[anikeya9]

Closes #2443.

OptimadeClient._build_url put the query parameter values into the URL as they are, so +, & and # in a filter kept their URL meaning (space, parameter separator, fragment) and the server received a different filter. The spec asks the client to URL-encode the filter parameter ("URL Encoding"; "Filtering": "the contents of the filter parameter is URL-encoded by the client").

Changes

• _build_url percent-encodes the values of filter, response_fields, sort and other_params with urllib.parse.quote(..., safe=","). Commas are kept, as they separate list values (response_fields=id,elements). The next links from the servers are not changed.
• New tests in tests/server/test_client.py:
  • test_client_url_encoding: _build_url with chemical_formula_descriptive = "A+B&C#D" and a + response field decodes back (parse_qs) to exactly the same values;
  • test_client_awkward_nested_provider_field (sync and async): filters on _exmpl_stability.gga_gga+u_r2scan < 0 through the client against the test server and expects mpf_3819, the same field and result as the server test test_awkward_nested_provider_field added in Use 1.2 grammar by default and relax rules on nested fields #2242 (which sends %2B by hand). Without the encoding the server answers 400. Marked xfail on Elasticsearch, like the server test, since that backend does not support nested provider fields.

Tests

• pytest tests/server/test_client.py: 140 passed; both new tests fail without the change.
• CI: the pre-commit.ci failure is unrelated: its runner image has no python3.10, which default_language_version pins ("failed to find interpreter for Builtin discover of python_spec='python3.10'"); the same hooks pass in the GitHub Actions pre-commit job.
• pre-commit run on the two files: all hooks pass.
• Against Materials Project, the nested fields from Unable to create filters with "+" in nested property name #2182 can now be queried with the client:

  OptimadeClient(base_urls=["https://optimade.materialsproject.org"]).count(
      "_mp_stability.gga_gga+u.energy_above_hull < 0.1"
  )
  # before: 400 "Unable to parse filter _mp_stability.gga_gga u.energy_above_hull < 0.1"
  # after:  104259

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.21%. Comparing base (ecb4b60) to head (c174b48).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2444   +/-   ##
=======================================
  Coverage   90.21%   90.21%           
=======================================
  Files          78       78           
  Lines        5037     5039    +2     
=======================================
+ Hits         4544     4546    +2     
  Misses        493      493           

Flag	Coverage Δ
project	90.21% <100.00%> (+<0.01%)	⬆️
validator	90.21% <100.00%> (+<0.01%)	⬆️

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[ml-evs]

This looks useful, thanks @anikeya9 !