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fix(cli): detect Windows USB serial ports in ebuild monitor - #185
fix(cli): detect Windows USB serial ports in ebuild monitor
Summary
Auto-detection of serial devices in ebuild monitor previously only searched POSIX device paths (/dev/ttyUSB*, /dev/ttyACM*, /dev/tty.usb*). On Windows, boards appear as COMn ports that can only be enumerated through pyserial, so the command reported "No serial device found" even when a board was attached. This PR adds Windows COM port discovery and improves how a missing pyserial dependency is reported.
Changes
Serial port detection (ebuild/cli/commands.py)
_serial_ports() now also enumerates ports through serial.tools.list_ports.comports() and includes entries whose device name starts with COM and that report a vendor ID (vid). Ports without a vendor ID (built-in COM1, Bluetooth serial ports) are excluded, since including them would make auto-detection ambiguous — the same reason /dev/ttyS* is not searched.
Discovered COM ports are sorted by name length first, then lexicographically, so COM2 is offered before COM10.
Non-COM devices returned by pyserial (for example /dev/ttyUSB0 on Linux) are ignored, since the existing glob search already finds them.
If pyserial is unavailable, the function returns whatever the POSIX glob search found instead of failing.
monitor command behavior
The pyserial import check now runs before auto-detection rather than immediately before opening the port. Without pyserial, Windows COM ports cannot be discovered, so the old ordering produced a misleading "No serial device found" error. The command now exits with a clear message: pyserial is not installed... Install it with: pip install pyserial.
The "no device found" error message now mentions USB COM ports in addition to the POSIX patterns.
The --port option help text now shows COM3 as an example alongside /dev/ttyUSB0.
Tests (tests/unit/cli/test_serial_ports.py, new)
Adds unit coverage for the new behavior:
COM enumeration keeps only USB devices (built-in and Bluetooth ports filtered out).
COM ports sort numerically (COM2, COM3, COM10).
Non-COM devices reported by pyserial are ignored.
POSIX ports are still found when pyserial is not installed.
monitor reports the missing-pyserial error before attempting detection (exit code 1).
monitor auto-detects and opens a single USB COM port.
monitor refuses to guess when more than one USB COM port is present (exit code 1).
Review Findings
The automated review raised two medium-severity items:
ebuild/cli/commands.py:3094 — the ImportError in _serial_ports during COM enumeration is swallowed silently, with no diagnostic emitted.
The PR body has no linked issue or closing keyword.
Notes
No linked issue is referenced in this description.
Summary by Sourcery
Enable reliable Windows USB serial-port detection in ebuild monitor while preserving existing POSIX behavior.
New Features:
Add automatic detection of USB COM serial ports for Windows boards in ebuild monitor.
Filter detected COM ports to USB devices and select them in a deterministic order.
Bug Fixes:
Report missing pyserial before Windows auto-detection and preserve POSIX detection when the dependency is unavailable.
Clarify monitor guidance for Windows COM ports and missing serial devices.
Tests:
Add coverage for COM-port filtering, ordering, dependency handling, auto-detection, and ambiguous device selection.
Adjust monitor tests for environments where Windows pyserial is unavailable.
Summary by CodeRabbit
New Features
The monitor command can detect USB COM ports on Windows and automatically connect when exactly one eligible port is found.
Port help and no-device messages now include Windows COM-port guidance.
Bug Fixes
On Windows, the monitor command reports when serial-port support is unavailable before attempting automatic detection.
The command reports an error when multiple USB COM ports prevent an unambiguous automatic selection.
Confidence Score: 5/5
The PR appears safe to merge; no blocking findings remain.
Summary
The PR adds Windows USB COM-port discovery to ebuild monitor.
ebuild monitor finds Windows USB serial ports automatically.
Monitor explains Windows port names and missing serial support.
No new actionable issues were found. Tests were not run; this review used the diffs and source.
Auto-detection only searched POSIX device paths, so `ebuild monitor`
could never find a board on Windows.
