fix: improve Memoize test pass rate

Two independent fixes targeting failures seen in `jcpan -t Memoize`:

1. Storable::last_op_in_netorder: implement the flag that reports
   whether the most recent freeze/store used network byte order. Set by
   nfreeze()/nstore(), cleared by freeze()/store(). Unblocks
   t/tie_storable.t.

2. "Deep recursion on subroutine" warning: RuntimeCode now tracks
   per-sub recursion depth and warns (under the "recursion" category)
   the first time depth exceeds 100, matching Perl's
   PERL_SUB_DEPTH_WARN behavior. Map/grep/eval blocks and builtins are
   exempt. Unblocks t/correctness.t (which relied on the warning firing
   before StackOverflowError).

Test results for `jcpan -t Memoize` on this branch:
- Before: t/correctness.t crashed with StackOverflowError after test 16;
  t/tie_storable.t died at test 6 with "Undefined subroutine
  &Storable::last_op_in_netorder".
- After: correctness.t 17/17 pass; tie_storable.t 5/6 pass (test 6
  requires tied-hash DESTROY at scope exit, a separate pre-existing
  limitation).

threads->new / ->join stubs were considered but rejected: running a
thread body synchronously in the current thread silently produces
incorrect results whenever the code relies on thread isolation (as
Memoize's t/threadsafe.t test 8 demonstrated — unmemoize ran for real
on the main thread). Leaving t/threadsafe.t failing loudly is safer
than shipping a convincing-but-wrong stub.

t/tie.t and t/tie_db.t failures are caused by a broken user-local
DB_File.pm AUTOLOAD (CPAN-installed; DB_File needs XS and is not
supported on PerlOnJava) and are not addressed here.

Generated with [Devin](https://cli.devin.ai/docs)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: fglock

src/main/java/org/perlonjava/core/Configuration.java

@@ -33,7 +33,7 @@ public final class Configuration {
      * Automatically populated by Gradle/Maven during build.
      * DO NOT EDIT MANUALLY - this value is replaced at build time.
      */
-    public static final String gitCommitId = "c9b8e05dd";
+    public static final String gitCommitId = "fb4614791";
 
     /**
      * Git commit date of the build (ISO format: YYYY-MM-DD).
@@ -48,7 +48,7 @@ public final class Configuration {
      * Parsed by App::perlbrew and other tools via: perl -V | grep "Compiled at"
      * DO NOT EDIT MANUALLY - this value is replaced at build time.
      */
-    public static final String buildTimestamp = "Apr 20 2026 17:15:38";
+    public static final String buildTimestamp = "Apr 20 2026 18:52:44";
 
     // Prevent instantiation
     private Configuration() {

src/main/java/org/perlonjava/runtime/perlmodule/Storable.java

@@ -54,6 +54,7 @@ public static void initialize() {
             storable.registerMethod("retrieve", null);
             storable.registerMethod("nstore", null);
             storable.registerMethod("dclone", null);
+            storable.registerMethod("last_op_in_netorder", null);
 
             storable.defineExport("EXPORT", "store", "retrieve", "nstore", "freeze", "thaw", "nfreeze", "dclone");
 
@@ -82,12 +83,26 @@ public static void initialize() {
     // Magic byte to identify binary format (distinguishes from old YAML+GZIP format)
     private static final char BINARY_MAGIC = '\u00FF';
 
+    // Tracks whether the last freeze/store operation used network byte order.
+    // Set true by nfreeze()/nstore(); set false by freeze()/store().
+    // Exposed via Storable::last_op_in_netorder().
+    private static volatile boolean lastOpInNetorder = false;
+
+    /**
+     * Returns 1 if the last freeze/store operation used network byte order
+     * (i.e. was nfreeze or nstore), 0 otherwise.
+     */
+    public static RuntimeList last_op_in_netorder(RuntimeArray args, int ctx) {
+        return new RuntimeScalar(lastOpInNetorder ? 1 : 0).getList();
+    }
+
     /**
      * Freezes data to a binary format matching Perl 5 Storable's sort order.
      * Uses type bytes compatible with Perl 5's Storable so that string comparison
      * of frozen output produces the same ordering as Perl 5.
      */
     public static RuntimeList freeze(RuntimeArray args, int ctx) {
+        lastOpInNetorder = false;
         if (args.isEmpty()) {
             return WarnDie.die(new RuntimeScalar("freeze: not enough arguments"), new RuntimeScalar("\n")).getList();
         }
@@ -432,13 +447,16 @@ private static long readLong(String data, int[] pos) {
      * Network freeze (same as freeze for now).
      */
     public static RuntimeList nfreeze(RuntimeArray args, int ctx) {
-        return freeze(args, ctx);
+        RuntimeList result = freeze(args, ctx);
+        lastOpInNetorder = true;
+        return result;
     }
 
