[pitboss] phase 20: Track M.2 — MessageHandler end-to-end (Kafka / SQS / Pub-Sub / NATS / RabbitMQ)

tests/dynamic_fixtures/message_handler/kafka_java/Benign.java

@@ -0,0 +1,9 @@
+// Phase 20 (Track M.2) — Kafka Java benign control.
+// `org.springframework.kafka` adapter marker preserved.
+public class Benign {
+    public Benign() {}
+
+    public void onMessage(String body) throws Exception {
+        new ProcessBuilder("echo", body).inheritIO().start().waitFor();
+    }
+}

tests/dynamic_fixtures/message_handler/kafka_java/Vuln.java

@@ -0,0 +1,15 @@
+// Phase 20 (Track M.2) — Kafka Java vuln fixture.
+//
+// Marker line so the kafka-java framework adapter binds:
+// `org.springframework.kafka` consumer entry point.  Annotation is
+// elided so javac compiles without the Spring jar; the dynamic harness
+// invokes onMessage reflectively.
+
+public class Vuln {
+    public Vuln() {}
+
+    public void onMessage(String body) throws Exception {
+        // SINK: tainted body concatenated into shell command
+        new ProcessBuilder("sh", "-c", "echo " + body).inheritIO().start().waitFor();
+    }
+}

tests/dynamic_fixtures/message_handler/kafka_python/benign.py

@@ -0,0 +1,9 @@
+"""Phase 20 (Track M.2) — Kafka Python benign control."""
+import os
+import shlex
+
+_NYX_ADAPTER_MARKER = "from kafka import KafkaConsumer"
+
+
+def handler(message):
+    os.system("echo " + shlex.quote(str(message)))

tests/dynamic_fixtures/message_handler/kafka_python/vuln.py

@@ -0,0 +1,25 @@
+"""Phase 20 (Track M.2) — Kafka Python vuln fixture.
+
+`handler` is a Kafka consumer callback (modelled after
+`KafkaConsumer('orders').poll()` dispatch) that splices the raw
+message body into a shell command via `os.system`.  A malicious
+producer can inject command-separator metacharacters into the body
+and the shell will execute them — the classic message-handler cmdi
+shape.
+
+Adapter source-marker: `from kafka import KafkaConsumer` is kept as a
+docstring reference (not a top-level import) so the harness can run
+without the real `kafka-python` library installed on the host.
+"""
+import os
+
+# Phase 20 framework adapter detects this fixture via the `from kafka`
+# / `import kafka` substring scan.  Keeping the marker in source lets
+# the adapter bind without forcing the host to pin the kafka-python
+# pip dep just to load the fixture module.
+_NYX_ADAPTER_MARKER = "from kafka import KafkaConsumer"
+
+
+def handler(message):
+    # SINK: tainted message body concatenated into shell command
+    os.system("echo " + str(message))

tests/dynamic_fixtures/message_handler/nats_go/benign.go

@@ -0,0 +1,19 @@
+// Phase 20 (Track M.2) — NATS Go benign control.
+package entry
+
+import (
+	"os"
+	"os/exec"
+)
+
+const _adapterMarker = "github.com/nats-io/nats.go"
+
+func OnMessage(payload string) {
+	cmd := exec.Command("echo", payload)
+	out, _ := cmd.Output()
+	os.Stdout.Write(out)
+}
+
+var NyxHandlers = map[string]interface{}{
+	"OnMessage": OnMessage,
+}

tests/dynamic_fixtures/message_handler/nats_go/vuln.go

@@ -0,0 +1,22 @@
+// Phase 20 (Track M.2) — NATS Go vuln fixture.
+//
+// Adapter source-marker: github.com/nats-io/nats.go (string-literal only).
+package entry
+
+import (
+	"os"
+	"os/exec"
+)
+
+const _adapterMarker = "github.com/nats-io/nats.go"
+
+func OnMessage(payload string) {
+	// SINK: tainted payload concatenated into shell command
+	cmd := exec.Command("sh", "-c", "echo "+payload)
+	out, _ := cmd.Output()
+	os.Stdout.Write(out)
+}
+
+var NyxHandlers = map[string]interface{}{
+	"OnMessage": OnMessage,
+}

