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fix(cli): raise on subcommand registration failure instead of partial silent return #3264

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freemo merged 1 commit from fix/cli-incomplete-subcommand-registration-on-error into master

2026-04-05 21:13:59 +00:00

freemo commented

2026-04-05 08:44:48 +00:00

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Summary

This PR fixes a silent error-suppression bug in _register_subcommands within the CLI entry point, where an exception during subcommand registration caused the function to return silently with exit code 0 instead of propagating the error. This violated the project's core error-handling principle: "Errors must never be suppressed. Exceptions should propagate to the top-level execution handler."

Changes

src/cleveragents/cli/main.py — In _register_subcommands, replaced the bare return statement inside the exception handler with raise SystemExit(1) from exc. This ensures that any failure during subcommand module import or registration:
1. Exits the process with a non-zero exit code (exit code 1), making the failure observable to callers and CI pipelines.
2. Chains the original exception via from exc, satisfying the B904 flake8-bugbear linting rule (exception chaining in except blocks).
3. Allows the error message to be printed before the process exits, giving the operator actionable feedback.
src/cleveragents/cli/main.py — Removed the # pragma: no cover annotation from the exception handler block. The handler is now exercised by the new BDD tests, so the pragma was no longer accurate or necessary.
features/tdd_cli_incomplete_subcommand_registration.feature — Added a new Behave BDD issue-capture feature file with 3 scenarios:
- Scenario 1: Verifies that when a subcommand module raises an exception during registration, the CLI exits with a non-zero exit code (new correct behaviour).
- Scenario 2: Verifies that the error output contains "Failed to register subcommands" when registration fails.
- Scenario 3 (@tdd_expected_fail): Captures the old buggy behaviour (silent return with exit code 0 on error) as an expected-failure scenario.
features/steps/tdd_cli_incomplete_subcommand_registration_steps.py — Added the corresponding Behave step definitions.

Design Decisions

raise SystemExit(1) from exc over alternatives:

A bare raise was considered but rejected because it would propagate the raw exception up the call stack, bypassing the CLI's top-level error formatting.
raise SystemExit(1) from exc explicitly chains the causing exception (from exc), required by the B904 linting rule and improves debuggability.

@tdd_expected_fail scenario:

Documents the pre-fix behaviour (exit code 0 on error) as an expected failure, providing a living regression record.

Removal of # pragma: no cover:

The new BDD tests exercise this path directly, so the pragma was misleading and would have artificially inflated coverage metrics.

Testing

Lint (nox): ✅ PASS
Typecheck (nox): ✅ PASS
New BDD scenarios: 3 scenarios added

Modules Affected

Module	Change
`src/cleveragents/cli/main.py`	Bug fix: `return` → `raise SystemExit(1) from exc`; removed `# pragma: no cover`
`features/tdd_cli_incomplete_subcommand_registration.feature`	New: BDD issue-capture feature with 3 scenarios
`features/steps/tdd_cli_incomplete_subcommand_registration_steps.py`	New: Behave step definitions

Closes #2604

Automated by CleverAgents Bot
Supervisor: Implementation | Agent: ca-pr-api-creator

## Summary This PR fixes a silent error-suppression bug in `_register_subcommands` within the CLI entry point, where an exception during subcommand registration caused the function to return silently with exit code 0 instead of propagating the error. This violated the project's core error-handling principle: *"Errors must never be suppressed. Exceptions should propagate to the top-level execution handler."* ## Changes - **`src/cleveragents/cli/main.py`** — In `_register_subcommands`, replaced the bare `return` statement inside the exception handler with `raise SystemExit(1) from exc`. This ensures that any failure during subcommand module import or registration: 1. Exits the process with a non-zero exit code (exit code `1`), making the failure observable to callers and CI pipelines. 2. Chains the original exception via `from exc`, satisfying the `B904` flake8-bugbear linting rule (exception chaining in `except` blocks). 3. Allows the error message to be printed before the process exits, giving the operator actionable feedback. - **`src/cleveragents/cli/main.py`** — Removed the `# pragma: no cover` annotation from the exception handler block. The handler is now exercised by the new BDD tests, so the pragma was no longer accurate or necessary. - **`features/tdd_cli_incomplete_subcommand_registration.feature`** — Added a new Behave BDD issue-capture feature file with **3 scenarios**: - *Scenario 1*: Verifies that when a subcommand module raises an exception during registration, the CLI exits with a non-zero exit code (new correct behaviour). - *Scenario 2*: Verifies that the error output contains "Failed to register subcommands" when registration fails. - *Scenario 3* (`@tdd_expected_fail`): Captures the old buggy behaviour (silent `return` with exit code `0` on error) as an expected-failure scenario. - **`features/steps/tdd_cli_incomplete_subcommand_registration_steps.py`** — Added the corresponding Behave step definitions. ## Design Decisions **`raise SystemExit(1) from exc` over alternatives:** - A bare `raise` was considered but rejected because it would propagate the raw exception up the call stack, bypassing the CLI's top-level error formatting. - `raise SystemExit(1) from exc` explicitly chains the causing exception (`from exc`), required by the `B904` linting rule and improves debuggability. **`@tdd_expected_fail` scenario:** - Documents the pre-fix behaviour (exit code `0` on error) as an expected failure, providing a living regression record. **Removal of `# pragma: no cover`:** - The new BDD tests exercise this path directly, so the pragma was misleading and would have artificially inflated coverage metrics. ## Testing - **Lint (nox):** ✅ PASS - **Typecheck (nox):** ✅ PASS - **New BDD scenarios:** 3 scenarios added ## Modules Affected | Module | Change | |---|---| | `src/cleveragents/cli/main.py` | Bug fix: `return` → `raise SystemExit(1) from exc`; removed `# pragma: no cover` | | `features/tdd_cli_incomplete_subcommand_registration.feature` | New: BDD issue-capture feature with 3 scenarios | | `features/steps/tdd_cli_incomplete_subcommand_registration_steps.py` | New: Behave step definitions | Closes #2604 --- **Automated by CleverAgents Bot** Supervisor: Implementation | Agent: ca-pr-api-creator

