Fix blocking I/O to load netrc when creating requests by bdraco · Pull Request #11634 · aio-libs/aiohttp

bdraco · 2025-10-11T04:31:34Z

What do these changes do?

Fixes blocking I/O in the event loop when netrc authentication is used. Previously, netrc_from_env() was called synchronously in ClientRequest.__init__(), which would block the entire event loop while reading ~/.netrc from disk.

Now netrc lookup happens asynchronously in ClientSession._request() using loop.run_in_executor() before creating the request. Added a quick check for the NETRC environment variable to avoid spawning executor jobs unnecessarily since they're expensive.

Are there changes in behavior for the user?

No user-facing changes. Netrc authentication still works exactly the same way - it just won't block the event loop anymore.

Is it a substantial burden for the maintainers to support this?

no

Related issue number

Fixes #10435

Checklist

I think the code is well written
Unit tests for the changes exist
Documentation reflects the changes
If you provide code modification, please add yourself to CONTRIBUTORS.txt
- The format is <Name> <Surname>.
- Please keep alphabetical order, the file is sorted by names.
Add a new news fragment into the CHANGES/ folder
- name it <issue_or_pr_num>.<type>.rst (e.g. 588.bugfix.rst)
- if you don't have an issue number, change it to the pull request
  number after creating the PR
  - .bugfix: A bug fix for something the maintainers deemed an
    improper undesired behavior that got corrected to match
    pre-agreed expectations.
  - .feature: A new behavior, public APIs. That sort of stuff.
  - .deprecation: A declaration of future API removals and breaking
    changes in behavior.
  - .breaking: When something public is removed in a breaking way.
    Could be deprecated in an earlier release.
  - .doc: Notable updates to the documentation structure or build
    process.
  - .packaging: Notes for downstreams about unobvious side effects
    and tooling. Changes in the test invocation considerations and
    runtime assumptions.
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  - .misc: Changes that are hard to assign to any of the above
    categories.
- Make sure to use full sentences with correct case and punctuation,
  for example:
```
Fixed issue with non-ascii contents in doctest text files
-- by :user:`contributor-gh-handle`.
```
  Use the past tense or the present tense a non-imperative mood,
  referring to what's changed compared to the last released version
  of this project.

Copilot

Pull Request Overview

This PR fixes blocking I/O in the event loop when netrc authentication is used by moving netrc file lookup from synchronous execution in ClientRequest.__init__() to asynchronous execution in ClientSession._request() using loop.run_in_executor().

Moved netrc authentication lookup from ClientRequest.update_auth() to ClientSession._request()
Added environment variable check to avoid unnecessary executor jobs when NETRC is not set
Removed blocking I/O allowances from test configuration

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
aiohttp/client.py	Added async netrc auth lookup in `_request()` method and helper `_get_netrc_auth()`
aiohttp/client_reqrep.py	Removed synchronous netrc auth logic from `update_auth()` method
tests/test_client_session.py	Added comprehensive tests for netrc authentication scenarios
tests/test_client_functional.py	Added functional tests for netrc authentication behavior
tests/test_client_request.py	Removed test that relied on synchronous netrc lookup
tests/conftest.py	Removed blocking I/O allowances and added netrc test fixtures
CHANGES/11634.bugfix.rst	Added changelog entry for the fix
CHANGES/10435.bugfix.rst	Added reference to the main bugfix changelog

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codecov · 2025-10-11T04:50:41Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.74%. Comparing base (d261f8a) to head (ecba61b).
⚠️ Report is 283 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #11634   +/-   ##
=======================================
  Coverage   98.74%   98.74%           
=======================================
  Files         127      127           
  Lines       43467    43529   +62     
  Branches     2327     2327           
=======================================
+ Hits        42922    42984   +62     
  Misses        389      389           
  Partials      156      156