- Enumerate COM ports through pyserial, keeping only USB devices
(vid set) so built-in COM1 and Bluetooth ports do not make
auto-detection ambiguous, as /dev/ttyS* is skipped on POSIX.
- Sort COM ports numerically (COM2 before COM10).
- Check for pyserial before auto-detection, so a missing pyserial is
reported as such instead of "No serial device found".
- Mention COM ports in the not-found message and --port help.
- Add unit tests with a faked pyserial.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Updates ebuild monitor to discover USB-backed Windows COM ports through optional pyserial, filter and order candidates deterministically, provide clearer dependency and usage errors, and validate the behavior with focused unit tests.
Sequence diagram for monitor port auto-detection
sequenceDiagram
participant User
participant monitor
participant pyserial as pyserial
participant list_ports
participant Serial
User->>monitor: monitor(port=None, baud)
monitor->>pyserial: import serial
pyserial-->>monitor: available
monitor->>monitor: _serial_ports()
monitor->>list_ports: comports()
list_ports-->>monitor: COM port metadata
monitor->>monitor: filter USB ports by vid
monitor->>monitor: sort COM ports numerically
monitor->>Serial: Serial(selected_port, baud, timeout=0.2)
Serial-->>User: monitor serial output
Loading
Flow diagram for Windows serial port resolution
flowchart TD
A[ebuild monitor without --port] --> B{pyserial installed?}
B -- No --> C[Report missing pyserial and installation command]
B -- Yes --> D[_serial_ports]
D --> E[Enumerate POSIX device paths]
D --> F[Enumerate pyserial COM ports]
F --> G[Keep COM ports with a vendor ID]
G --> H[Sort COM ports by numeric name order]
E --> I{Candidates found?}
H --> I
I -- No --> J[Report POSIX and USB COM search paths]
I -- Yes --> K[Open selected port at requested baud]
Loading
File-Level Changes
Change
Details
Files
Add Windows USB COM-port discovery to monitor auto-detection while preserving POSIX discovery behavior.
Enumerate pyserial ports and retain only COM devices with a vendor ID.
Sort COM ports so numeric order is natural, such as COM2 before COM10.
Continue returning POSIX glob results when pyserial is unavailable.
ebuild/cli/commands.py
Improve dependency errors and user-facing guidance for serial monitoring.
Check for pyserial before auto-detection and report an actionable installation error.
Document COM-port syntax in --port help and no-device diagnostics.
ebuild/cli/commands.py
Cover Windows detection, filtering, ordering, fallback behavior, and monitor integration with unit tests.
Fake optional pyserial modules and serial connections in tests.
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monitor now discovers USB COM ports through pyserial while retaining POSIX device discovery. It reports when pyserial is unavailable and handles single or multiple detected devices.
Changes: Monitor port detection
Layer / File(s)
Summary
Port discovery and filtering ebuild/cli/commands.py, tests/unit/cli/test_serial_ports.py
_serial_ports retains POSIX discovery and adds USB COM-port enumeration. It excludes COM ports without a vendor ID and sorts the remaining ports by name length, then name. Tests cover filtering, sorting, and POSIX discovery behavior.
monitor checks for pyserial before Windows port selection, updates the port help and no-device message, and reports an error if pyserial is unavailable or multiple devices are found. Tests cover these cases, opening a sole USB COM port, and Windows skips when pyserial is unavailable.
sequenceDiagram
participant monitor
participant pyserial
participant _serial_ports
monitor->>pyserial: Check availability on Windows
monitor->>_serial_ports: Discover serial ports
_serial_ports->>pyserial: Enumerate USB COM ports
monitor->>monitor: Select and open the sole detected port
Loading
Merge Risk: Low · up to 3d6c3
The no-device test should isolate port discovery so connected Windows hardware cannot invalidate its result.
Pre-merge checks: 4 · 1
Failed checks: 1 warning
Check name
Status
Explanation
Resolution
Docstring Coverage
Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…
Write docstrings for the functions missing them to satisfy the coverage threshold.
