fix: address CodeQL control-flow and API warnings

[FrankChen021]

What changed

• Correct nonterminating/constant control flow, comparator contracts, iterator reuse, and redundant tests.
• Make affected enum switches explicit in production code, tests, and the tracked SQL parser template.
• Replace ad-hoc test implementations with existing contract-correct row and iterator types.
• Document 21 intentional identity, ordering, optional-operation, and dual-evaluation contracts with narrow CodeQL suppressions.

Why

The current CodeQL snapshot reports 63 control-flow and API-contract warnings across 13 queries. This change addresses 61 of them:

• 40 direct code or contract fixes
• 21 precise suppressions for intentional semantics

The remaining two java/subtle-inherited-call alerts are in untracked output from protoc-gen-grpc-java. The current official gRPC Java generator still emits the same pattern. Editing target/ would not be durable, and excluding the query repository-wide would weaken future scanning, so those two generator-owned findings are intentionally not hidden by this PR.

Impact

The main behavioral fix prevents ByteBufferMinMaxOffsetHeap.siftDown from looping when no grandchild swap is needed. Comparator and iterator test helpers now satisfy their API contracts, enum evolution is handled explicitly, and SQL parser regeneration preserves the fixes.

Root cause

Some implementations intentionally use identity or partial ordering semantics that CodeQL cannot infer. Other findings were genuine missing enum cases, one-shot iterator wrappers, constant assertions, or incomplete comparison contracts. Six alerts originated in generated code; four map to the repository-owned SQL parser template and are fixed there, while two originate entirely in the external gRPC generator.

Checks

• 11,919 focused test executions passed
• 2 tests skipped
• Processing compile and checkstyle passed
• SQL parser regeneration and compilation passed
• Focused multi-module reactors passed
• git diff --check

Created by GPT-5.6-Sol.

[Copilot]

Pull request overview

This PR reduces CodeQL control-flow and API/contract findings across Druid by fixing a few real logic issues (notably a potential non-terminating heap sift) and by making intentional semantics explicit via narrow suppressions and clearer enum-switch handling. It touches core processing code, MSQ/controller paths, indexing metadata types, and a number of tests/utilities to align comparators/iterators with their contracts.

Changes:

• Fix/control-flow and contract issues (e.g., ByteBufferMinMaxOffsetHeap.siftDown termination; comparator/iterator contract correctness in test helpers; remove redundant/constant assertions/tests).
• Make enum switches explicit for newer ARRAY/COMPLEX cases and document intentional identity/ordering semantics with CodeQL suppressions.
• Replace ad-hoc test rows/iterators with existing concrete implementations and add focused equality/hashCode coverage where needed.

