Add cycles to core-beans: the circular-dependency failure report, what allow-circular-references repairs and hides, and four fixes on Boot 4.1

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Uu7q8vPeREyT4218EJPzz1

core-beans/scripts/capture-cycle-facts.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+# Two facts about the circular-reference machinery, read out of the Framework and Boot jars rather than from docs:
+#   36  the defaults of spring.main.allow-circular-references and spring.main.lazy-initialization
+#   37  which post-processors supply an early reference, and the exception handler in preInstantiateSingleton
+set -euo pipefail
+cd "$(dirname "$0")/.."
+mkdir -p output
+M2=~/.m2/repository/org/springframework
+BOOT=$M2/boot/spring-boot/4.1.1/spring-boot-4.1.1.jar
+AOP=$M2/spring-aop/7.0.9/spring-aop-7.0.9.jar
+CTX=$M2/spring-context/7.0.9/spring-context-7.0.9.jar
+BEANS=$M2/spring-beans/7.0.9/spring-beans-7.0.9.jar
+JP() { javap "$@" 2>&1 | grep -v '^Picked up'; }
+
+{
+  echo "# Defaults read from spring-configuration-metadata.json in spring-boot-4.1.1.jar"
+  echo
+  unzip -p "$BOOT" META-INF/spring-configuration-metadata.json | python3 -c '
+import json,sys
+d=json.load(sys.stdin)
+for p in d["properties"]:
+    if p["name"] in ("spring.main.allow-circular-references","spring.main.lazy-initialization"):
+        print("%-40s default=%s" % (p["name"], p.get("defaultValue")))
+'
+} > output/36-main-property-defaults.txt
+
+{
+  echo "# Who hands out an early reference, and the handler in preInstantiateSingleton (Spring Framework 7.0.9 jars)"
+  echo
+  echo "--- the class that draws the report, in spring-boot-4.1.1.jar ---"
+  unzip -l "$BOOT" | awk '/BeanCurrentlyInCreationFailureAnalyzer/ {print $4}'
+  echo
+  echo "--- AbstractAutoProxyCreator (spring-aop): declared methods that mention 'early' ---"
+  JP -p -cp "$AOP" org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator | grep -i early | sed 's/^ *//'
+  echo
+  echo "--- AbstractAdvisingBeanPostProcessor (spring-aop): declared members that mention 'early' ---"
+  n=$(JP -p -cp "$AOP" org.springframework.aop.framework.AbstractAdvisingBeanPostProcessor | grep -ci early || true)
+  echo "matches: $n"
+  echo
+  echo "--- the @Async post-processor's ancestry ---"
+  JP -cp "$CTX:$AOP" org.springframework.scheduling.annotation.AsyncAnnotationBeanPostProcessor | grep -o 'class [^ ]* extends [^ ]*'
+  JP -cp "$AOP" org.springframework.aop.framework.autoproxy.AbstractBeanFactoryAwareAdvisingPostProcessor | grep -o 'class [^ ]* extends [^ ]*'
+  echo
+  echo "--- DefaultListableBeanFactory.preInstantiateSingleton(String, RootBeanDefinition): exception table ---"
+  JP -p -c -cp "$BEANS" org.springframework.beans.factory.support.DefaultListableBeanFactory \
+    | awk '/private java.util.concurrent.CompletableFuture<\?> preInstantiateSingleton\(/ {f=1} f&&/Exception table:/ {t=1} t {print} t&&/^  private void instantiateSingletonInBackgroundThread/ {exit}' \
+    | grep -v 'instantiateSingletonInBackgroundThread' | sed 's/^ *//'
+} > output/37-early-reference-bytecode.txt
+cat output/36-main-property-defaults.txt output/37-early-reference-bytecode.txt

core-beans/scripts/run-all.sh

@@ -3,18 +3,21 @@
 #
 #   ./scripts/run-all.sh
 #
-# Needs a JDK 25 and Maven 3.9. Transcripts 01-17 and 19 come out of the test suite, which is the point:
-# the figures in the two articles are assertions that fail the build if they stop being true.
+# Needs a JDK 25 and Maven 3.9. Transcripts 01-17 and 19-35 come out of the test suite, which is the point:
+# the figures in the articles are assertions that fail the build if they stop being true.
 # Timing-based rows (12, 16) assert coarse thresholds, not exact milliseconds.
 set -euo pipefail
 cd "$(dirname "$0")/.."
 
-echo "== test suite (transcripts 01-17)"
+echo "== test suite (transcripts 01-17 and 19-35)"
 mvn -B test
 
 echo "== property defaults read from Boot's metadata (18)"
 ./scripts/capture-metadata.sh
 
+echo "== early-reference and property facts read from the jars (36-37)"
+./scripts/capture-cycle-facts.sh
+
 echo
 echo "output:"
 ls -1 output