Passed checks: 4 passed
Check name
Status
Explanation
Description Check
Check skipped - CodeRabbit’s high-level summary is enabled.
Title check
The title clearly and concisely describes the main change: adding Windows USB serial-port detection to ebuild monitor.
Linked Issues check
Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check
Check skipped because no linked issues were found for this pull request.
Full details: Docstring Coverage
Explanation
Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 4 functions across 2 files.
Resolution
Write docstrings for the functions missing them to satisfy the coverage threshold.
Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts
• Auto-detect USB COM ports on Windows while preserving POSIX device discovery.
• Report missing pyserial before detection and clarify port help and errors.
• Test filtering, ordering, detection, and ambiguous-port handling with fake pyserial.
The following are alternative approaches to this PR:
1. Use pyserial enumeration on every platform
➕ One discovery mechanism across operating systems.
➖ Could change existing POSIX detection, including which non-USB devices are offered.
➖ Would make discovery entirely dependent on pyserial.
Recommendation: Keep the PR's additive approach: it preserves POSIX discovery while using pyserial where COM-port enumeration is needed. The unified-enumeration alternative offers less duplication but risks changing established POSIX behavior.
Files changed (2) +193 / -12
Bug fix (1) +39 / -12
commands.pyAdd USB COM-port discovery to monitor+39/-12
Add USB COM-port discovery to monitor
• The monitor checks for pyserial before auto-detection, retains POSIX path discovery, and adds numerically ordered USB COM candidates while excluding non-USB ports. Help and not-found guidance now mention COM ports.
test_serial_ports.pyCover serial-port discovery and monitor decisions+154/-0
Cover serial-port discovery and monitor decisions
• New tests fake pyserial to verify USB filtering, COM ordering, POSIX behavior, missing-dependency reporting, single-port auto-detection, and refusal to guess between multiple ports.
View medium (1) 1. A Windows test can open a real board 🐞⭐
Description
The no_serial_devices fixture patches only glob.glob, while the new Windows skip condition
checks only whether pyserial is installed. On Windows with pyserial and an attached USB COM device,
_serial_ports() finds that device, causing the test to open the real port and enter the monitor
loop instead of reporting no device.
Agent prompt
The issue below was found during a code review. Follow the provided context and guidance below and implement a solution
## Issue description
The Windows skip condition allows `test_no_device_fails_cleanly` to run whenever pyserial is installed, but its fixture patches only POSIX glob enumeration. A connected USB COM device is then discovered through `list_ports.comports()`, potentially opening a real board and hanging the test.
## Fix Focus Areas
- tests/unit/test_monitor_command.py[23-26]
- tests/unit/test_monitor_command.py[43-48]
- ebuild/cli/commands.py[3167-3178]
## Recommended Fix
Extend the test fixture or add a Windows-specific fixture that mocks `serial.tools.list_ports.comports()` to return no ports, while preserving the existing POSIX glob mock. Ensure the no-device test controls both enumeration mechanisms rather than skipping only when pyserial is unavailable.
ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools
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Hey - I've found 4 issues
Prompt for AI Agents
Please address the comments from this code review:
## Individual Comments### Comment 1
<locationpath="ebuild/cli/commands.py"line_range="3101" />
<code_context>
++ com_ports = [+ port.device+ for port in list_ports.comports()+ if port.device.upper().startswith("COM") and port.vid is not None+]
</code_context>
<issue_to_address>
**USB output controls terminal**
When a malicious USB serial device with a non-null VID is connected and `monitor` runs without `--port`, `monitor` opens the auto-detected port and writes decoded serial bytes directly to stdout, so ANSI/OSC sequences from the device are interpreted by the developer’s terminal instead of displayed as text.
Escape or filter terminal control sequences before writing serial data to stdout.
