fix: remove VectorData unit generation patch

[ehennestad]

Motivation

NWB schema 2.10 introduces types.core.TimestampVectorData.unit (and types.core.DurationVectorData.unit) with fixed value seconds. MatNWB currently injects a hidden unit = "volts" property onto the types.hdmf_common.VectorData class as an older Units-table compatibility patch.

The current type generation pipeline now generates an invalid TimestampVectorData class definition under NWB schema 2.10.0, because a property (unit in this case) can not be defined on both a subclass (TimestampVectorData) and a superclass (VectorData).

This PR fixes that by removing the hidden units property from the VectorData class.

What changed

• Removed units property compatibility patch when generating VectorData class
• Removed the generated Units compatibility backfill that copied nested VectorData.unit values into promoted *_unit properties, e.g. obj.waveforms.unit into obj.waveforms_unit

Additional details

The Units-table compatibility patch creates unit, sampling_rate and resolution as hidden properties on the VectorData class in order to assign those properties to VectorData for the waveform_mean, waveform_sd, waveforms columns of a Units table.

This PR removes only the global VectorData.unit patch. Units-table waveform unit attributes are already handled by the schema-driven promoted-container API recently added in #797 (waveform_mean_unit, waveform_sd_unit, and waveforms_unit), so MatNWB no longer needs to leak unit onto all VectorData subclasses.

We could also remove the compatibility patch for sampling_rate and resolution in this PR, but that would risk breaking existing scripts/conversion code that depends on the legacy syntax. Removing only the unit patch is safer, because this was already a read-only property, whereas sampling_rate and resolution are also settable via the API.

This PR also removes the generated Units compatibility backfill that copied nested VectorData.unit values into promoted *_unit properties, e.g. obj.waveforms.unit into obj.waveforms_unit. That backfill was introduced in #797 to preserve the old nested syntax, but it depends on the same global VectorData.unit patch removed here. The promoted *_unit properties remain generated and exported directly from the containing Units object.

How to test the behavior?

runtests('tests.unit.file.VectorDataPatchTest')

Checklist

• Have you ensured the PR description clearly describes the problem and solutions?
• Have you checked to ensure that there aren't other open or previously closed Pull Requests for the same change?
• If this PR fixes an issue, is the first line of the PR description fix #XX where XX is the issue number?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.41%. Comparing base (3e8407b) to head (1e2fbbc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #823      +/-   ##
==========================================
- Coverage   95.42%   95.41%   -0.01%     
==========================================
  Files         215      215              
  Lines        7648     7632      -16     
==========================================
- Hits         7298     7282      -16     
  Misses        350      350              

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[Copilot]

Pull request overview

Removes MatNWB’s legacy, schema-injecting VectorData.unit compatibility patch to prevent property redefinition conflicts in NWB schema 2.10+ (e.g., TimestampVectorData.unit), while relying on the schema-driven promoted Units.*_unit API introduced in #797.

Changes:

• Removed the hidden read-only unit="volts" injection from types.hdmf_common.VectorData (constructor parsing and export-conditional attribute write).
• Removed generator-side VectorData.unit patching and related export/hidden-property special-casing.
• Added a unit test asserting VectorData no longer has unit, while sampling_rate/resolution remain and Units exposes waveform_*_unit promoted properties.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
+types/+hdmf_common/VectorData.m	Drops the generated hidden unit property and stops writing /unit on export.
+tests/+unit/+file/VectorDataPatchTest.m	Adds coverage ensuring unit is not injected into VectorData and promoted Units unit properties exist.
+file/processClass.m	Removes the generator patch that injected the unit attribute into VectorData.
+file/fillExport.m	Removes VectorData-specific unit export conditional generation.
+file/fillClass.m	Stops treating unit as a special hidden VectorData property during class generation.
+file/+internal/isPropertyHidden.m	Stops hiding unit for VectorData in generator internals.

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[ehennestad]

@bendichter

Just realised that TimestampVectorData and DurationVectorData also defines the resolution attribute.
In my opinion, the simplest fix is to remove the add-hoc VectorData patch entirely, as it was already made redundant in PR #797

The drawback is that existing(?) code relying on setting the resolution of VectorData objects that go into the waveform* columns of a Units table will break, and it is not straight-forward to add a specific error message for such breakage.

The property was already hidden and the syntax was not described in any tutorials, so I expect the number of affected users would be very small.

Would appreciate your input!