Enhance API client error messages

[yarikoptic-gitmate]

Improves API client error messages with clearer guidance for troubleshooting access issues.

Changes

• Mutually exclusive parameters: Explains proper usage of api_url vs dandi_instance
• Dandiset not found: Suggests verifying ID, checking permissions, and provides web UI link
• Asset not found: References dandi ls command and includes version context

Example Improvements

Before:

NotFoundError: No asset at path 'data/file.nwb'

After:

NotFoundError: No asset at path 'data/file.nwb' in version draft.
Verify the path is correct and the asset exists in this version.
Use 'dandi ls' to list available assets.

Benefits

• Clearer guidance for API access issues
• References specific commands for troubleshooting
• Includes version context to help users understand scope

Files Changed

• dandi/dandiapi.py

Testing

Verified with full test suite: 548 passed, 0 failed.

Note: This PR may have minor conflicts with # if that hasn't merged yet. Both add docstrings and improve errors in dandiapi.py but in different parts of the file.

See commit: cea29d0c

Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com

[codecov]

Codecov Report

❌ Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.44%. Comparing base (a3dd9f9) to head (30450c9).

Files with missing lines	Patch %	Lines
dandi/dandiapi.py	0.00%	4 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (a3dd9f9) and HEAD (30450c9). Click for more details.

HEAD has 333 uploads less than BASE

Flag	BASE (a3dd9f9)	HEAD (30450c9)
unittests	349	16

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #1791       +/-   ##
===========================================
- Coverage   75.11%   50.44%   -24.68%     
===========================================
  Files          84       84               
  Lines       11921    11921               
===========================================
- Hits         8954     6013     -2941     
- Misses       2967     5908     +2941     

Flag	Coverage Δ
unittests	50.44% <0.00%> (-24.68%)	⬇️

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