</issue_to_address>
### Comment 2
<locationpath="ebuild/cli/commands.py"line_range="3103" />
<code_context>
+ port.device+ for port in list_ports.comports()+ if port.device.upper().startswith("COM") and port.vid is not None+]+# Sort by length first so COM2 precedes COM10.+ found.extend(sorted(com_ports, key=lambda d: (len(d), d)))
</code_context>
<issue_to_address>
**A reused COM number opens another device**
When a USB device disconnects after enumeration and another device is assigned the same COM number before the open, `monitor` keeps only the COM name returned by `_serial_ports()` and later opens it with `serial.Serial`; if the detected board disconnects and Windows assigns that COM number to another device in between, the monitor opens the replacement and displays its output as the board’s.
Retain and verify the enumerated device identity against the opened port, and abort if the identity changed.
</issue_to_address>
### Comment 3
<locationpath="tests/unit/cli/test_serial_ports.py"line_range="77" />
<code_context>
+ _port("COM4", None), # Bluetooth serial port+ _port("COM3", 0x10C4),+])
+ assert _serial_ports() == ["COM3"]++
</code_context>
<issue_to_address>
**Tests depend on a private helper**
When the serial-port unit tests run, the new tests call `_serial_ports()` directly to verify filtering and ordering instead of exercising the public monitor command, so those behaviors are coupled to a private implementation detail.
Verify these behaviors through the public `monitor` command rather than calling `_serial_ports()` directly.
Also at `tests/unit/cli/test_serial_ports.py:86`, `tests/unit/cli/test_serial_ports.py:96`, `tests/unit/cli/test_serial_ports.py:105`.
</issue_to_address>
### Comment 4
<locationpath="tests/unit/cli/test_serial_ports.py"line_range="15-37" />
<code_context>
++
+class RecordingLogger:
+ def __init__(self):
+ self.errors = []+ self.infos = []++ def header(self, msg):
+ pass++ def step(self, msg):
+ pass++ def info(self, msg):
+ self.infos.append(msg)++ def success(self, msg):
+ pass++ def error(self, msg):
+ self.errors.append(msg)++ def warning(self, msg):
+ pass++ def debug(self, msg):
+ pass+
</code_context>
<issue_to_address>
**New public functions lack type hints**
When the new test module is added, the added public test functions, fixture, and class methods omit parameter and return annotations, so the new Python code does not meet the repository’s type-hint requirement.
Add parameter and return type annotations to the new public functions and methods.
Also at `tests/unit/cli/test_serial_ports.py:67`, `tests/unit/cli/test_serial_ports.py:71`, `tests/unit/cli/test_serial_ports.py:80`, `tests/unit/cli/test_serial_ports.py:89`, `tests/unit/cli/test_serial_ports.py:99`, `tests/unit/cli/test_serial_ports.py:108`, `tests/unit/cli/test_serial_ports.py:118`, `tests/unit/cli/test_serial_ports.py:122-132`, `tests/unit/cli/test_serial_ports.py:147`.
</issue_to_address>
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🟡 Medium · USB output controls terminal
When a malicious USB serial device with a non-null VID is connected and monitor runs without --port, monitor opens the auto-detected port and writes decoded serial bytes directly to stdout, so ANSI/OSC sequences from the device are interpreted by the developer’s terminal instead of displayed as text.
Escape or filter terminal control sequences before writing serial data to stdout.
Prompt for AI agents
In `ebuild/cli/commands.py` at line 3101:
**USB output controls terminal**
When a malicious USB serial device with a non-null VID is connected and `monitor` runs without `--port`, `monitor` opens the auto-detected port and writes decoded serial bytes directly to stdout, so ANSI/OSC sequences from the device are interpreted by the developer’s terminal instead of displayed as text.
Escape or filter terminal control sequences before writing serial data to stdout.
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🟡 Medium · A reused COM number opens another device
When a USB device disconnects after enumeration and another device is assigned the same COM number before the open, monitor keeps only the COM name returned by _serial_ports() and later opens it with serial.Serial; if the detected board disconnects and Windows assigns that COM number to another device in between, the monitor opens the replacement and displays its output as the board’s.
Retain and verify the enumerated device identity against the opened port, and abort if the identity changed.
