Fail cleanly when AppHost selection needs a prompt in non-interactive mode (#17619)

[mitchdenny]

Description

Fixes #17619 — aspire describe --non-interactive (and other backchannel commands) crashes by attempting an interactive AppHost-selection prompt when no AppHost can be unambiguously resolved.

Root cause

When AppHostConnectionResolver found multiple in-scope AppHosts, or only out-of-scope AppHosts, it always fell through to an interactive selection prompt. In non-interactive mode there is no console to prompt on, so the prompt threw instead of returning a clean error.

Fix

• AppHostConnectionResolver now takes an ICliHostEnvironment and checks SupportsInteractiveInput before prompting:
  • Multiple in-scope AppHosts, non-interactive → returns an actionable error (MultipleAppHostsNonInteractive) with FailedToFindProject instead of throwing.
  • Only out-of-scope AppHosts, non-interactive → returns the standard "not found" error/exit code instead of an unexpected prompt failure.
• Wired the ICliHostEnvironment through every caller (DescribeCommand, ExportCommand, LogsCommand, StopCommand, telemetry/MCP/resource/wait commands, and the terminal attach/ps commands).
• Added a new MultipleAppHostsNonInteractive resource string (+ generated .xlf placeholders).

Tests

Adds AppHostConnectionResolverTests coverage for both non-interactive branches (only out-of-scope → not found; multiple in-scope → actionable error).

Split out of #18261 so each fix can be reviewed in isolation.

Fixes #17619

[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 18297

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 18297"

[Copilot]

Pull request overview

This PR fixes a crash in aspire describe --non-interactive (and other backchannel commands) that occurred when the CLI attempted an interactive AppHost-selection prompt in non-interactive mode. The fix adds early detection of non-interactive mode in AppHostConnectionResolver and returns clean, actionable error messages instead of letting the prompt throw.

Changes:

• Added non-interactive guards in AppHostConnectionResolver.ResolveConnectionAsync for two prompt paths (multiple in-scope AppHosts and only out-of-scope AppHosts), returning descriptive errors with CliExitCodes.FailedToFindProject.
• Wired ICliHostEnvironment through CommonCommandServices and all 12 command call sites that construct AppHostConnectionResolver.
• Added a new MultipleAppHostsNonInteractive resource string with all localization .xlf placeholders, and two targeted unit tests.

Show a summary per file

File	Description
src/Aspire.Cli/Backchannel/AppHostConnectionResolver.cs	Core fix: checks hostEnvironment.SupportsInteractiveInput before prompting; accepts new ICliHostEnvironment parameter
src/Aspire.Cli/Commands/CommonCommandServices.cs	Adds ICliHostEnvironment hostEnvironment as a required constructor parameter with a public property
src/Aspire.Cli/Commands/DescribeCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/ExportCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/LogsCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/StopCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/ResourceCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/WaitCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/McpCallCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/McpToolsCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/TelemetryLogsCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/TelemetrySpansCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/TelemetryTracesCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/TerminalAttachCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Commands/TerminalPsCommand.cs	Passes services.HostEnvironment to resolver
src/Aspire.Cli/Resources/SharedCommandStrings.resx	New MultipleAppHostsNonInteractive resource string
src/Aspire.Cli/Resources/SharedCommandStrings.Designer.cs	Generated property for new resource string
src/Aspire.Cli/Resources/xlf/*.xlf (13 files)	Localization placeholders for the new string
tests/Aspire.Cli.Tests/Backchannel/AppHostConnectionResolverTests.cs	Two new tests for non-interactive branches + updates existing tests with new parameter
tests/Aspire.Cli.Tests/NuGet/NuGetPackagePrefetcherTests.cs	Adds 8th null! for the new CommonCommandServices parameter

Copilot's findings

Files not reviewed (1)

• src/Aspire.Cli/Resources/SharedCommandStrings.Designer.cs: Generated file

• Files reviewed: 31/32 changed files
• Comments generated: 0

[JamesNK]

Clean fix. Both non-interactive prompt paths are correctly guarded, all call sites updated consistently, DI wiring is intact, and the two new tests cover both branches. No issues found.

[mitchdenny]

PR Testing note — #18297 (merged)

This PR is already MERGED (bf0c0ef), so a fresh dogfood artifact isn't produced for it. Its non-interactive behavior was exercised incidentally while dogfood-testing the stacked #18298 build (which sits on top of this fix): every aspire describe … --non-interactive invocation in that run completed cleanly — no "Failed to read input in non-interactive mode" crash and no hang when AppHost selection would otherwise prompt. No issues observed.