Flag	Coverage Δ
CI-GHA	`98.63% <100.00%> (+<0.01%)`	⬆️
OS-Linux	`98.36% <100.00%> (+<0.01%)`	⬆️
OS-Windows	`96.69% <100.00%> (+<0.01%)`	⬆️
OS-macOS	`97.58% <100.00%> (+<0.01%)`	⬆️
Py-3.10.11	`97.15% <100.00%> (+<0.01%)`	⬆️
Py-3.10.18	`97.65% <100.00%> (+<0.01%)`	⬆️
Py-3.11.13	`97.85% <100.00%> (+<0.01%)`	⬆️
Py-3.11.9	`97.35% <100.00%> (+<0.01%)`	⬆️
Py-3.12.10	`97.45% <100.00%> (+<0.01%)`	⬆️
Py-3.12.11	`97.95% <100.00%> (+<0.01%)`	⬆️
Py-3.13.7	`98.20% <100.00%> (-0.01%)`	⬇️
Py-3.14.0	`98.16% <100.00%> (+<0.01%)`	⬆️
Py-3.14.0t	`97.23% <100.00%> (+<0.01%)`	⬆️
Py-pypy3.10.16-7.3.19	`88.31% <100.00%> (-6.52%)`	⬇️
VM-macos	`97.58% <100.00%> (+<0.01%)`	⬆️
VM-ubuntu	`98.36% <100.00%> (+<0.01%)`	⬆️
VM-windows	`96.69% <100.00%> (+<0.01%)`	⬆️

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Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <[email protected]>

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Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <[email protected]>

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…rc_blockingio_fix

Co-authored-by: Sam Bull <[email protected]>

patchback · 2025-10-15T13:08:09Z

Backport to 3.13: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply cde03b9 on top of patchback/backports/3.13/cde03b98c647272cf12f6e36cce35b5dc252171d/pr-11634

Backporting merged PR #11634 into master

Ensure you have a local repo clone of your fork. Unless you cloned it
from the upstream, this would be your origin remote.
Make sure you have an upstream repo added as a remote too. In these
instructions you'll refer to it by the name upstream. If you don't
have it, here's how you can add it:
```
$ git remote add upstream https://github.com/aio-libs/aiohttp.git
```

Ensure you have the latest copy of upstream and prepare a branch
that will hold the backported code:

$ git fetch upstream
$ git checkout -b patchback/backports/3.13/cde03b98c647272cf12f6e36cce35b5dc252171d/pr-11634 upstream/3.13

Now, cherry-pick PR Fix blocking I/O to load netrc when creating requests #11634 contents into that branch:
```
$ git cherry-pick -x cde03b98c647272cf12f6e36cce35b5dc252171d
```
If it'll yell at you with something like fatal: Commit cde03b98c647272cf12f6e36cce35b5dc252171d is a merge but no -m option was given., add -m 1 as follows instead:
```
$ git cherry-pick -m1 -x cde03b98c647272cf12f6e36cce35b5dc252171d
```
At this point, you'll probably encounter some merge conflicts. You must
resolve them in to preserve the patch from PR Fix blocking I/O to load netrc when creating requests #11634 as close to the
original as possible.

Push this branch to your fork on GitHub:

$ git push origin patchback/backports/3.13/cde03b98c647272cf12f6e36cce35b5dc252171d/pr-11634

Create a PR, ensure that the CI is green. If it's not — update it so that
the tests and any other checks pass. This is it!
Now relax and wait for the maintainers to process your pull request
when they have some cycles to do reviews. Don't worry — they'll tell you if
any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

patchback · 2025-10-15T13:08:17Z

Backport to 3.14: 💔 cherry-picking failed — conflicts found

❌ Failed to cleanly apply cde03b9 on top of patchback/backports/3.14/cde03b98c647272cf12f6e36cce35b5dc252171d/pr-11634

Backporting merged PR #11634 into master

Ensure you have a local repo clone of your fork. Unless you cloned it
from the upstream, this would be your origin remote.
Make sure you have an upstream repo added as a remote too. In these
instructions you'll refer to it by the name upstream. If you don't
have it, here's how you can add it:
```
$ git remote add upstream https://github.com/aio-libs/aiohttp.git
```

Ensure you have the latest copy of upstream and prepare a branch
that will hold the backported code:

$ git fetch upstream
$ git checkout -b patchback/backports/3.14/cde03b98c647272cf12f6e36cce35b5dc252171d/pr-11634 upstream/3.14

