Add JMH benchmark for auto-mapping code by driessamyn · Pull Request #140 · driessamyn/kapper

driessamyn · 2025-06-20T16:28:14Z

This will facilate optimisation efforts.

qodo-free-for-open-source-projects · 2025-06-20T16:29:43Z

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
General	Make null logic deterministic The null determination logic uses modulo operation that could produce inconsistent results across benchmark runs due to the random seed. Consider using a deterministic approach based only on row and column indices for reproducible benchmarks. benchmark/src/main/kotlin/net/samyn/kapper/benchmark/mapper/ResultSetStub.kt [48] -private fun isNull(columnIndex: Int): Boolean = columnIndex in nullableColumns && (currentRow + columnIndex + random) % 2 != 0 +private fun isNull(columnIndex: Int): Boolean = columnIndex in nullableColumns && (currentRow + columnIndex) % 3 == 0 Apply / Chat Suggestion importance[1-10]: 8 __ Why: The suggestion correctly identifies that using a `random` value in the `isNull` check makes the benchmark's data generation non-deterministic. For reliable and reproducible benchmarks, the input data must be consistent across runs. The proposed change to a deterministic logic is a significant improvement.	Medium
	Replace assert with require Replace `assert` with `require` for better error handling in production benchmarks. The `assert` statement can be disabled with JVM flags, making the validation ineffective during actual benchmark runs. benchmark/src/jmh/kotlin/net/samyn/kapper/benchmark/AutoMapperBenchmark.kt [53-55] -assert(allResults.size == state.benchmarkStrategy.numberOfResults) { +require(allResults.size == state.benchmarkStrategy.numberOfResults) { "Expected ${state.benchmarkStrategy.numberOfResults} results, but got ${allResults.size}" } Apply / Chat Suggestion importance[1-10]: 6 __ Why: The suggestion to replace `assert` with `require` is valid. `assert` statements can be disabled at runtime using JVM flags, which would cause this important validation to be skipped. Using `require` ensures the check is always performed, making the benchmark more robust.	Low
	Enhance error message with JDBC type Include the JDBC type information in the error message to provide more context for debugging. This helps developers understand both the database type name and the corresponding JDBC type when conversion fails. core/src/main/kotlin/net/samyn/kapper/internal/automapper/SQLTypesConverter.kt [79-81] throw KapperUnsupportedOperationException( - "Conversion of field[${field.columnIndex}] from type ${field.typeName} is not supported", + "Conversion of field[${field.columnIndex}] from type ${field.typeName} (JDBC: ${field.jdbcType}) is not supported", ) Apply / Chat Suggestion importance[1-10]: 4 __ Why: This is a good suggestion for improving developer experience. Including the `jdbcType` in the exception message provides more specific information, which can aid in debugging unsupported type conversion issues.	Low
Organization best practice	Simplify interface implementation complexity This class implements the entire ResultSet interface with mostly NotImplementedError methods, making it overly complex. Consider creating a minimal interface or abstract class that only defines the methods actually needed for benchmarking. benchmark/src/main/kotlin/net/samyn/kapper/benchmark/mapper/ResultSetStub.kt [24-56] +interface BenchmarkResultSet { + fun next(): Boolean + fun getString(columnIndex: Int): String? + fun getInt(columnIndex: Int): Int + fun getBoolean(columnIndex: Int): Boolean + fun getDouble(columnIndex: Int): Double + fun close() +} + class ResultSetStub( private val rowCount: Int, private val nullableColumns: Set<Int> = emptySet(), private val uuidColumns: Set<Int> = emptySet(), -) : ResultSet { - private var currentRow = 0 - private val random = (System.currentTimeMillis() % 1234).toInt() - private val name = "Name-$random" +) : BenchmarkResultSet { + ... +} - override fun next(): Boolean { - return ++currentRow <= rowCount - } - ... - override fun <T : Any?> unwrap(iface: Class<T>?): T { - throw NotImplementedError() - } - ... - `[To ensure code accuracy, apply this suggestion manually]` Suggestion importance[1-10]: 6 __ Why: Relevant best practice - Keep It Simple, Stupid - systems work best if they are kept simple rather than made complex	Low
Update

Copilot

Pull Request Overview

This PR introduces a JMH benchmarking suite for the auto-mapping layer to help profile and optimize performance. Key changes:

Promote DbFlavour to a public API and update imports across tests and main code.
Add new benchmark classes and a script (run-mapper.sh) to run mapper performance tests via JMH.
Adjust JMH plugin configuration and refine exception messaging in SQLTypesConverter.

