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fix: handle i2c device permissions errors gracefully #409

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fix: handle i2c device permissions errors gracefully #409

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6c62c8e
Fix exiting immediately on i2c permissions error
danudey Oct 17, 2025
07c96a3
Merge branch 'main' into fix-missing-permissions-errors
danudey Oct 21, 2025
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10 changes: 9 additions & 1 deletion monitorcontrol/vcp/vcp_linux.py
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Original file line number Diff line number Diff line change
Expand Up @@ -390,12 +390,20 @@ def get_vcps() -> List[LinuxVCP]:

# iterate I2C devices
for device in pyudev.Context().list_devices(subsystem="i2c"):
vcp = LinuxVCP(device.sys_number)
try:
if sys_no := device.sys_number:
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@newAM newAM Nov 23, 2025

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Suggested change
if sys_no := device.sys_number:
if (sys_no := device.sys_number) is None:

I think 0 is a valid device.sys_number.

vcp = LinuxVCP(int(sys_no))
else:
logging.error(
"Unable to check i2c device %s: no device number found", device
)
continue
Comment on lines +396 to +400
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@newAM newAM Nov 23, 2025

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I am curious, have you seen this occur? pyudev should only return None if the device number is not a unicode string: https://github.com/pyudev/pyudev/blob/7588bc8c84bf1e994b31020452124bc6618625ce/src/pyudev/device/_device.py#L626-L651

with vcp:
pass
except (OSError, VCPIOError):
pass
except VCPPermissionError as exc:
logging.error("Unable to check i2c device: %s", exc)
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@newAM newAM Nov 23, 2025

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Suggested change
logging.error("Unable to check i2c device: %s", exc)
logging.exception("Unable to check i2c device")

This adds native exception info into the logging record.

else:
vcps.append(vcp)

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