Now, cherry-pick PR Fix blocking I/O to load netrc when creating requests #11634 contents into that branch:
```
$ git cherry-pick -x cde03b98c647272cf12f6e36cce35b5dc252171d
```
If it'll yell at you with something like fatal: Commit cde03b98c647272cf12f6e36cce35b5dc252171d is a merge but no -m option was given., add -m 1 as follows instead:
```
$ git cherry-pick -m1 -x cde03b98c647272cf12f6e36cce35b5dc252171d
```
At this point, you'll probably encounter some merge conflicts. You must
resolve them in to preserve the patch from PR Fix blocking I/O to load netrc when creating requests #11634 as close to the
original as possible.

Push this branch to your fork on GitHub:

$ git push origin patchback/backports/3.14/cde03b98c647272cf12f6e36cce35b5dc252171d/pr-11634

Create a PR, ensure that the CI is green. If it's not — update it so that
the tests and any other checks pass. This is it!
Now relax and wait for the maintainers to process your pull request
when they have some cycles to do reviews. Don't worry — they'll tell you if
any improvements are necessary when the time comes!

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

bdraco · 2025-10-16T16:15:59Z

Let me see if I can do the back ports this morning. I've been a bit under water with ESPHome release items

bdraco · 2025-10-16T17:01:51Z

Bit of a hairy conflict

(cherry picked from commit cde03b9)

…n creating requests (#11680)

…n creating requests (#11679)

I optimized this one a bit too much assuming NETRC would always be set in #11634 fixes #11713

Fix blocking I/O to load netrc when creating requests

0b9b763

bdraco added backport-3.13 Trigger automatic backporting to the 3.13 release branch by Patchback robot backport-3.14 Trigger automatic backporting to the 3.14 release branch by Patchback robot labels Oct 11, 2025

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bdraco marked this pull request as ready for review October 11, 2025 05:10

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bdraco and others added 12 commits October 11, 2025 08:08

Update tests/conftest.py

2cca6ed

Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <[email protected]>

Update tests/test_client_session.py

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Update tests/test_client_session.py

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Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <[email protected]>

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Co-authored-by: 🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко) <[email protected]>

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Co-authored-by: Sam Bull <[email protected]>

Merge branch 'master' into netrc_blockingio_fix

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bdraco added a commit that referenced this pull request Oct 16, 2025

Fix blocking I/O to load netrc when creating requests (#11634)

d6aece4

(cherry picked from commit cde03b9)

bdraco added a commit that referenced this pull request Oct 16, 2025

Fix blocking I/O to load netrc when creating requests (#11634)

75f60f9

(cherry picked from commit cde03b9)

bdraco added a commit that referenced this pull request Oct 16, 2025

[PR #11634/cde03b9 backport][3.13] Fix blocking I/O to load netrc whe…

b2ddca1

…n creating requests (#11680)

bdraco added a commit that referenced this pull request Oct 16, 2025

[PR #11634/cde03b9 backport][3.14] Fix blocking I/O to load netrc whe…

46ef156

…n creating requests (#11679)

bdraco mentioned this pull request Oct 24, 2025

The default .netrc file in the home directory is no longer used #11713

Closed

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bdraco added a commit that referenced this pull request Oct 24, 2025

Fix loading netrc when NETRC env var is not set

1e3fb9e

I optimized this one a bit too much assuming NETRC would always be set in #11634 fixes #11713

bdraco mentioned this pull request Oct 24, 2025

Fix loading netrc when NETRC env var is not set #11714

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Detected Blocking Call - Google Generative AI Conversation home-assistant/core#151267

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[PR #11714/0d77d0d6 backport][3.13] Fix loading netrc when NETRC env var is not set #11727

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[PR #11714/0d77d0d6 backport][3.14] Fix loading netrc when NETRC env var is not set #11728

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bdraco commented Oct 11, 2025

What do these changes do?

Are there changes in behavior for the user?

Is it a substantial burden for the maintainers to support this?

Related issue number

Checklist

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Backport to 3.13: 💔 cherry-picking failed — conflicts found

Backporting merged PR #11634 into master

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Backport to 3.14: 💔 cherry-picking failed — conflicts found

Backporting merged PR #11634 into master

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