Fix aggregate reading a TestRun attribute that does not exist

[serhiy-bzhezytskyy]

Description

update_config_object read test_run.cluster_config_instance_params, which no test run has, so aggregate failed on every invocation:

[ERROR] ❌ Cannot aggregate. 'TestRun' object has no attribute 'cluster_config_instance_params'.

TestRun defines cluster_config_params (osbenchmark/metrics.py:1343), and the name being read occurs nowhere else in the repository — nothing assigns it. #882 (2c85d505) renamed the attribute on TestRun to cluster_config_params but renamed this read site to cluster_config_instance_params; #939 (e10342d1) later corrected the config key on that same line, from cluster_config_instance.params to cluster_config.params, and left the attribute name as it was. This one-word change reads the name TestRun actually defines.

Unlike the null-metrics crash (#1093), this does not depend on the data — it is on the plain aggregate → build_aggregated_results → update_config_object path. As far as I can tell it means aggregate cannot currently succeed for anyone on main.

A side effect of the fix: because the read never succeeded, the cluster-config params never reached the aggregated result. They now do.

Issues Resolved

Resolves #1094

Testing

• New functionality includes testing

• One new test, test_update_config_object_reads_attributes_that_test_runs_actually_have, which constructs a real metrics.TestRun and asserts the cluster_config.params value reaches config.add.

• Verified red without the fix: with main's aggregator.py restored under the new test it fails with AttributeError: 'TestRun' object has no attribute 'cluster_config_instance_params'; with the fix it passes.

• Full suite: 1423 passed, 5 skipped (baseline on main is 1422). pylint clean.

• End-to-end through the real CLI: aggregate reports ✅ SUCCESS and the aggregated result now carries cluster-config-instance-params: {'heap_size': '6g'}, which was being silently lost.

The reason the existing suite doesn't catch this is worth flagging on its own: tests/aggregator_test.py never constructs a real TestRun — every test passes a bare Mock(), and a Mock returns a fresh Mock for any attribute name asked of it, so a wrong name reads fine. main sits at 1422 passed while aggregate cannot complete once. Mock(spec=TestRun) does not fix it either, because spec inspects the class, which knows nothing about attributes assigned in __init__; it raises on cluster_config first and points at the wrong line. A real TestRun is the only thing that catches it, which is why the new test builds one.

Notes

Found while using Apache solr-orbit, a Python port of OSB whose aggregator.py is byte-identical to this one apart from the import module name, to run a multi-configuration benchmark campaign. The same fix is proposed there as apache/solr-orbit#59.

This was the second of three defects blocking aggregate; it only became visible after the null-metrics crash was fixed, because that one happens earlier on the same path.

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[OVI3D0]

LGTM, thanks @serhiy-bzhezytskyy !