CNDB-15526: Load TOC component before performing component discovery

[driftx]

What is the issue

TOCComponent performs component discovery before loading the TOC. This can be detrimental to custom component loading and can be optimized to try loading the TOC directly first before resorting to discovery.

What does this PR fix and why was it fixed

Load the TOC component without discovery if possible

[github-actions]

Checklist before you submit for review

• This PR adheres to the Definition of Done
• Make sure there is a PR in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits
• All new files should contain the DataStax copyright header instead of the Apache License one

[sonarqubecloud]

Quality Gate failed

Failed conditions
50.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-2028 rejected by Butler

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7 regressions found
See build details here

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Found 7 new test failures

Test	Explanation	Runs	Upstream
replica_side_filtering_test.TestAllowFiltering.test_update_on_collection (offheap-bti)	<span title="The test is NOT RUN on upstream but FLAKY on feature:
• Feature branch: FLAKY because there are 1 passing, 1 failing, 0 missing, and 0 skipped runs in the last 2 runs in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔵🔴	0 / 8
replica_side_filtering_test.TestAllowFiltering.test_update_on_wide_table (offheap-bti)	<span title="The test is NOT RUN on upstream but FLAKY on feature:
• Feature branch: FLAKY because there are 1 passing, 1 failing, 0 missing, and 0 skipped runs in the last 2 runs in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔵🔴	0 / 8
o.a.c.cql3.validation.operations.AggregationQueriesTest.testAggregationQueryShouldNotTimeoutWhenItExceedesReadTimeout (compression)	<span title="The test is NOT RUN on upstream but FAILING on feature:
• Feature branch: FAILING in the recent 2 >= 2 minimum runs (2 actual failures, 0 missing/skipped) in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔴🔴	2 / 8
o.a.c.db.ColumnFamilyStoreTest.testSnapshotCreationAndDeleteEmptyTable ()	<span title="The test is NOT RUN on upstream but FAILING on feature:
• Feature branch: FAILING in the recent 2 >= 2 minimum runs (1 actual failures, 1 missing/skipped) in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔴⚪	1 / 8
o.a.c.db.compaction.unified.ShardedMultiWriterTest.testShardedCompactionWriter_threeShard[isReplicaAware=true] (compression)	<span title="The test is NOT RUN on upstream but FLAKY on feature:
• Feature branch: FLAKY because there are 1 passing, 1 failing, 0 missing, and 0 skipped runs in the last 2 runs in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔴🔵	0 / 8
o.a.c.index.SecondaryIndexManagerTest.testIndexRebuildWhenAddingSStableViaRemoteReload (compression)	<span title="The test is NOT RUN on upstream but FAILING on feature:
• Feature branch: FAILING in the recent 2 >= 2 minimum runs (2 actual failures, 0 missing/skipped) in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔴🔴	7 / 8
o.a.c.index.sai.cql.datamodels.QueryWriteLifecycleWithCompositePartitionKeyTest.testWriteLifecycle[ca] ()	<span title="The test is NOT RUN on upstream but FAILING on feature:
• Feature branch: FAILING in the recent 2 >= 2 minimum runs (1 actual failures, 1 missing/skipped) in 4 builds (1 to 5)
• Upstream branch: MISSING in the last run in 8 builds (147 to 154)">NEW	🔴⚪	0 / 8

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Found 3 known test failures

[djatnieks]

Left a question

[djatnieks]

This check is not needed?

[driftx]

From what I can tell it's an optimization to return early. The exists() triggers an opening of the file though and that is what causes issues.