agents/sysfsgpio: fix misleading Python error when permission denied #1704
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
If the executor doesn't have the proper permissions to control the GPIO or export it, a Permission Denied will be raised. However, __del__ is called regardless and gpio_sysfs_value_fd attribute isn't present if the __init__ doesn't finish. Thus, Python prints the following: """ Exception ignored in: <function GpioDigitalOutput.__del__ at 0x7f5b017f80e0> Traceback (most recent call last): File "<loaded sysfsgpio>", line 44, in __del__ AttributeError: 'GpioDigitalOutput' object has no attribute 'gpio_sysfs_value_fd' """ before the raised Exception, possibly misleading the user on their debugging quest. Therefore, let's make sure the attribute exists before anything can throw an Exception in __init__. os.close() can only be called on a valid file descriptor, which None isn't, therefore only call os.close() if self.gpio_sysfs_value_fd is not None. Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #1704 +/- ##
======================================
Coverage 55.6% 55.6%
======================================
Files 172 172
Lines 13471 13473 +2
======================================
+ Hits 7500 7502 +2
Misses 5971 5971
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. |
sjg20
approved these changes
Jul 23, 2025
Emantor
approved these changes
Jul 26, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
If the executor doesn't have the proper permissions to control the GPIO or export it, a Permission Denied will be raised. However, del is called regardless and gpio_sysfs_value_fd attribute isn't present if the init doesn't finish.
Thus, Python prints the following:
"""
Exception ignored in: <function GpioDigitalOutput.del at 0x7f5b017f80e0>
Traceback (most recent call last):
File "", line 44, in del
AttributeError: 'GpioDigitalOutput' object has no attribute 'gpio_sysfs_value_fd'
""" before the raised Exception, possibly misleading the user on their debugging quest.
Therefore, let's make sure the attribute exists before anything can throw an Exception in init.
os.close() can only be called on a valid file descriptor, which None isn't, therefore only call os.close() if self.gpio_sysfs_value_fd is not None.
This has been tested by running labgrid with a non-root user with the GPIO not exported and the non-root user not having permission to write to
/sys/class/gpio/export.Checklist