     /**
      * Stores data to file using YAML format.
      */
     public static RuntimeList store(RuntimeArray args, int ctx) {
+        lastOpInNetorder = false;
         if (args.size() < 2) {
             return WarnDie.die(new RuntimeScalar("store: not enough arguments"), new RuntimeScalar("\n")).getList();
         }
@@ -479,7 +497,9 @@ public static RuntimeList retrieve(RuntimeArray args, int ctx) {
      * Network store (same as store).
      */
     public static RuntimeList nstore(RuntimeArray args, int ctx) {
-        return store(args, ctx);
+        RuntimeList result = store(args, ctx);
+        lastOpInNetorder = true;
+        return result;
     }
 
     /**

src/main/java/org/perlonjava/runtime/runtimetypes/RuntimeCode.java

@@ -343,6 +343,72 @@ public static void clearInlineMethodCache() {
     public boolean isMapGrepBlock = false;
     // Flag to indicate this code is an eval BLOCK - non-local return should propagate through it
     public boolean isEvalBlock = false;
+
+    // Depth of active recursive calls to this subroutine, used by the
+    // "Deep recursion on subroutine" warning. Incremented on entry and
+    // decremented in a finally-block on exit.
+    public transient int callDepth = 0;
+    // Whether a "Deep recursion" warning has already been emitted for the
+    // currently-active recursion chain. Reset when callDepth returns to 0.
+    public transient boolean deepRecursionWarned = false;
+
+    // Depth threshold for the "Deep recursion on subroutine" warning.
+    // Matches Perl's default PERL_SUB_DEPTH_WARN value.
+    public static final int DEEP_RECURSION_WARN_DEPTH = 100;
+
+    // When the tail-call trampoline in the static apply() re-enters a sub,
+    // we want to skip the "Deep recursion" tracking for that entry.
+    // The goto &sub caller's `no warnings 'recursion'` scope has already
+    // unwound by the time the trampoline runs, so we can't honor it; and
+    // tail calls don't consume real Java stack, so a depth warning for
+    // them is misleading anyway. Nested tail-call trampolines use an int
+    // counter so re-entries only skip tracking for the outermost trampoline.
+    private static final ThreadLocal<Integer> inTailCallTrampoline =
+            ThreadLocal.withInitial(() -> 0);
+
+    /**
+     * Increment the recursion depth counter and, if we've just crossed the
+     * "Deep recursion on subroutine" threshold for the first time in this
+     * recursion chain, emit a warning under the "recursion" warnings category.
+     * Must be matched with a call to exitCall() in a finally-block.
+     *
+     * Map/grep/eval blocks are exempt so that map { ... } and eval { ... }
+     * don't report their dispatch wrapper. Tail-call trampoline re-entries
+     * are also exempt — see inTailCallTrampoline.
+     */
+    private void enterCall() {
+        if (isMapGrepBlock || isEvalBlock || isBuiltin) {
+            return;
+        }
+        if (inTailCallTrampoline.get() > 0) {
+            return;
+        }
+        int depth = ++callDepth;
+        if (depth > DEEP_RECURSION_WARN_DEPTH && !deepRecursionWarned) {
+            deepRecursionWarned = true;
+            String name = (packageName != null && subName != null)
+                    ? packageName + "::" + subName
+                    : (subName != null ? subName : "__ANON__");
+            WarnDie.warnWithCategory(
+                    new RuntimeScalar("Deep recursion on subroutine \"" + name + "\""),
+                    RuntimeScalarCache.scalarEmptyString,
+                    "recursion");
+        }
+    }
+
+    /** Paired with enterCall() — decrements the recursion counter. */
+    private void exitCall() {
+        if (isMapGrepBlock || isEvalBlock || isBuiltin) {
+            return;
+        }
+        if (inTailCallTrampoline.get() > 0) {
+            return;
+        }
+        if (--callDepth <= 0) {
+            callDepth = 0;
+            deepRecursionWarned = false;
+        }
+    }
     // State variables
     public Map<String, Boolean> stateVariableInitialized = new HashMap<>();
     public Map<String, RuntimeScalar> stateVariable = new HashMap<>();
@@ -2330,7 +2396,16 @@ public static RuntimeList apply(RuntimeScalar runtimeScalar, RuntimeArray a, int
                         && cfList.getControlFlowType() == ControlFlowType.TAILCALL) {
                     RuntimeScalar tailCodeRef = cfList.getTailCallCodeRef();
                     RuntimeArray tailArgs = cfList.getTailCallArgs();
-                    result = apply(tailCodeRef, tailArgs != null ? tailArgs : a, callContext);
+                    // Mark trampoline re-entry so enterCall/exitCall skip depth
+                    // tracking (tail calls don't consume real Java stack, and the
+                    // goto site's lexical `no warnings 'recursion'` scope has
+                    // already unwound — see enterCall() comments).
+                    inTailCallTrampoline.set(inTailCallTrampoline.get() + 1);
+                    try {
+                        result = apply(tailCodeRef, tailArgs != null ? tailArgs : a, callContext);
+                    } finally {
+                        inTailCallTrampoline.set(inTailCallTrampoline.get() - 1);
+                    }
                 }
                 // Mortal-ize blessed refs with refCount==0 in void-context calls.
                 // These are objects that were created but never stored in a named
@@ -2669,6 +2744,23 @@ public static RuntimeList apply(RuntimeScalar runtimeScalar, String subroutineNa
     // Method to apply (execute) a subroutine reference (legacy method for compatibility)
     public static RuntimeList apply(RuntimeScalar runtimeScalar, String subroutineName, RuntimeBase list, int callContext) {
 
