Improve AppHost debug console output for TS and C#

[adamint]

Description

Several related fixes for VS Code extension AppHost debug-console output and startup failure handling.

1. Filter debugger noise from the parent debug console

When a C# AppHost runs as a child debug session, the .NET debugger writes module-load messages, exception-thrown notifications, banner text, launch-profile messages, and other console/debug DAP output into the Aspire parent debug console.

This PR filters that noise while keeping real runtime output. Low-level AppHost logs (trce/dbug, Trace/Debug) are dropped, while severe output (fail/crit, Error/Critical, uncaught exceptions, fatal lines, and continuations) is preserved and shown on stderr.

2. Surface guest AppHost failures before launch

TypeScript/Node AppHosts can fail in a pre-launch step, such as tsc --noEmit, before the AppHost and backchannel are started. Previously the extension could stay stuck at Connecting to AppHost... without showing the compilation error.

Now the CLI checks that failure path before waiting for the extension launcher, displays the captured guest output, and completes the backchannel wait with an error so the run exits cleanly.

3. Clean up AppHost debug-console output

CLI stdout/stderr from the extension host is now buffered by line and decoded as UTF-8, so output is not split mid-line or mid-emoji. Captured DisplayLines output is sent through the extension backchannel without also being written to captured stdout/stderr, which avoids duplicate lines and keeps failure details ordered before follow-up error/log messages.

Stderr is no longer blindly prefixed as an error by the extension; CLI/Spectre already adds the appropriate error prefix when output is actually an error.

4. Fix smaller extension-host UX issues

This also stops aspire describe --follow from restarting forever when it exits before producing data, anchors CodeLens state/actions above single-resource fluent chains, and renders the AppHost/log summary without terminal-style indentation or blank separator rows in extension-host mode.

Verified with:

• ./dotnet.sh build src/Aspire.Cli/Aspire.Cli.csproj /p:SkipNativeBuild=true
• npm run compile-tests
• npm run unit-test | grep -A3 "AspireCodeLensProvider resource lens anchoring"

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
  • No
• Does the change require an update in our Aspire docs?
  • Yes
  • No

[Copilot]

Pull request overview

This PR reduces noise in the VS Code Aspire parent debug console when an AppHost is launched as a child debug session by filtering debug-adapter “output” events and suppressing low-signal debugger chatter while preserving/promoting severe runtime output.

Changes:

• Added AppHostParentOutputFilter to drop debug output, aggressively filter console output, and suppress/promote AppHost stdout/stderr log lines based on severity (including indented continuations).
• Updated AppHost output tracking so the raw DAP category value reaches the filter (instead of being coerced to only stdout/stderr).
• Added unit tests covering noise vs. keep cases (including localized debugger banner lines and Node.js exception shapes).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
extension/src/test/dotnetDebugger.test.ts	Adds unit tests validating AppHost output filtering behavior (drop noise, keep/promote fatal output, keep normal output).
extension/src/debugger/AspireDebugSession.ts	Introduces and uses AppHostParentOutputFilter to filter/mirror AppHost debug-session output into the parent debug console.
extension/src/debugger/adapterTracker.ts	Broadens AppHost output callback to pass through the raw DAP category for filtering.

[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 -- 16795

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/microsoft/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 16795"

[github-actions]

Re-running the failed jobs in the CI workflow for this pull request because 1 job was identified as retry-safe transient failures in the CI run attempt.
GitHub was asked to rerun all failed jobs for that attempt, and the rerun is being tracked in the rerun attempt.
The job links below point to the failed attempt jobs that matched the retry-safe transient failure rules.

• Tests / Hosting-5 / Hosting-5 (windows-latest) - Job-level runner or infrastructure failure matched the transient allowlist.

[danegsta]

Posted 1 code review comment.

[danegsta]

The DAP category is optional, and adapterTracker.ts documents that a missing category should be treated as console, but this filter currently leaves undefined unchanged. That lets category-less C# AppHost debug-adapter output bypass the category === 'console' && !isSevereOutput suppression path and get mirrored as stdout, so debugger noise can reappear. Normalize once at the boundary (for example, const normalizedCategory = category ?? 'console') and use that for state tracking and line classification.

[adamint]

Good catch — fixed in 382009c. I now normalize category ?? 'console' once at the top of AppHostParentOutputFilter.filter and propagate that normalized value through _lastCategory, the hasErrorOutput seed, and getLineCategory / shouldMirrorConsoleOutput / getCurrentCategory (whose parameter type is now string since they only see normalized values). Added a regression test in dotnetDebugger.test.ts covering both undefined-category debugger noise (suppressed) and undefined-category severe runtime output (kept and promoted to stderr) so the console-suppression path can no longer be bypassed.

[adamint]

/backport to release/13.3

[github-actions]

Started backporting to release/13.3 (link to workflow run)

[aspire-repo-bot]

@adamint backporting to release/13.3 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch

Applying: Filter AppHost debugger noise from Aspire parent debug console
Using index info to reconstruct a base tree...
M	extension/src/debugger/AspireDebugSession.ts
M	extension/src/debugger/adapterTracker.ts
M	extension/src/test/dotnetDebugger.test.ts
Falling back to patching base and 3-way merge...
Auto-merging extension/src/debugger/AspireDebugSession.ts
CONFLICT (content): Merge conflict in extension/src/debugger/AspireDebugSession.ts
Auto-merging extension/src/debugger/adapterTracker.ts
CONFLICT (content): Merge conflict in extension/src/debugger/adapterTracker.ts
Auto-merging extension/src/test/dotnetDebugger.test.ts
CONFLICT (content): Merge conflict in extension/src/test/dotnetDebugger.test.ts
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0001 Filter AppHost debugger noise from Aspire parent debug console
Error: The process '/usr/bin/git' failed with exit code 128

Link to workflow output