Treat 204 No Content as no rows; require morpc 0.7.5 (v0.6.5)

[jinskeep-morpc]

Problem

The Census API returns 204 No Content when a request is valid but it has no data for the requested geographies. ACS 5-year 2017 lists place/remainder parts (070) in its geography list, but returns 204 for every 070 request, in both ucgid and for/in forms; other years and levels are fine. Since morpc 0.7.3 that raised HTTPError, which stopped the whole CensusAPI fetch and the morpc-pop-collect notebook run.

Change

• CensusAPI._fetch_variables catches an HTTPError whose response.status_code is 204, logs a warning, and treats that request as zero rows. If every request is empty, CensusAPI.long is an empty frame. Other HTTP errors still raise.
• Requires morpc ≥ 0.7.5:
  • 0.7.4 attaches the response to HTTPError, which this fix relies on.
  • 0.7.5 redacts API keys from morpc.req logs and errors (Redact API keys and tokens from morpc.req logs and errors morpc-py#207), completing the logging fix in Stop logging the Census API key in geoinfo_from_params #8.
• CHANGELOG entries for 0.6.5 (Stop logging the Census API key in geoinfo_from_params #8 and this PR), and a reference/dev_notes.md entry.

Testing

• 3 new tests in tests/test_api.py: a 204 chunk is skipped while the others are kept; an all-204 fetch returns an empty frame with the expected columns; a 400 still raises. The two 204 tests failed before the change.
• Full suite: 347 passed.
• Live: CensusAPI(Endpoint('acs/acs5', 2017), 'region15', sumlevel=SumLevel('070'), ...) returns an empty long with warnings, instead of RuntimeError.

🤖 Generated with Claude Code