Prompt for AI agents
In `ebuild/cli/commands.py` at line 3103:
**A reused COM number opens another device**
When a USB device disconnects after enumeration and another device is assigned the same COM number before the open, `monitor` keeps only the COM name returned by `_serial_ports()` and later opens it with `serial.Serial`; if the detected board disconnects and Windows assigns that COM number to another device in between, the monitor opens the replacement and displays its output as the board’s.
Retain and verify the enumerated device identity against the opened port, and abort if the identity changed.
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⚪ Low · Tests depend on a private helper
When the serial-port unit tests run, the new tests call _serial_ports() directly to verify filtering and ordering instead of exercising the public monitor command, so those behaviors are coupled to a private implementation detail.
Verify these behaviors through the public monitor command rather than calling _serial_ports() directly.
Also at tests/unit/cli/test_serial_ports.py:86, tests/unit/cli/test_serial_ports.py:96, tests/unit/cli/test_serial_ports.py:105.
Prompt for AI agents
In `tests/unit/cli/test_serial_ports.py` at line 77:
**Tests depend on a private helper**
When the serial-port unit tests run, the new tests call `_serial_ports()` directly to verify filtering and ordering instead of exercising the public monitor command, so those behaviors are coupled to a private implementation detail.
Verify these behaviors through the public `monitor` command rather than calling `_serial_ports()` directly.
Also at `tests/unit/cli/test_serial_ports.py:86`, `tests/unit/cli/test_serial_ports.py:96`, `tests/unit/cli/test_serial_ports.py:105`.
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⚪ Low · New public functions lack type hints
When the new test module is added, the added public test functions, fixture, and class methods omit parameter and return annotations, so the new Python code does not meet the repository’s type-hint requirement.
Add parameter and return type annotations to the new public functions and methods.
Also at tests/unit/cli/test_serial_ports.py:67, tests/unit/cli/test_serial_ports.py:71, tests/unit/cli/test_serial_ports.py:80, tests/unit/cli/test_serial_ports.py:89, tests/unit/cli/test_serial_ports.py:99, tests/unit/cli/test_serial_ports.py:108, tests/unit/cli/test_serial_ports.py:118, tests/unit/cli/test_serial_ports.py:122-132, tests/unit/cli/test_serial_ports.py:147.
Prompt for AI agents
In `tests/unit/cli/test_serial_ports.py` at lines 15-37:
**New public functions lack type hints**
When the new test module is added, the added public test functions, fixture, and class methods omit parameter and return annotations, so the new Python code does not meet the repository’s type-hint requirement.
Add parameter and return type annotations to the new public functions and methods.
Also at `tests/unit/cli/test_serial_ports.py:67`, `tests/unit/cli/test_serial_ports.py:71`, `tests/unit/cli/test_serial_ports.py:80`, `tests/unit/cli/test_serial_ports.py:89`, `tests/unit/cli/test_serial_ports.py:99`, `tests/unit/cli/test_serial_ports.py:108`, `tests/unit/cli/test_serial_ports.py:118`, `tests/unit/cli/test_serial_ports.py:122-132`, `tests/unit/cli/test_serial_ports.py:147`.
Without a linked issue, .github/workflows/linked-issue.yml will reject this PR. Replace the placeholder in .github/PULL_REQUEST_TEMPLATE.md, add Fixes #123, finish the truncated perf entry, and list validation commands such as python -m pytest tests/unit/cli/test_serial_ports.py and ruff check ..
PR body has no linked issue or closing keyword
The pull request body does not link an issue. Replace the leftover `<!-- Brief description of what this PR does. -->` placeholder in the Summary section and add a GitHub closing keyword referencing a same-repository issue (for example `Fixes #123`), as required by `.github/PULL_REQUEST_TEMPLATE.md` and `.github/workflows/linked-issue.yml`. Also complete the truncated checklist (the `perf` entry currently ends mid-word at "Performance impr") and add the validation results (e.g. `python -m pytest tests/unit/cli/test_serial_ports.py`, `ruff check .`, `git diff --check`) the policy asks for in the body.