tests/dynamic_fixtures/message_handler/pubsub_go/benign.go

@@ -0,0 +1,19 @@
+// Phase 20 (Track M.2) — Google Pub/Sub Go benign control.
+package entry
+
+import (
+	"os"
+	"os/exec"
+)
+
+const _adapterMarker = "cloud.google.com/go/pubsub"
+
+func OnMessage(payload string) {
+	cmd := exec.Command("echo", payload)
+	out, _ := cmd.Output()
+	os.Stdout.Write(out)
+}
+
+var NyxHandlers = map[string]interface{}{
+	"OnMessage": OnMessage,
+}

tests/dynamic_fixtures/message_handler/pubsub_go/vuln.go

@@ -0,0 +1,24 @@
+// Phase 20 (Track M.2) — Google Pub/Sub Go vuln fixture.
+//
+// Adapter source-marker: cloud.google.com/go/pubsub (string-literal only).
+// The handler signature accepts a string so the Phase 20 harness
+// dispatch falls through to the NYX_PAYLOAD env var.
+package entry
+
+import (
+	"os"
+	"os/exec"
+)
+
+const _adapterMarker = "cloud.google.com/go/pubsub"
+
+func OnMessage(payload string) {
+	// SINK: tainted payload concatenated into shell command
+	cmd := exec.Command("sh", "-c", "echo "+payload)
+	out, _ := cmd.Output()
+	os.Stdout.Write(out)
+}
+
+var NyxHandlers = map[string]interface{}{
+	"OnMessage": OnMessage,
+}

tests/dynamic_fixtures/message_handler/pubsub_python/benign.py

@@ -0,0 +1,21 @@
+"""Phase 20 (Track M.2) — Google Pub/Sub Python benign control."""
+import os
+import shlex
+
+_NYX_ADAPTER_MARKER = "from google.cloud import pubsub_v1"
+_NYX_TOPIC_MARKER = '.subscribe("projects/p/subscriptions/s"'
+
+
+def callback(message):
+    body = getattr(message, 'data', None)
+    if body is None and isinstance(message, dict):
+        body = message.get('data')
+    if isinstance(body, (bytes, bytearray)):
+        body = body.decode('utf-8', 'replace')
+    if body is None:
+        body = str(message)
+    os.system("echo " + shlex.quote(body))
+    try:
+        message.ack()
+    except Exception:
+        pass

tests/dynamic_fixtures/message_handler/pubsub_python/vuln.py

@@ -0,0 +1,28 @@
+"""Phase 20 (Track M.2) — Google Pub/Sub Python vuln fixture.
+
+`callback` is a `pubsub_v1.SubscriberClient.subscribe` callback that
+takes `message.data` bytes straight into a shell command.
+
+Adapter marker kept as a string literal so the google-cloud-pubsub dep
+is not required to load the module.
+"""
+import os
+
+_NYX_ADAPTER_MARKER = "from google.cloud import pubsub_v1"
+_NYX_TOPIC_MARKER = '.subscribe("projects/p/subscriptions/s"'
+
+
+def callback(message):
+    body = getattr(message, 'data', None)
+    if body is None and isinstance(message, dict):
+        body = message.get('data')
+    if isinstance(body, (bytes, bytearray)):
+        body = body.decode('utf-8', 'replace')
+    if body is None:
+        body = str(message)
+    # SINK: tainted message body concatenated into shell command
+    os.system("echo " + body)
+    try:
+        message.ack()
+    except Exception:
+        pass

tests/dynamic_fixtures/message_handler/rabbit_java/Benign.java

@@ -0,0 +1,10 @@
+// Phase 20 (Track M.2) — RabbitMQ Java benign control.
+// `org.springframework.amqp.rabbit` adapter marker preserved.
+
+public class Benign {
+    public Benign() {}
+
+    public void onMessage(String messageId, String body) throws Exception {
+        new ProcessBuilder("echo", body).inheritIO().start().waitFor();
+    }
+}

tests/dynamic_fixtures/message_handler/rabbit_java/Vuln.java

@@ -0,0 +1,12 @@
+// Phase 20 (Track M.2) — RabbitMQ Java vuln fixture.
+// `org.springframework.amqp.rabbit` consumer marker preserved;
+// annotation elided so javac compiles without the Spring AMQP jar.
+
+public class Vuln {
+    public Vuln() {}
+
+    public void onMessage(String messageId, String body) throws Exception {
+        // SINK: tainted body concatenated into shell command
+        new ProcessBuilder("sh", "-c", "echo " + body).inheritIO().start().waitFor();
+    }
+}

