Move to Gradle 8.11

The latest version of Gradle allows compiles on ARM64 (aarch64) to work.
This means one can build PJRmi natively on Raspbian. Also fix a couple
of issues spotted along the way.

Finally, move to a new subminor version, since we made enough changes
lately to warrant it.

gradle.properties

@@ -4,7 +4,7 @@ binpath=
 // string in the code. The minor value will be bumped for changes in the wire
 // format or major feature additions. The subminor version is typically bumped
 // for non-breaking changes, like bugfixes or minor enhancements.
-pjrmiVersion=1.13.11
+pjrmiVersion=1.13.12
 snappyVersion=1.1.0.1
 // Have a decent heap for the daemon
 org.gradle.jvmargs=-Xmx4g

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -80,13 +82,12 @@ do
     esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -133,22 +134,29 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -193,18 +201,28 @@ if "$cygwin" || "$msys" ; then
     done
 fi
 
-# Collect all arguments for the java command;
-#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \
         -classpath "$CLASSPATH" \
         org.gradle.wrapper.GradleWrapperMain \
         "$@"
 
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
 # Use "xargs" to parse quoted args.
 #
 # With -n1 it outputs one arg per line, with the quotes and backslashes removed.

java/src/main/java/com/deshaw/pjrmi/PJRmi.java

@@ -6286,7 +6286,7 @@ else if (valueFormat == PythonValueFormat.PYTHON_REFERENCE) {
 
             default:
                 throw new IllegalArgumentException(
-                    "Unhandled return format" + valueFormat
+                    "Unhandled return format " + valueFormat
                 );
             }
         }
@@ -9109,7 +9109,9 @@ protected byte[] initialValue()
                 "java.lang.IndexOutOfBoundsException",
                 "java.lang.Integer",
                 "java.lang.Iterable",
+                "java.lang.LinkageError",
                 "java.lang.Long",
+                "java.lang.NoClassDefFoundError",
                 "java.lang.NoSuchFieldException",
                 "java.lang.NoSuchMethodException",
                 "java.lang.Number",

python/tests/pjrmi_tests.py

@@ -133,6 +133,12 @@ def get_pjrmi():
 
     # Connect to PJRmi
     _pjrmi_connection = pjrmi.connect_to_child_jvm(
+        # We need around least 3Gb of heap for these tests but we give it a bit
+        # of headroom just in case. Some systems with a smaller memory footprint
+        # will have a smaller default heap size. It's safe to set the maximum
+        # value to higher number than the available memory, since the JVM will
+        # only allocate what it needs to.
+        java_args=("-Xmx4g",),
         # Turning class blocking on but allowing class injection does reduce
         # the fidelity of these tests compared to production but it's at least
         # better than not having class blocking.
@@ -759,10 +765,13 @@ def _kill_alive_process(pid):
         except IOError:
             child_python_pid, java_pid = (None, None)
 
-        # Now if we have found the file, we will wait for 1 second to let the
-        # processes cleanup.
+        # Now if we have found the file, we will wait for a bit to let the
+        # processes cleanup. This is a little racy in nature since the child can
+        # take longer to die on some systems so we try to do it vaguely nicely.
         if child_python_pid:
-            time.sleep(1)
+            for i in range(50):
+                if _kill_alive_process(child_python_pid):
+                    time.sleep(0.1)
 
         # Need to poll the parent process, so that it gets cleared from defunct
         # state, if it has exited.