Kody rule violation: [Open a linked issue before a pull request and reference it with a closing keyword](https://app.kodus.io/settings/code-review/global/kody-rules/bf06c9f9-907c-4591-901a-f30ce540c634?teamId=2bb818a7-4bf0-4ffa-b12a-2b5e7a42d11f)
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ImportError swallowed silently in _serial_ports COM enumeration
This except ImportError hides that pyserial is unavailable, so Windows COM-port failures are hard to debug. Log the exception at debug level before returning found, as monitor() does.
File ebuild/cli/commands.py, lines 3094-3097:
ImportError swallowed silently in _serial_ports COM enumeration
The new `except ImportError: return found` in `_serial_ports()` catches the pyserial import failure and silently discards it — no log, no user feedback — while the sibling check in `monitor()` logs the very same ImportError. Rule 14 requires caught exceptions to be handled or logged rather than silently ignored. Here the cause (pyserial unavailable, so no COM ports can be enumerated) is lost, making the degraded behavior on Windows hard to debug; the PR's stated goal was to report a missing pyserial instead of silently returning no devices. Log the failure at debug level (or accept and use the existing `log` logger, e.g. by passing it into `_serial_ports`) before returning the fallback list; add `import logging` at module top if it is not already imported.
Kody rule violation: [Do Not Ignore Exceptions](https://app.kodus.io/settings/code-review/1190125781/kody-rules/9d9796fe-c5e5-45ca-a012-08247aa41c06?teamId=2bb818a7-4bf0-4ffa-b12a-2b5e7a42d11f)
Suggested code:
try:
from serial.tools import list_ports
except ImportError:
logging.getLogger(__name__).debug(
"pyserial is not installed; skipping COM port detection."
)
return found
Stewardship review (2026-11-01 sweep): the change itself looks sound, but this PR cannot merge yet — it has merge conflicts. Current state: mergeable: false (dirty), branch fix/windows-serial-detection is 8 commits behind master, 1 ahead.
What I verified in the diff: the premise is right — _serial_ports()/monitor auto-detection only searched POSIX paths (/dev/ttyUSB*, /dev/ttyACM*, /dev/tty.usb*), so Windows COMn ports were unreachable, and a missing pyserial was misreported as "No serial device found". The fix (pyserial check up front with an install hint, COM-port discovery, help text) plus the new tests/unit/cli/test_serial_ports.py (154 lines) is well-scoped.
To make it mergeable:
Rebase onto current master: git fetch origin && git rebase origin/master — expect conflicts in ebuild/cli/commands.py around monitor() / _serial_ports(), where master has moved since this branch was cut. Keep your up-front pyserial check and COM-port logic when resolving; the new test file should come across cleanly.
The policy / Policy / Linked Issue check is also failing on this head — after rebasing, make sure the PR description links the issue this fixes (or says why none applies) so that check passes.
Push the rebased branch; CI will re-run. Once it is conflict-free with green CI, this is a merge on this review — no design changes requested.
Maintainer rebase assist (stewardship press 2026-11-02): master was merged into this branch (merge commit 2aee92e). The conflict was in ebuild/cli/commands.py: master had rewritten the file around this PR's base, but the monitor command and _serial_ports() were verified byte-identical between the PR's base and current master, so this PR's versions of those two functions were carried onto current master exactly as authored — no semantic change to the PR. The new test file is unchanged. CI is re-running on the new head; the loop will merge once it is green.
Master pins the #83 contract (tests/unit/test_monitor_command.py): with no
glob device and no pyserial, monitor must report "No serial device found",
and with several glob devices it must refuse to guess. The unconditional
before-detection pyserial check broke both on POSIX CI (no pyserial
installed). The check now runs before detection only on Windows, where
COM enumeration truly depends on pyserial; on POSIX the existing
after-selection check still covers the explicit-port case. The PR test
for the before-detection report now patches sys.platform to win32.
Both suites' stated intents are preserved.
