GeezerVison

Fixes #1042.

Check the map size before allocating the interleaved key/value array in both MessageUnpacker.unpackValue() overloads. Pair counts from 2^30 through 2^31 - 1 now throw the existing MessageSizeException, with the declared count available through getSize(), instead of overflowing size * 2 and throwing NegativeArraySizeException. Larger unsigned headers retain their existing size exception.

The streaming unpackMapHeader() range is preserved. This change addresses the integer overflow during value materialization; it does not introduce a general memory limit or gradual allocation for #657.

Validation

The same 21 new AirSpec cases produced four expected errors before the fix and passed afterward; the other 17 cases passed on both versions. They cover both overloads, the overflow boundary, existing unsigned-size rejection, ordinary fixmap/map16/map32 values, nested maps, and streaming headers.

All 21 cases pass with both default and universal buffers on actual Java 8, 11, 17, 21 and 24 test JVMs. scalafmtCheckAll and jcheckStyle pass.

The existing pending entry is the malformed UTF-8 string case in MessagePackTest.

Broader local results:

The remaining universal Java 21 error is the unchanged DirectBufferAccessTest, which accesses MessageBuffer.unsafe when universal mode leaves it null. Of the 27 unchanged Jackson failures, 26 are null-pointer failures associated with the existing mixture of Jupiter test methods and JUnit 4 fixture lifecycle annotations. The remaining failure is testMessagePackParserDirectly(): its parser-location assertion expects 0 and receives -1, independently of those fixtures. These limitations were also documented in #1037 and were rechecked for this change. The stock sbt task does not discover the Jackson JUnit tests, so its zero-test result is not counted as a successful Jackson run.

AirSpec’s stock XML repeats leaf names for some nested tests. Additional full core runs used a verification-only copy of its event reporter that includes the actual parent test context in each name. Those reports contain 215 distinct testcase names and preserve the outcomes above; assertions, test execution, status and errors were unchanged. The 21 new regression cases and the focused Java-version matrix also passed with the unmodified reporter. This is not a claim that every project test is green. Remote CI has not run for this unpublished branch.

TEST_JAVA_HOME=/path/to/jdk21 ./sbt -batch \
  'msgpack-core/testOnly org.msgpack.core.MapSizeLimitTest'
./sbt -batch scalafmtCheckAll jcheckStyle

TEST_JAVA_HOME=/path/to/jdk21 ./sbt -batch \
  'msgpack-core/testOnly *'
TEST_JAVA_HOME=/path/to/jdk21 ./sbt -batch \
  'set msgpackCore / Test / javaOptions += "-Dmsgpack.universal-buffer=true"' \
  'msgpack-core/testOnly *'

TEST_JAVA_HOME=/path/to/jdk8 ./sbt -batch \
  'set msgpackCore / Compile / javacOptions ++= Seq("-bootclasspath", "/path/to/jdk8/jre/lib/rt.jar")' \
  'msgpack-core/testOnly *'
TEST_JAVA_HOME=/path/to/jdk8 ./sbt -batch \
  'set msgpackCore / Compile / javacOptions ++= Seq("-bootclasspath", "/path/to/jdk8/jre/lib/rt.jar")' \
  'set msgpackCore / Test / javaOptions += "-Dmsgpack.universal-buffer=true"' \
  'msgpack-core/testOnly *'

java -jar junit-platform-console-standalone-1.14.4.jar execute \
  --class-path '<msgpack-jackson Test/fullClasspath>' \
  --scan-class-path --include-package org.msgpack.jackson.dataformat \
  --fail-if-no-tests --details summary
java -jar junit-platform-console-standalone-1.14.4.jar execute \
  --class-path '<msgpack-jackson Test/fullClasspath>' \
  --select-class org.msgpack.jackson.dataformat.ExampleOfTypeInformationSerDe \
  --fail-if-no-tests --details summary