fix(ci_visibility): don't rely on git in pytest plugin [backport 2.8]

[romainkomorndatadog]

Backport c460441 from #9989 to 2.8.

Fixes an issue introduced by #9586 and reported in #9981 where the pytest plugin would crash if the git binary was absent.

The workspace is instead grabbed from the CIVisibility service's tags (via a new getter classmethod).

In order for the variable to persist through to the pytest_terminal_summary hook, it is moved from being stashed on the pytest session object to the nested config object (which itself is passed to pytest_terminal_summary).

For improved testability, a function to get the location of the git binary's passed, using @cached() to avoid re-fetching the path each time we call git.

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: backport-9989-to-2.8
Commit report: 57598d4
Test service: dd-trace-py

❌ 11 Failed (1 Known Flaky), 169635 Passed, 1487 Skipped, 12h 37m 36.79s Total duration (28m 3.06s time saved)
❄️ 1 New Flaky
⌛ 2 Performance Regressions

❌ Failed Tests (11)

This report shows up to 5 failed tests.

• test_get_distributions - test_packages.py - ❄️ Known flaky - Details

  Expand for error

   assert {'attrs', 'au...overage', ...} == {'attrs', 'au...overage', ...}
     Extra items in the left set:
     'importlib-resources'
     Extra items in the right set:
     'importlib_resources'
     Full diff:
       {
        'attrs',
        'autocommand',
        'backports.tarfile',
   ...
  

• test_span_creation_and_finished_metrics_otel - test_telemetry_metrics_e2e.py - Details

  Expand for error

   b'Failed to load context: ddcontextvars_context, fallback to contextvars_context
     Traceback (most recent call last):
     ... return tracer_provider.get_tracer(
     TypeError: get_tracer() takes from 2 to 4 positional arguments but 5 were given
     '
   assert 1 == 0
  

• test_span_creation_and_finished_metrics_otel - test_telemetry_metrics_e2e.py - Details

  Expand for error

   b'Failed to load context: ddcontextvars_context, fallback to contextvars_context
     Traceback (most recent call last):
     ...^^^^^^^^^^^^^^^^^^^^
     TypeError: TracerProvider.get_tracer() takes from 2 to 4 positional arguments but 5 were given
     '
   assert 1 == 0
  

• test_span_creation_and_finished_metrics_otel - test_telemetry_metrics_e2e.py - Details

  Expand for error

   b'Failed to load context: ddcontextvars_context, fallback to contextvars_context
     Traceback (most recent call last):
     ... return tracer_provider.get_tracer(
     TypeError: get_tracer() takes from 2 to 4 positional arguments but 5 were given
     '
   assert 1 == 0
  

• test_span_creation_and_finished_metrics_otel - test_telemetry_metrics_e2e.py - Details

  Expand for error

   b'Failed to load context: ddcontextvars_context, fallback to contextvars_context
     Traceback (most recent call last):
     ...^^^^^^^^^^^^^^^^^^^^
     TypeError: TracerProvider.get_tracer() takes from 2 to 4 positional arguments but 5 were given
     '
   assert 1 == 0
  

New Flaky Tests (1)

• test_send_timed_events - test_llmobs_writer.py - Last Failure

  Expand for error

   Calls not found.
   Expected: [call('sent %d LLMObs events to %r', 1, 'https://llmobs-intake.datad0g.com/api/v2/llmobs')]
  

⌛ Performance Regressions vs Default Branch (2)

• test_schematized_operation_names[None] - test_djangorestframework.py 6.98s (+5.66s, +426%) - Details
• test_schematized_service_name[None-None] - test_request.py 6.49s (+5.53s, +579%) - Details

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-08-02 07:44:06

Comparing candidate commit 161b56f in PR branch backport-9989-to-2.8 with baseline commit 3f5a7c5 in branch 2.8.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 201 metrics, 9 unstable metrics.