fix: Ignore global proxy settings if system thinks there's none

[ShadowRZ]

Content

Ignore global proxy settings from Settings.Global.getString(context.contentResolver, Settings.Global.HTTP_PROXY) if the system says we have no proxy

Motivation and context

Closes #3447

See #3447 (comment) for technical details.

Screenshots / GIFs

Tests

• Step 1: In the provisioned device, Run adb shell settings put global http_proxy :0
• Step 2: Check if Element X Android can select a identity provider without saying We couldn't reach the homeserver

Tested devices

• Physical
• Emulator
• OS version(s): Android 15

Checklist

• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly define what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[CLAassistant]

All committers have signed the CLA.

[github-actions]

Thank you for your contribution! Here are a few things to check in the PR to ensure it's reviewed as quickly as possible:

• Your branch should be based on origin/develop, at least when it was created.
• The title of the PR will be used for release notes, so it needs to describe the change visible to the user.
• The test pass locally running ./gradlew test.
• The code quality check suite pass locally running ./gradlew runQualityChecks.
• If you modified anything related to the UI, including previews, you'll have to run the Record screenshots GH action in your forked repo: that will generate compatible new screenshots. However, given Github Actions limitations, it will prevent the CI from running temporarily, until you upload a new commit after that one. To do so, just pull the latest changes and push an empty commit.

[spaetz]

Bit of context: many applications set http_proxy to :0 in order to disable it. Android libraries understand this, rust however considers :0 to be an invalid entry and connections fail.
This is a frequent source of real world support issues by EXA users. Fixing this would be nice, ideally this is fixed in upstream rust, of course

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 80.12%. Comparing base (34e88f3) to head (02c8c85).
Report is 27 commits behind head on develop.

Files with missing lines	Patch %	Lines
...ibraries/matrix/impl/proxy/DefaultProxyProvider.kt	0.00%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4744      +/-   ##
===========================================
- Coverage    80.13%   80.12%   -0.02%     
===========================================
  Files         2129     2129              
  Lines        56449    56453       +4     
  Branches      7055     7057       +2     
===========================================
- Hits         45236    45233       -3     
- Misses        8795     8799       +4     
- Partials      2418     2421       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[ShadowRZ]

I did some further testing on the emulator:

• adb shell settings put global http_proxy :1: Direct connection
• adb shell settings put global http_proxy :65535: Direct connection
• adb shell settings put global http_proxy 1:65536: Direct connection
• adb shell settings put global http_proxy 1:65535: A proxy defined at 1:65535

So I think that an invalid http_proxy value in Android means no proxy (direct), and to workaround this in the Rust SDK side we can just introduce a "lossy" proxy configration function where it'll throw away invalid proxy configurations.

[jmartinesp]

I gave this a quick try and it seems like your implementation works fine, the defaultProxy value is null if the proxy is not valid.

So I think that an invalid http_proxy value in Android means no proxy (direct), and to workaround this in the Rust SDK side we can just introduce a "lossy" proxy configration function where it'll throw away invalid proxy configurations.

Isn't this what you already did in the PR? Unless I missed some corner case I think we can merge it as is, it's better than the current behaviour.

[bmarty]

Thanks for the update @ShadowRZ , and thanks for the extra test @jmartinesp !