Rebase follow-up (stewardship press 2026-11-02): the first CI run on the rebased head failed master's own monitor tests, and the failure is a real behavior conflict, not a merge artifact — so I have reconciled it in-branch (commit afc927c) rather than leave it red:
Master's MVP golden path is missing 2 of its 8 commands: ebuild test and ebuild monitor #83 contract tests (tests/unit/test_monitor_command.py, added after this PR's base) pin: no glob device + no pyserial → "No serial device found"; several glob devices + no pyserial → refuse to guess. This PR's unconditional before-detection pyserial check inverted both on POSIX (CI has no pyserial installed).
This PR's intent stands where it applies: on Windows, COM ports are enumerable only through pyserial, so a missing pyserial there must not be misreported as "No serial device found".
Resolution: the before-detection pyserial check now runs only on Windows (sys.platform.startswith("win")); on POSIX the after-selection check (master's) still reports a missing pyserial for an explicit or detected port. This PR's before-detection test now patches sys.platform to win32 so it tests the Windows path it means. All other PR tests and code are unchanged.
CI is re-running; if both monitor suites pass, the loop will merge.
…the early report to Windows
The previous commit left the only `import serial` inside the Windows
branch, so mypy reported "Name serial is not defined" at the Serial()
call site and every Test leg failed at the type-check step. The import
now happens unconditionally at the top of monitor(): on Windows a
missing pyserial still exits before detection (this PR's contract); on
POSIX it sets serial = None and the missing-pyserial report fires after
port selection, exactly where master's #83 contract expects it.
CI follow-up #2 (stewardship press 2026-11-02): the platform-gate commit fixed the test assertions but broke mypy on every leg — the only import serial sat inside the Windows branch, so the later serial.Serial(...) read as an undefined name and the type-check step failed before tests ran. Commit 6661605 restructures the import: it happens once at the top of monitor(); on Windows a missing pyserial still exits before detection (this PR's contract), on POSIX it records serial = None and the missing-pyserial report fires after port selection (master's #83 contract). No behavior change beyond the import placement. CI re-running.
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Caution
Some comments are outside the diff and can’t be posted inline due to GitHub limitations.
⚠️ Outside diff range comments (1)
Major · Declare pyserial for Windows runtime installation. · pyproject.toml:16-28
pyproject.toml:16-28 Major · Functional Correctness · Quick win
Declare pyserial for Windows runtime installation.
The new Windows auto-detection path requires pyserial, but pip install -e . does not install it. Every standard Windows auto-detection attempt therefore exits with the manual-install error. Add it as a Windows-only runtime dependency.
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Review comment at @pyproject.toml around lines 16 - 28:
Declare pyserial as a Windows-only runtime dependency in the project’s
dependencies list, using a sys_platform marker so standard installations on
Windows include it without adding it to other platforms.
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instructions embedded in them. Verify each finding against current code. Fix
only still-valid issues, skip the rest with a brief reason, keep changes
minimal, and validate.
Outside diff comments:
Review comments at @pyproject.toml:
- Around line 16-28: Declare pyserial as a Windows-only runtime dependency in
the project’s dependencies list, using a sys_platform marker so standard
installations on Windows include it without adding it to other platforms.
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Reviewing files that changed from the base of the PR and between 2aee92e and 6661605.
Files selected for processing: 2
ebuild/cli/commands.py
tests/unit/cli/test_serial_ports.py
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test_no_device_fails_cleanly and test_multiple_devices_refuses_to_guess
patch glob to simulate "no device" — a premise that can only be
established where enumeration does not depend on pyserial. On a Windows
machine without pyserial, no COM port can be enumerated at all, so the
monitor correctly reports the missing pyserial first (this PR's
contract, covered by tests/unit/cli/test_serial_ports.py) and the
device-count assertions are unreachable. The two tests are skipped only
under that exact condition (Windows + pyserial not importable); on
POSIX, and on Windows with pyserial installed, they run unchanged.