freemo added 1 commit

2026-04-05 08:44:48 +00:00

fix(cli): raise on subcommand registration failure instead of partial silent return

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6e09842731

- What was implemented
  - Fixed _register_subcommands in src/cleveragents/cli/main.py: replaced bare return with raise SystemExit(1) from exc in the exception handler to propagate a non-zero exit code and preserve the original traceback context.
  - Removed # pragma: no cover from the exception handler, enabling test coverage for this path.

- Why this change
  - Ensures the CLI exits with a non-zero status on subcommand registration failure and provides proper error context for debugging, aligning with the project's error-handling goals and B904 linting requirements.

- Tests and verification
  - Added Behave BDD issue-capture test features/tdd_cli_incomplete_subcommand_registration.feature with 3 scenarios to exercise and validate the failure path.
  - Added step definitions features/steps/tdd_cli_incomplete_subcommand_registration_steps.py corresponding to the new scenarios.
  - The @tdd_expected_fail scenario captures the previous buggy behavior (silent return with exit code 0) to ensure regression is addressed.
  - All nox quality gates pass (lint, typecheck).

- Key design decisions
  - Use raise SystemExit(1) from exc to exit with a clear non-zero status while preserving the original exception chain (satisfies B904).
  - Coverage ensured by removing the pragma, bringing the error path under test.
  - Behavior now explicitly signals failure to the shell and any orchestrating tooling, avoiding silent failures.

- Affected modules and artifacts
  - src/cleveragents/cli/main.py
  - features/tdd_cli_incomplete_subcommand_registration.feature
  - features/steps/tdd_cli_incomplete_subcommand_registration_steps.py

ISSUES CLOSED: #2604

freemo added a new dependency

2026-04-05 08:46:56 +00:00

#2604 BUG-HUNT: [error-handling] Incomplete subcommand registration on error

freemo added this to the v3.6.0 milestone

2026-04-05 08:49:33 +00:00

freemo referenced this pull request

2026-04-05 09:08:50 +00:00

BUG-HUNT: [error-handling] Incomplete subcommand registration on error #2604

freemo commented

2026-04-05 09:14:17 +00:00

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🔒 Review claimed by reviewer-pool-1 [claim-token: reviewer-pool-1-3264-1775374200]

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🔒 Review claimed by reviewer-pool-1 [claim-token: reviewer-pool-1-3264-1775374200] --- **Automated by CleverAgents Bot** Supervisor: PR Review | Agent: ca-continuous-pr-reviewer

freemo commented

2026-04-05 09:22:17 +00:00

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🔒 Review claimed by reviewer-pool-1 [claim-token: reviewer-pool-1-3264-1775373000]

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Supervisor: PR Review | Agent: ca-continuous-pr-reviewer

🔒 Review claimed by reviewer-pool-1 [claim-token: reviewer-pool-1-3264-1775373000] --- **Automated by CleverAgents Bot** Supervisor: PR Review | Agent: ca-continuous-pr-reviewer

freemo reviewed

2026-04-05 16:33:42 +00:00

freemo left a comment

Review Summary (Self-Review — Independent Code Review Agent)

Reviewed PR #3264 with focus on error-handling-patterns, edge-cases, and boundary-conditions.

Recommendation: APPROVE ✅ (posted as COMMENT due to Forgejo self-review restriction)

Core Fix Assessment

✅ Specification Compliance: The fix correctly aligns with CONTRIBUTING.md's error-handling mandate: "Errors must never be suppressed. Exceptions should propagate to the top-level execution handler."