+        // If this is a tail-call trampoline re-entry (emitted by the JVM bytecode
+        // trampoline for `goto &sub`), mark it so enterCall/exitCall skip depth
+        // tracking. See enterCall() / inTailCallTrampoline for the rationale.
+        boolean isTailCall = "tailcall".equals(subroutineName);
+        if (isTailCall) {
+            inTailCallTrampoline.set(inTailCallTrampoline.get() + 1);
+            try {
+                return applyImpl(runtimeScalar, subroutineName, list, callContext);
+            } finally {
+                inTailCallTrampoline.set(inTailCallTrampoline.get() - 1);
+            }
+        }
+        return applyImpl(runtimeScalar, subroutineName, list, callContext);
+    }
+
+    private static RuntimeList applyImpl(RuntimeScalar runtimeScalar, String subroutineName, RuntimeBase list, int callContext) {
+
         // Handle tied scalars - fetch the underlying value first
         if (runtimeScalar.type == RuntimeScalarType.TIED_SCALAR) {
             return apply(runtimeScalar.tiedFetch(), subroutineName, list, callContext);
@@ -3163,6 +3255,11 @@ public RuntimeList apply(RuntimeArray a, int callContext) {
             // See also: the 3-arg instance method apply(name, array, ctx) which pushes true.
             hasArgsStack.get().push(false);
 
+            // Check deep recursion BEFORE pushing the callee's warning bits,
+            // so the "Deep recursion on subroutine" warning is gated on the
+            // caller's lexical warning bits (matching Perl's ckWARN at the
+            // call site, not inside the callee).
+            enterCall();
             // Push warning bits for FATAL warnings support
             String warningBits = getWarningBitsForCode(this);
             if (warningBits != null) {
@@ -3183,6 +3280,7 @@ public RuntimeList apply(RuntimeArray a, int callContext) {
                 if (warningBits != null) {
                     WarningBitsRegistry.popCurrent();
                 }
+                exitCall();
                 popArgs(); // also pops hasArgsStack — see popArgs() implementation
                 if (DebugState.debugMode) {
                     DebugHooks.exitSubroutine();
@@ -3268,6 +3366,10 @@ public RuntimeList apply(String subroutineName, RuntimeArray a, int callContext)
             // See also: the 2-arg instance method apply(array, ctx) which pushes false.
             hasArgsStack.get().push(true);
 
+            // Check deep recursion BEFORE pushing the callee's warning bits,
+            // so the "Deep recursion on subroutine" warning is gated on the
+            // caller's lexical warning bits.
+            enterCall();
             // Push warning bits for FATAL warnings support
             String warningBits = getWarningBitsForCode(this);
             if (warningBits != null) {
@@ -3288,6 +3390,7 @@ public RuntimeList apply(String subroutineName, RuntimeArray a, int callContext)
                 if (warningBits != null) {
                     WarningBitsRegistry.popCurrent();
                 }
+                exitCall();
                 popArgs(); // also pops hasArgsStack — see popArgs() implementation
                 if (DebugState.debugMode) {
                     DebugHooks.exitSubroutine();