Reviewed changes

Copilot reviewed 45 out of 45 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
sql/src/main/codegen/templates/Parser.jj	Adds explicit switch fall-through handling in the tracked SQL parser template to satisfy enum-switch expectations.
server/src/test/java/org/apache/druid/server/coordinator/simulate/WrappingScheduledExecutorService.java	Fixes ScheduledFuture comparator contract in a test utility by adding stable ordering and identity equality.
server/src/test/java/org/apache/druid/server/coordinator/duty/CompactSegmentsTest.java	Removes redundant constant assertions and aligns with final style.
server/src/test/java/org/apache/druid/segment/realtime/sink/SinkTest.java	Replaces ad-hoc InputRow implementations with MapBasedInputRow for contract-correct test inputs.
server/src/test/java/org/apache/druid/rpc/NoDelayScheduledExecutorService.java	Fixes ScheduledFuture comparator contract in a test utility by adding stable ordering and identity equality.
server/src/main/java/org/apache/druid/server/QueryResultPusher.java	Handles additional error categories explicitly in the exception-to-counter mapping switch.
server/src/main/java/org/apache/druid/metadata/BasicDataSourceExt.java	Documents and suppresses an intentional test-only accessor that can’t override a package-private superclass getter.
processing/src/test/java/org/apache/druid/timeline/partition/HashBasedNumberedShardSpecTest.java	Makes HashInputRow equality/comparison contract-correct for tests.
processing/src/test/java/org/apache/druid/segment/transform/TransformerTest.java	Replaces ad-hoc InputRow with MapBasedInputRow for correct row behavior in tests.
processing/src/test/java/org/apache/druid/segment/transform/RowFunctionTest.java	Simplifies test setup using MapBasedRow and stable timestamps.
processing/src/test/java/org/apache/druid/segment/data/VSizeColumnarIntsTest.java	Adds explicit equals/hashCode tests for VSizeColumnarInts.
processing/src/test/java/org/apache/druid/segment/column/TypeStrategiesTest.java	Fixes Comparable contract behavior in a test helper type and removes obsolete primitives usage.
processing/src/test/java/org/apache/druid/query/search/SearchQueryRunnerTest.java	Removes a redundant type assertion in a search query test.
processing/src/test/java/org/apache/druid/query/scan/ScanQueryRunnerTest.java	Removes a logically redundant bounds check in a test loop.
processing/src/test/java/org/apache/druid/math/expr/VectorExprResultConsistencyTest.java	Makes vector binding population explicitly reject unsupported types with a clear exception.
processing/src/test/java/org/apache/druid/java/util/common/guava/ConcatSequenceTest.java	Fixes iterator reuse to ensure each iterator() call returns a fresh iterator as required.
processing/src/test/java/org/apache/druid/collections/IntSetTestUtility.java	Removes a custom iterator wrapper and iterates IntIterator directly to satisfy iterator contracts.
processing/src/main/java/org/apache/druid/segment/incremental/SpatialDimensionRowTransformer.java	Documents and suppresses intentional identity/ordering semantics in an InputRow wrapper.
processing/src/main/java/org/apache/druid/segment/filter/ExpressionFilter.java	Makes array-element-type switch explicit for ARRAY/COMPLEX element types.
processing/src/main/java/org/apache/druid/segment/data/VSizeColumnarInts.java	Implements value-based equals/hashCode consistent with compareTo.
processing/src/main/java/org/apache/druid/segment/data/CompressedBlockReader.java	Removes a redundant assert in block-size validation while retaining state checks.
processing/src/main/java/org/apache/druid/query/topn/types/TopNColumnAggregatesProcessorFactory.java	Makes strategy-type switching explicit for non-supported types.
processing/src/main/java/org/apache/druid/query/PrioritizedExecutorService.java	Documents and suppresses intentional identity equality for prioritized future tasks.
processing/src/main/java/org/apache/druid/query/ordering/StringComparators.java	Documents and suppresses intentional string reference-equality fast paths.
processing/src/main/java/org/apache/druid/query/groupby/epinephelinae/ByteBufferMinMaxOffsetHeap.java	Fixes siftDown control flow to avoid non-terminating looping when no swap is needed.
processing/src/main/java/org/apache/druid/query/filter/InDimFilter.java	Uses modern instanceof pattern matching to avoid redundant casts while preserving behavior.
processing/src/main/java/org/apache/druid/math/expr/ExpressionTypeFactory.java	Makes array element-type switching explicit for ARRAY/COMPLEX.
processing/src/main/java/org/apache/druid/math/expr/ExpressionType.java	Makes column-type to expression-type mapping switches explicit for nested ARRAY/COMPLEX cases.
processing/src/main/java/org/apache/druid/java/util/common/guava/FunctionalIterator.java	Documents and suppresses intentional delegation of optional Iterator.remove.
processing/src/main/java/org/apache/druid/frame/field/FieldWriters.java	Explicitly rejects unsupported ARRAY/COMPLEX array element types with a targeted exception.
processing/src/main/java/org/apache/druid/extendedset/intset/ConciseSet.java	Documents and suppresses intentional non-short-circuit evaluation required for iterator advancement.
multi-stage-query/src/test/java/org/apache/druid/msq/kernel/controller/BaseControllerQueryKernelTest.java	Makes stage initialization explicitly reject an invalid RETRYING phase.
multi-stage-query/src/main/java/org/apache/druid/msq/indexing/processor/SegmentGeneratorFrameProcessor.java	Documents and suppresses intentional InputRow ordering/equality semantics during indexing.
multi-stage-query/src/main/java/org/apache/druid/msq/exec/ControllerHolder.java	Makes a state switch explicit for a RUNNING case in completion logic.
indexing-service/src/test/java/org/apache/druid/indexing/seekablestream/supervisor/SeekableStreamSupervisorTestBase.java	Documents and suppresses intentional ordering vs equality semantics for sequence numbers in tests.
indexing-service/src/test/java/org/apache/druid/indexing/seekablestream/supervisor/SeekableStreamSupervisorStateTest.java	Documents and suppresses intentional ordering vs equality semantics for sequence numbers in tests.
indexing-service/src/test/java/org/apache/druid/indexing/seekablestream/SeekableStreamIndexTaskRunnerTest.java	Documents and suppresses intentional ordering vs equality semantics for sequence numbers in tests.
indexing-service/src/main/java/org/apache/druid/indexing/common/task/Tasks.java	Documents and suppresses an intentional constant alignment check between independently-defined defaults.
extensions-core/kinesis-indexing-service/src/main/java/org/apache/druid/indexing/kinesis/KinesisSequenceNumber.java	Documents and suppresses intentional ordering vs identity semantics for special Kinesis markers.
extensions-core/kafka-indexing-service/src/main/java/org/apache/druid/indexing/kafka/KafkaSequenceNumber.java	Documents and suppresses intentional ordering/equality consistency for Kafka sequence numbers.
extensions-core/kafka-indexing-service/src/main/java/org/apache/druid/indexing/kafka/KafkaDataSourceMetadata.java	Documents and suppresses intentional natural ordering that excludes non-ordering config components.
extensions-core/histogram/src/main/java/org/apache/druid/query/aggregation/histogram/ApproximateHistogram.java	Fixes redundant loop control flow to reflect the single-iteration behavior.
extensions-core/ec2-extensions/src/test/java/org/apache/druid/indexing/overlord/autoscaling/ec2/EC2AutoScalerTest.java	Removes redundant constant assertions in EC2 autoscaler tests.
extensions-core/druid-bloom-filter/src/main/java/org/apache/druid/query/expressions/BloomFilterExpressions.java	Makes expression-type switching explicit for ARRAY/COMPLEX cases.
extensions-contrib/rabbit-stream-indexing-service/src/main/java/org/apache/druid/indexing/rabbitstream/RabbitSequenceNumber.java	Documents and suppresses intentional ordering/equality consistency for Rabbit sequence numbers.

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[FrankChen021]

I have reviewed the code for correctness, edge cases, concurrency, and integration risks; no issues found.

Reviewed 45 of 45 changed files.

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This is an automated review by Codex GPT-5.6-Sol