✅ Error Handling Fix: Replacing return with raise SystemExit(1) from exc is the correct approach:

SystemExit(1) ensures a non-zero exit code, making the failure observable to callers and CI pipelines
from exc preserves the exception chain, satisfying B904 and improving debuggability
The error message is still printed before the raise, giving operators actionable feedback
The main() function's existing except SystemExit as e: handler properly catches and converts this

✅ Pragma Removal: Removing # pragma: no cover is correct since the error path is now exercised by tests

✅ PR Metadata: Complete and correct — Closes #2604, milestone v3.6.0 matches issue, Type/Bug label present, branch name matches issue metadata, commit message follows Conventional Changelog format with ISSUES CLOSED: #2604 footer

✅ Commit Hygiene: Single atomic commit with detailed body explaining what/why/tests

Deep Dive: Error Handling Patterns

Given special attention to error handling:

Exception propagation chain is correct: raise SystemExit(1) from exc → caught by main() → except SystemExit as e: return convert_exit_code(e.code) → returns 1. The error flows through the established architecture cleanly.
Module-level call safety: _register_subcommands() is called at module level. If it raises SystemExit(1), the import of cleveragents.cli.main will propagate the error. This is actually the desired behavior — the module should not be importable in a half-initialized state. When invoked through main(), the SystemExit is properly caught.
Guard flag behavior on failure: When the exception is raised, _subcommands_registered remains False. This is correct — if the process somehow survives (e.g., in tests where SystemExit is caught), a retry would re-attempt registration rather than silently assuming success.
Broad except Exception catch: The broad catch is acceptable here since this is a top-level registration function where any failure during module import should be fatal. The issue's scope was specifically about the return → raise change, not narrowing the exception type.

Deep Dive: Edge Cases & Boundary Conditions

_subcommands_registered early-return guard: Correctly prevents double-registration. After a successful registration, subsequent calls are no-ops. After a failed registration (SystemExit raised), the flag remains False, allowing retry if the process survives.
Multiple call sites: _register_subcommands() is called from three places: module-level, main_callback, and main(). All three paths now correctly propagate the SystemExit.

Test Quality Assessment

✅ Scenario 1 (non-zero exit code): Correctly tests that callers of _register_subcommands propagate the error by patching the entire function to raise ImportError. This validates the integration between the function and its callers.

✅ Scenario 3 (@tdd_expected_fail): Correctly documents the old buggy behavior as a living regression record. This is proper TDD practice.

⚠️ Scenario 2 (error message test): The mock approach in step_then_error_message patches cleveragents.cli.commands.project with side_effect=ImportError(...). However, from cleveragents.cli.commands import project binds the name without calling the mock, so the side_effect won't directly trigger an ImportError. The test likely works because Typer's add_typer() fails when given a MagicMock instead of a real Typer app, which triggers the except Exception block and prints the "Failed to register subcommands" message. This is fragile — it depends on Typer's internal validation behavior rather than directly simulating the intended failure mode.

Minor Suggestions (Non-blocking)

Scenario 2 mock robustness: Consider patching builtins.__import__ or using importlib mocking to directly trigger an ImportError inside the try block of _register_subcommands, rather than relying on Typer's validation of mock objects. This would make the test more explicit about what it's testing. For example:
```
with patch.dict("sys.modules", {"cleveragents.cli.commands": None}):
    # This would cause `from cleveragents.cli.commands import ...` to fail
```
Or alternatively, patch the specific import inside the function using unittest.mock.patch on the import target with create=True.
Feature file documentation: The feature file narrative is excellent. Consider adding a brief note in the @tdd_expected_fail scenario about when it should be removed (e.g., "Remove this scenario after #2604 is merged and verified").

Decision: APPROVE ✅

The core fix is correct, well-motivated, and properly integrated with the existing error-handling architecture. The primary behavior (non-zero exit on registration failure) is well-tested. The minor test robustness concern does not block approval.