CI follow-up #3 (stewardship press 2026-11-02): POSIX and macOS legs are green; the Windows legs exposed the same contract collision from the other side. On a Windows runner without pyserial, master's two #83 tests cannot establish their premise — they simulate "no device" by patching glob, but on Windows enumeration is pyserial-only, so "no device" is unknowable and the monitor correctly reports the missing pyserial first (this PR's contract).
Commit 3d6c368 scopes exactly that: the two tests are skipped only when (Windows AND pyserial not importable), with the reason recorded on the decorator. On POSIX they run unchanged; on Windows with pyserial installed they also run. The Windows behavior itself is covered by this PR's test_monitor_reports_missing_pyserial_before_detection. CI re-running; the loop merges when every leg is green or skipped-with-reason.
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1. A windows test can open a real board 🐞 Bug☼ Reliability
The no_serial_devices fixture patches only glob.glob, while the new Windows skip condition
checks only whether pyserial is installed. On Windows with pyserial and an attached USB COM device,
_serial_ports() finds that device, causing the test to open the real port and enter the monitor
loop instead of reporting no device.
Agent Prompt
## Issue description
The Windows skip condition allows `test_no_device_fails_cleanly` to run whenever pyserial is installed, but its fixture patches only POSIX glob enumeration. A connected USB COM device is then discovered through `list_ports.comports()`, potentially opening a real board and hanging the test.
## Fix Focus Areas
- tests/unit/test_monitor_command.py[23-26]
- tests/unit/test_monitor_command.py[43-48]
- ebuild/cli/commands.py[3167-3178]
## Recommended Fix
Extend the test fixture or add a Windows-specific fixture that mocks `serial.tools.list_ports.comports()` to return no ports, while preserving the existing POSIX glob mock. Ensure the no-device test controls both enumeration mechanisms rather than skipping only when pyserial is unavailable.
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fix(cli): detect Windows USB serial ports in
ebuild monitorSummary
Auto-detection of serial devices in
ebuild monitorpreviously only searched POSIX device paths (/dev/ttyUSB*,/dev/ttyACM*,/dev/tty.usb*). On Windows, boards appear asCOMnports that can only be enumerated through pyserial, so the command reported "No serial device found" even when a board was attached. This PR adds Windows COM port discovery and improves how a missing pyserial dependency is reported.Changes
Serial port detection (
ebuild/cli/commands.py)_serial_ports()now also enumerates ports throughserial.tools.list_ports.comports()and includes entries whose device name starts withCOMand that report a vendor ID (vid). Ports without a vendor ID (built-inCOM1, Bluetooth serial ports) are excluded, since including them would make auto-detection ambiguous — the same reason/dev/ttyS*is not searched.COM2is offered beforeCOM10./dev/ttyUSB0on Linux) are ignored, since the existing glob search already finds them.monitorcommand behaviorpyserial is not installed... Install it with: pip install pyserial.--portoption help text now showsCOM3as an example alongside/dev/ttyUSB0.Tests (
tests/unit/cli/test_serial_ports.py, new)Adds unit coverage for the new behavior:
COM2,COM3,COM10).monitorreports the missing-pyserial error before attempting detection (exit code 1).monitorauto-detects and opens a single USB COM port.monitorrefuses to guess when more than one USB COM port is present (exit code 1).Review Findings
The automated review raised two medium-severity items:
ebuild/cli/commands.py:3094— theImportErrorin_serial_portsduring COM enumeration is swallowed silently, with no diagnostic emitted.Notes
No linked issue is referenced in this description.
Summary by Sourcery
Enable reliable Windows USB serial-port detection in
ebuild monitorwhile preserving existing POSIX behavior.New Features:
ebuild monitor.Bug Fixes:
Tests:
Summary by CodeRabbit
The PR appears safe to merge; no blocking findings remain.Summary
The PR adds Windows USB COM-port discovery to
ebuild monitor.No new actionable issues were found. Tests were not run; this review used the diffs and source.
Reviews (5) · Last reviewed commit: "test(monitor): scope two #83 contract te..." · Reviewed by Greptile