fix: compose up must exit non-zero when the AI debugger runs

[defangdevs]

Fixes #2227.

The bug

handleComposeUpErr returned the debugger's error:

return debugger.DebugDeploymentError(ctx, debug.DebugConfig{Project: project}, originalErr)

promptAndTrackDebugSession returns nil once the debug session finishes, so a
fatal ComposeUp error came back as nil and the CLI exited 0.

It only bites accounts that auto-approve the debugger. The guard above it,
if global.NonInteractive && !debugger.AutoApprove(), sends free-tier CI
straight out with the error — so the false green hits exactly the paid accounts
whose CI runs the debugger unattended, including Defang's own.

The fix

Run the debugger for its side effect and always return the deployment error.
That is the shape the neighbouring paths already use: handleTailAndMonitorErr
returns nothing and its caller returns deploymentErr, and session.go returns
loadErr after DebugComposeLoadError.

handleTooManyProjectsError still returns nil after a successful interactive
compose down — that one is a deliberate recovery, and it is untouched.

Tests

TestHandleComposeUpErrKeepsTheDeploymentError covers the CI auto-approve path
for both a debugger that succeeds and one that fails;
TestHandleComposeUpErrWithoutAutoApprove covers the free-tier path. Reverting
the one-line change fails the first with expected the original deployment error, got <nil> — the reported symptom exactly.

NewDebuggerForTest is new: NewDebugger needs a live Fabric connection, so
tests outside pkg/debug had no way to build a Debugger.

🤖 Generated with Claude Code

https://claude.ai/code/session_01T3WmpdY3zc555sNdkY9dzQ

Summary by CodeRabbit

• Bug Fixes
  • Deployment failures now consistently return the original error, even when automated debugging is enabled.
  • Debugger issues no longer mask failed deployments or incorrectly produce successful command exits.
  • Improved error handling across both automatic and non-automatic debugging flows.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 5b7cee71-60c8-4700-b49a-c3a2f2798022

📥 Commits

Reviewing files that changed from the base of the PR and between d8aa2a0 and 81bdb17.

📒 Files selected for processing (3)

• src/cmd/cli/command/compose.go
• src/cmd/cli/command/compose_test.go
• src/pkg/debug/debug.go

Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review.

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📝 Walkthrough

Walkthrough

The compose error handler now returns the deployment error after debugger execution. Debugger failures are logged. Tests cover auto-approve and non-auto-approve account paths using an injectable debugger agent.

Changes

Compose error preservation

Layer / File(s)	Summary
Preserve deployment errors src/cmd/cli/command/compose.go	handleComposeUpErr logs debugger failures and always returns the original compose deployment error.
Regression coverage and test debugger construction src/pkg/debug/debug.go, src/cmd/cli/command/compose_test.go	NewDebuggerForTest enables debugger injection. Tests verify deployment error preservation and debugger invocation behavior for auto-approve and non-auto-approve paths.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 81bdb

The CLI will now exit non-zero when compose deployment fails even if the AI debugger runs; the localized change is covered by focused tests, and no actionable merge-blocking risk remains.

Suggested reviewers: lionello

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 42.86% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the fix that prevents compose up from exiting successfully after the AI debugger runs.
Linked Issues check	✅ Passed	The change preserves the deployment error and adds regression tests for the affected debugger paths described in issue #2227.
Out of Scope Changes check	✅ Passed	The production fix, regression tests, and test-only debugger constructor all support the requirements in issue #2227.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/2227-compose-up-exit-code

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