[MikeMcQuaid]

• Fail promptly when SSH cannot decrypt a private key instead of waiting for input hidden by concurrent download output.
• Preserve sandbox permissions and existing SSH agent support.

Fixes #24115

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Codex with GPT 6 Astra at Extra High effort, with local review and testing.

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[Copilot]

Copilot review overview

🟢 Approval recommended

No unresolved blocking issues were identified.

Review effort: Lite
Findings: None

What changed in this PR

Prevents sandboxed Git fetches from hanging on SSH passphrase prompts while preserving SSH agent support.

Changes:

• Forces non-interactive SSH askpass failures.
• Adds regression coverage for encrypted SSH keys and environment preservation.

File	Description
Library/​Homebrew/​test/​download_strategies/​git_spec.rb	Tests prompt-free SSH failure behavior and preserved environment values.
Library/​Homebrew/​download_strategy/​git_download_strategy.rb	Configures non-interactive SSH handling during sandboxed fetches.

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