Fix TypeError when channel/acquisition metadata contains None values#169
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cbrnr merged 2 commits intoxdf-modules:mainfrom Mar 31, 2026
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When an XDF file has channel or acquisition metadata fields present but
with null values, playback_lsl.py would crash with:
TypeError: descriptor 'encode' for 'str' objects doesn't apply to a 'NoneType' object
because pylsl's append_child_value calls str.encode() on the value.
Add a None-check before each append_child_value call, and wrap the value
in str() so that non-string scalars (e.g. numeric precision fields) are
also handled safely.
Contributor
Author
|
cc @cbrnr |
Contributor
|
Thanks! LGTM! Can you add a changelog entry please? |
Contributor
|
Thanks @sappelhoff! |
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Disclaimer: I created this PR and the content using Claude.
Summary
playback_lsl.pycrashes with aTypeErrorwhen an XDF file contains channel or acquisition metadata fields that are present but haveNonevalues:This happens in
pylsl'sappend_child_value, which callsstr.encode()on the value passed to it.Fix
None(guard added to both theacquisitionandchannelloops)str()so non-string scalars (e.g. a numericprecisionfield) are also handled correctlyTest plan
Nonechannel metadata (e.g. a missingunitfield) — previously crashed, now streams successfully