Fix misleading WSLInterop browser login errors

[Copilot]

Related command

az login

Description

On newer WSL environments, interop can be enabled through entries such as WSLInterop-late, while older browser-launch fallbacks still probe /proc/sys/fs/binfmt_misc/WSLInterop and emit misleading “WSL Interoperability is disabled” errors. az login can still succeed, but the error output incorrectly suggests WSL is misconfigured.

• WSL interop detection

  • Detects enabled WSLInterop* binfmt entries, including WSLInterop-late.
  • Falls back to WSL_INTEROP when binfmt metadata is unavailable.

• Interactive login browser launch

  • Routes MSAL browser opening through Azure CLI’s WSL-aware launcher when interop is enabled.
  • Avoids noisy WSL fallback output by launching through PowerShell with stderr/stdout suppressed.
  • Passes the login URL via subprocess environment rather than command interpolation.

• Safety and concurrency

  • Validates browser URLs as HTTP(S) with a host and no control characters.
  • Serializes temporary webbrowser.open patching during interactive login.

Testing Guide

Focused regression coverage was added for:

• WSLInterop-late detection
• WSL browser wrapper behavior
• unsafe URL rejection
• az login interactive auth-code path using the WSL browser wrapper

History Notes

[Profile] az login: Fix misleading WSLInterop disabled errors during browser login on WSL

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• Fixes Misleading error about WSLInterop #33931

[azure-client-tools-bot-prd]

Hi Copilot,
Since the current milestone time is less than 7 days, this pr may not catch up with this release.

[azure-pipelines]

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[Copilot]

Copilot wasn't able to review any files in this pull request.

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[azure-pipelines]

Azure Pipelines:
There may be pipelines that require an authorized user to comment /azp run to run.

[azure-client-tools-agent]

Live test skipped

⏭️ Skipping the live test for this revision because the only test file(s) changed are azure-cli-core unit tests, which the live-test pipeline (azdev test --live) does not run — it covers command-module and extension tests only.

These azure-cli-core tests are exercised by upstream CI's unit-test jobs instead. This is informational; no action is required.

[azure-client-tools-agent]

Automated Review Summary — PR #33932

Live test: Skipped — the only changed test file is an azure-cli-core unit test, which is not runnable via azdev test --live. Not a gap in coverage; unit tests are exercised by upstream CI instead.

CI checks: ✅ All passed (1/1 completed, 0 failed, 0 pending).

No outstanding issues found. This PR looks ready for human maintainer review/merge.

[microsoft-github-policy-service]

🔔 Routing this PR to @Azure/act-identity-squad.

[Yong Zhang (yonzhan)]

az login