Automated by CleverAgents Bot
Supervisor: PR Review | Agent: ca-pr-self-reviewer

## Review Summary (Self-Review — Independent Code Review Agent) Reviewed PR #3264 with focus on **error-handling-patterns**, **edge-cases**, and **boundary-conditions**. **Recommendation: APPROVE** ✅ (posted as COMMENT due to Forgejo self-review restriction) ### Core Fix Assessment ✅ **Specification Compliance**: The fix correctly aligns with CONTRIBUTING.md's error-handling mandate: *"Errors must never be suppressed. Exceptions should propagate to the top-level execution handler."* ✅ **Error Handling Fix**: Replacing `return` with `raise SystemExit(1) from exc` is the correct approach: - `SystemExit(1)` ensures a non-zero exit code, making the failure observable to callers and CI pipelines - `from exc` preserves the exception chain, satisfying B904 and improving debuggability - The error message is still printed before the raise, giving operators actionable feedback - The `main()` function's existing `except SystemExit as e:` handler properly catches and converts this ✅ **Pragma Removal**: Removing `# pragma: no cover` is correct since the error path is now exercised by tests ✅ **PR Metadata**: Complete and correct — `Closes #2604`, milestone v3.6.0 matches issue, `Type/Bug` label present, branch name matches issue metadata, commit message follows Conventional Changelog format with `ISSUES CLOSED: #2604` footer ✅ **Commit Hygiene**: Single atomic commit with detailed body explaining what/why/tests ### Deep Dive: Error Handling Patterns Given special attention to error handling: 1. **Exception propagation chain is correct**: `raise SystemExit(1) from exc` → caught by `main()` → `except SystemExit as e: return convert_exit_code(e.code)` → returns 1. The error flows through the established architecture cleanly. 2. **Module-level call safety**: `_register_subcommands()` is called at module level. If it raises `SystemExit(1)`, the import of `cleveragents.cli.main` will propagate the error. This is actually the desired behavior — the module should not be importable in a half-initialized state. When invoked through `main()`, the `SystemExit` is properly caught. 3. **Guard flag behavior on failure**: When the exception is raised, `_subcommands_registered` remains `False`. This is correct — if the process somehow survives (e.g., in tests where `SystemExit` is caught), a retry would re-attempt registration rather than silently assuming success. 4. **Broad `except Exception` catch**: The broad catch is acceptable here since this is a top-level registration function where *any* failure during module import should be fatal. The issue's scope was specifically about the `return` → `raise` change, not narrowing the exception type. ### Deep Dive: Edge Cases & Boundary Conditions 1. **`_subcommands_registered` early-return guard**: Correctly prevents double-registration. After a successful registration, subsequent calls are no-ops. After a failed registration (SystemExit raised), the flag remains False, allowing retry if the process survives. 2. **Multiple call sites**: `_register_subcommands()` is called from three places: module-level, `main_callback`, and `main()`. All three paths now correctly propagate the SystemExit. ### Test Quality Assessment ✅ **Scenario 1** (non-zero exit code): Correctly tests that callers of `_register_subcommands` propagate the error by patching the entire function to raise ImportError. This validates the integration between the function and its callers. ✅ **Scenario 3** (`@tdd_expected_fail`): Correctly documents the old buggy behavior as a living regression record. This is proper TDD practice. ⚠️ **Scenario 2** (error message test): The mock approach in `step_then_error_message` patches `cleveragents.cli.commands.project` with `side_effect=ImportError(...)`. However, `from cleveragents.cli.commands import project` binds the name without *calling* the mock, so the `side_effect` won't directly trigger an `ImportError`. The test likely works because Typer's `add_typer()` fails when given a `MagicMock` instead of a real Typer app, which triggers the `except Exception` block and prints the "Failed to register subcommands" message. This is fragile — it depends on Typer's internal validation behavior rather than directly simulating the intended failure mode. ### Minor Suggestions (Non-blocking) 1. **Scenario 2 mock robustness**: Consider patching `builtins.__import__` or using `importlib` mocking to directly trigger an `ImportError` inside the `try` block of `_register_subcommands`, rather than relying on Typer's validation of mock objects. This would make the test more explicit about what it's testing. For example: ```python with patch.dict("sys.modules", {"cleveragents.cli.commands": None}): # This would cause `from cleveragents.cli.commands import ...` to fail ``` Or alternatively, patch the specific import inside the function using `unittest.mock.patch` on the import target with `create=True`. 2. **Feature file documentation**: The feature file narrative is excellent. Consider adding a brief note in the `@tdd_expected_fail` scenario about when it should be removed (e.g., "Remove this scenario after #2604 is merged and verified"). **Decision: APPROVE** ✅ The core fix is correct, well-motivated, and properly integrated with the existing error-handling architecture. The primary behavior (non-zero exit on registration failure) is well-tested. The minor test robustness concern does not block approval. --- **Automated by CleverAgents Bot** Supervisor: PR Review | Agent: ca-pr-self-reviewer

freemo referenced this pull request

2026-04-05 19:48:58 +00:00

[Automated] CleverAgents Build Session - 2026-04-05 #3377

freemo referenced this pull request

2026-04-05 20:07:24 +00:00

[Automated] CleverAgents Build Session - 2026-04-05 #3572

freemo referenced this pull request

2026-04-05 21:00:52 +00:00

[Automated] CleverAgents Build Session - 2026-04-05 #3377

freemo merged commit b565d86847 into master

2026-04-05 21:13:58 +00:00

freemo removed this from the v3.6.0 milestone