Reviewed Changes

Copilot reviewed 34 out of 36 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
coroutines/src/…/FlowQueryTest.kt	Switched import to public `DbFlavour`
coroutines/src/…/KapperKotlinFlowQueryFun.kt	Switched import to public `DbFlavour`
core/src/main/kotlin/.../SQLTypesConverter.kt	Refined unsupported-conversion exception message; imported public `DbFlavour`.
core/src/main/kotlin/.../DbFlavourFunc.kt	Removed internal `DbFlavour` enum and added import of public version
core/src/main/kotlin/net/samyn/kapper/DbFlavour.kt	Added public `DbFlavour` enum
core/src/test/kotlin/...	Updated dozens of tests to import public `DbFlavour`
benchmark/src/main/kotlin/...	Added `MapperBenchmark` interface and multiple mapper benchmarks
benchmark/src/jmh/.../AutoMapperBenchmark.kt	Added JMH benchmark harness for mapping scenarios
benchmark/run-mapper.sh	New script to build and execute the JMH benchmarks
benchmark/build.gradle.kts	Updated JMH plugin settings and added custom JMH tasks

github-actions · 2025-06-20T16:31:07Z

Code Coverage

File	Coverage [99.45%]
core/src/main/kotlin/net/samyn/kapper/DbFlavour.kt	100.00%
core/src/main/kotlin/net/samyn/kapper/Field.kt	100.00%
core/src/main/kotlin/net/samyn/kapper/internal/ArgsFun.kt	100.00%
core/src/main/kotlin/net/samyn/kapper/internal/DbFlavourFunc.kt	100.00%
core/src/main/kotlin/net/samyn/kapper/internal/Metadata.kt	100.00%
core/src/main/kotlin/net/samyn/kapper/internal/automapper/SQLTypesConverter.kt	99.21%
coroutines/src/main/kotlin/net/samyn/kapper/coroutines/KapperKotlinFlowQueryFun.kt	100.00%

Total Project Coverage	98.86%

github-actions · 2025-06-20T16:31:38Z

Unit Tests

42 files +1 42 suites +1 20s ⏱️ +3s
437 tests +4 437 ✅ +4 0 💤 ±0 0 ❌ ±0
452 runs +4 452 ✅ +4 0 💤 ±0 0 ❌ ±0

Results for commit b19566d. ± Comparison against base commit 965f4e2.

This pull request removes 42 and adds 45 tests. Note that renamed tests count towards both.


net.samyn.kapper.internal.QueryParserTest ‑ [5] 
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [10] LONGNVARCHAR, LONGNVARCHAR, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1021/0x00007fa2e84faba0@43755c41
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [11] INSTANT, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$913/0x00007fa2e84bb710@44e165e6
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [11] LONGVARCHAR, LONGVARCHAR, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1022/0x00007fa2e84fadc0@791cb215
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [12] DATE, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$914/0x00007fa2e84bb930@3ce3cd43
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [12] NCHAR, NCHAR, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1023/0x00007fa2e84fafe0@4dc2a4d1
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [13] LOCALDATE, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$915/0x00007fa2e84bbb50@57c64178
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [13] NCLOB, NCLOB, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1024/0x00007fa2e84fb200@39bfa161
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [14] LOCALDATETIME, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$916/0x00007fa2e84bbd70@5b484791
…

net.samyn.kapper.benchmark.mapper.MapperBenchmarkTest ‑ complex data class mapper should return mapped results()
net.samyn.kapper.benchmark.mapper.MapperBenchmarkTest ‑ complex record mapper should return mapped results()
net.samyn.kapper.benchmark.mapper.MapperBenchmarkTest ‑ simple data class mapper should return mapped results()
net.samyn.kapper.benchmark.mapper.MapperBenchmarkTest ‑ simple record mapper should return mapped results()
net.samyn.kapper.internal.QueryParserTest ‑ [5] 

net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [10] LONGNVARCHAR, LONGNVARCHAR, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1010/0x00007f3b4c4fe220@31949439
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [11] INSTANT, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$920/0x00007f3b4c4cfba0@65e296bf
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [11] LONGVARCHAR, LONGVARCHAR, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1011/0x00007f3b4c4fe440@164b7a56
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [12] DATE, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$921/0x00007f3b4c4cfdc0@81bc9c2
net.samyn.kapper.internal.automapper.SQLTypesConverterTest ‑ [12] NCHAR, NCHAR, net.samyn.kapper.internal.automapper.SQLTypesConverterTest$Companion$$Lambda$1012/0x00007f3b4c4fe660@56213c4b
…