43:35Z

library/alloc/src/sync.rs

@@ -1608,8 +1682,11 @@ impl<T: ?Sized> Weak<T> {
                abort();
            }

-            // Relaxed is valid for the same reason it is on Arc's Clone impl
-            match inner.strong.compare_exchange_weak(n, n + 1, Relaxed, Relaxed) {
+            // Relaxed is fine for the failure case because we don't have any expectations about the new state.


Isn't this comment too long?

I find it helpful so +1

RalfJung

As noted before, a similar API should be added to Rc.

KodrAus · 2020-08-24T00:06:47Z

library/alloc/src/sync.rs

+    /// });
+    /// ```
+    #[inline]
+    #[unstable(feature = "arc_new_cyclic", issue = "none")]


Suggested change

#[unstable(feature = "arc_new_cyclic", issue = "none")]

#[unstable(feature = "arc_new_cyclic", issue = "75861")]

KodrAus · 2020-08-24T00:07:49Z

I've opened up #75861 as a tracking issue with a note about adding a similar API for Rc.

r=me with the current suggested edits added.

Dylan-DPC-zz · 2020-08-24T00:39:15Z

@bors r=KodrAus

bors · 2020-08-24T00:39:17Z

📌 Commit c26a8d5 has been approved by KodrAus

bors · 2020-08-24T01:57:31Z

⌛ Testing commit c26a8d5 with merge 9288641c15b77a6a4651e2d4ca5a6583d0e19d92...

rust-log-analyzer · 2020-08-24T02:10:54Z

The job mingw-check of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

+ /scripts/validate-toolstate.sh
Cloning into 'rust-toolstate'...
<Nothing changed>
Traceback (most recent call last):
  File "../../src/tools/publish_toolstate.py", line 283, in <module>
    validate_maintainers(repo, github_token)
  File "../../src/tools/publish_toolstate.py", line 84, in validate_maintainers
    'Accept': 'application/vnd.github.hellcat-preview+json',
  File "/usr/lib/python3.6/urllib/request.py", line 223, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.6/urllib/request.py", line 532, in open
    response = meth(req, response)
  File "/usr/lib/python3.6/urllib/request.py", line 642, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python3.6/urllib/request.py", line 570, in error
    return self._call_chain(*args)
  File "/usr/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.6/urllib/request.py", line 650, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden
  local time: Mon Aug 24 02:10:43 UTC 2020
  network time: Mon, 24 Aug 2020 02:10:44 GMT
== end clock drift check ==
== end clock drift check ==
##[error]Process completed with exit code 1.
Terminate orphan process: pid (6067) (node)
Terminate orphan process: pid (6094) (python)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @rust-lang/infra. (Feature Requests)

bors · 2020-08-24T02:12:14Z

💔 Test failed - checks-actions

RalfJung · 2020-08-24T06:41:03Z

Not sure what this is:

+ /scripts/validate-toolstate.sh
Cloning into 'rust-toolstate'...
<Nothing changed>
Traceback (most recent call last):
  File "../../src/tools/publish_toolstate.py", line 283, in <module>
    validate_maintainers(repo, github_token)
  File "../../src/tools/publish_toolstate.py", line 84, in validate_maintainers
    'Accept': 'application/vnd.github.hellcat-preview+json',
  File "/usr/lib/python3.6/urllib/request.py", line 223, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/lib/python3.6/urllib/request.py", line 532, in open
    response = meth(req, response)
  File "/usr/lib/python3.6/urllib/request.py", line 642, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python3.6/urllib/request.py", line 570, in error
    return self._call_chain(*args)
  File "/usr/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.6/urllib/request.py", line 650, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden

But let's hope it's a spurious network issue.

@bors retry

bors · 2020-08-24T08:27:04Z

⌛ Testing commit c26a8d5 with merge 9d74562...

bors · 2020-08-24T10:29:21Z

☀️ Test successful - checks-actions, checks-azure
Approved by: KodrAus
Pushing 9d74562 to master...

Add Arc::new_cyclic

76b99d5

rust-highfive assigned KodrAus Aug 13, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Aug 13, 2020

Dylan-DPC added 2 commits August 14, 2020 01:05

fix duplicated feature gate

db34e35

add missing newline

fdc2d1f

pickfire reviewed Aug 14, 2020

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pickfire reviewed Aug 14, 2020

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RalfJung mentioned this pull request Aug 14, 2020

Add Arc::new_with() function for constructing self-referential data structures #72443

Closed

RalfJung reviewed Aug 14, 2020

View reviewed changes

tidy up

9ad17b9

Dylan-DPC-zz added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 20, 2020

KodrAus mentioned this pull request Aug 24, 2020

Tracking Issue for arc_new_cyclic #75861

Closed

4 tasks

KodrAus reviewed Aug 24, 2020

View reviewed changes

add issue number

c26a8d5

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 24, 2020

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Aug 24, 2020

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 24, 2020

bors added the merged-by-bors This PR was explicitly merged by bors. label Aug 24, 2020

bors merged commit 9d74562 into rust-lang:master Aug 24, 2020

bors mentioned this pull request Aug 24, 2020

specialize some collection and iterator operations to run in-place #70793

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cuviper added this to the 1.47.0 milestone May 2, 2024

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Add Arc::new_cyclic #75505

Add Arc::new_cyclic #75505

Dylan-DPC-zz commented Aug 13, 2020 •

edited

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RalfJung commented Aug 24, 2020

bors commented Aug 24, 2020

bors commented Aug 24, 2020

	#[unstable(feature = "arc_new_cyclic", issue = "none")]
	#[unstable(feature = "arc_new_cyclic", issue = "75861")]

Add Arc::new_cyclic #75505

Add Arc::new_cyclic #75505

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Dylan-DPC-zz commented Aug 13, 2020 • edited Loading

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KodrAus commented Aug 24, 2020

Dylan-DPC-zz commented Aug 24, 2020

bors commented Aug 24, 2020

bors commented Aug 24, 2020

rust-log-analyzer commented Aug 24, 2020

bors commented Aug 24, 2020

RalfJung commented Aug 24, 2020

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bors commented Aug 24, 2020

Dylan-DPC-zz commented Aug 13, 2020 •

edited

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