GV

GeezerVison

The World Wide Web, restored to 800 pixels of glory.

Home|About|Gaming cabinet|Archives|How it works|Starter sites

On this site

  • Sign in
  • ActionsCI/CD and automation
  • CodespacesCloud development environments
  • All Features
  • Documentation
  • Training
  • Certifications
  • Build with Copilot
  • Customize Copilot
  • Integrations
  • Trending repos
  • GitHub Sponsors
  • Developer articles
  • Enterprises

This view

  • Original page
  • New address

GeezerVison is showing github.com — [3.12] gh-117566: fix IPv6Address.is_loopback for IPv4-mapped loopbacks (GH-117567) by miss-islington · Pull Request #118391 · python/cpython

Conversation

@miss-islington

@miss-islington miss-islington commented Apr 29, 2024 •
edited by bedevere-app Bot
Loading

Uh oh!

There was an error while loading. Please reload this page.

Copy link
Copy Markdown
Contributor

While properties like IPv6Address.is_private account for IPv4-mapped
IPv6 addresses, such as for example:

>>> ipaddress.ip_address("192.168.0.1").is_private
True
>>> ipaddress.ip_address("::ffff:192.168.0.1").is_private
True

...the same doesn't currently apply to the is_loopback property:
>>> ipaddress.ip_address("127.0.0.1").is_loopback
True
>>> ipaddress.ip_address("::ffff:127.0.0.1").is_loopback
False

At minimum, this inconsistency between different properties is
counter-intuitive. Moreover, ::ffff:127.0.0.0/104 is for all intents and
purposes a loopback address, and should be treated as such.
(cherry picked from commit fb7f79b)

Co-authored-by: Faidon Liambotis [email protected]

  • Issue: ipaddress.IPv6Address.is_loopback broken for IPv4-mapped addresses #117566

Sorry, something went wrong.

Uh oh!

There was an error while loading. Please reload this page.

All reactions
@paravoid @miss-islington
pythongh-117566: fix IPv6Address.is_loopback for IPv4-mapped loopbacks (
4ab6c58
pythonGH-117567)

While properties like IPv6Address.is_private account for IPv4-mapped
IPv6 addresses, such as for example:

    >>> ipaddress.ip_address("192.168.0.1").is_private
    True
    >>> ipaddress.ip_address("::ffff:192.168.0.1").is_private
    True
...the same doesn't currently apply to the is_loopback property:
    >>> ipaddress.ip_address("127.0.0.1").is_loopback
    True
    >>> ipaddress.ip_address("::ffff:127.0.0.1").is_loopback
    False

At minimum, this inconsistency between different properties is
counter-intuitive. Moreover, ::ffff:127.0.0.0/104 is for all intents and
purposes a loopback address, and should be treated as such.
(cherry picked from commit fb7f79b)

Co-authored-by: Faidon Liambotis <[email protected]>
This was referenced Apr 29, 2024
ipaddress.IPv6Address.is_loopback broken for IPv4-mapped addresses #117566
Closed
gh-117566: fix IPv6Address.is_loopback for IPv4-mapped loopbacks #117567
Merged
@bedevere-app bedevere-app Bot added the awaiting review label Apr 29, 2024
@encukou
encukou enabled auto-merge (squash) April 29, 2024 14:25
@encukou
encukou merged commit 3989894 into python:3.12 Apr 29, 2024
@bedevere-app bedevere-app Bot removed the awaiting review label Apr 29, 2024
@miss-islington
miss-islington deleted the backport-fb7f79b-3.12 branch January 2, 2026 18:59
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

No reviews

Uh oh!

There was an error while loading. Please reload this page.

Assignees

No one assigned

Labels

None yet

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

Uh oh!

There was an error while loading. Please reload this page.

3 participants

@miss-islington @encukou @paravoid
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
You are visitor 01402503 — GeezerVison does not store the pages you look up.
Best viewed with Netscape Navigator 4.7 or Internet Explorer 6 at 800×600. No cookies required.