tests/dynamic_fixtures/message_handler/rabbit_python/benign.py

@@ -0,0 +1,12 @@
+"""Phase 20 (Track M.2) — RabbitMQ Python benign control."""
+import os
+import shlex
+
+_NYX_ADAPTER_MARKER = "import pika"
+_NYX_QUEUE_MARKER = 'queue="work"'
+
+
+def on_message(ch, method, properties, body):
+    if isinstance(body, (bytes, bytearray)):
+        body = body.decode('utf-8', 'replace')
+    os.system("echo " + shlex.quote(body))

tests/dynamic_fixtures/message_handler/rabbit_python/vuln.py

@@ -0,0 +1,19 @@
+"""Phase 20 (Track M.2) — RabbitMQ Python vuln fixture.
+
+`on_message` is a `pika.BlockingConnection.channel.basic_consume`
+callback whose body argument flows into a shell command.
+
+Adapter marker kept as a string literal so the pika dep is not
+required to load the module.
+"""
+import os
+
+_NYX_ADAPTER_MARKER = "import pika"
+_NYX_QUEUE_MARKER = 'queue="work"'
+
+
+def on_message(ch, method, properties, body):
+    if isinstance(body, (bytes, bytearray)):
+        body = body.decode('utf-8', 'replace')
+    # SINK: tainted body concatenated into shell command
+    os.system("echo " + body)

tests/dynamic_fixtures/message_handler/sqs_java/Benign.java

@@ -0,0 +1,11 @@
+// Phase 20 (Track M.2) — SQS Java benign control.
+// `io.awspring.cloud.sqs` adapter marker preserved.
+
+public class Benign {
+    public Benign() {}
+
+    public void handleMessage(java.util.Map<String, String> env) throws Exception {
+        String body = env != null ? env.getOrDefault("Body", "") : "";
+        new ProcessBuilder("echo", body).inheritIO().start().waitFor();
+    }
+}

tests/dynamic_fixtures/message_handler/sqs_java/Vuln.java

@@ -0,0 +1,13 @@
+// Phase 20 (Track M.2) — SQS Java vuln fixture.
+// `io.awspring.cloud.sqs` consumer entry point — annotation elided so
+// javac compiles without the Spring Cloud AWS jar.
+
+public class Vuln {
+    public Vuln() {}
+
+    public void handleMessage(java.util.Map<String, String> env) throws Exception {
+        String body = env != null ? env.getOrDefault("Body", "") : "";
+        // SINK: tainted Body concatenated into shell command
+        new ProcessBuilder("sh", "-c", "echo " + body).inheritIO().start().waitFor();
+    }
+}

tests/dynamic_fixtures/message_handler/sqs_node/benign.js

@@ -0,0 +1,16 @@
+// Phase 20 (Track M.2) — SQS Node benign control.
+const { execFileSync } = require('child_process');
+
+const _markerRequire = "require('sqs-consumer')";
+const _markerImport = "@aws-sdk/client-sqs";
+
+function handler(envelope) {
+    const body = (envelope && envelope.Body) ? envelope.Body : '';
+    try {
+        const out = execFileSync('echo', [body]).toString();
+        process.stdout.write(out);
+    } catch (_e) {
+    }
+}
+
+module.exports = { handler };

tests/dynamic_fixtures/message_handler/sqs_node/vuln.js

@@ -0,0 +1,22 @@
+// Phase 20 (Track M.2) — SQS Node vuln fixture.
+// `sqs-consumer` handler that concatenates the envelope's Body into a
+// shell command — classic message-handler cmdi.
+const { execSync } = require('child_process');
+
+// Adapter source-marker: require('sqs-consumer') (string-literal only)
+const _markerRequire = "require('sqs-consumer')";
+const _markerImport = "@aws-sdk/client-sqs";
+
+function handler(envelope) {
+    const body = (envelope && envelope.Body) ? envelope.Body : '';
+    // SINK: tainted Body concatenated into shell command
+    try {
+        const out = execSync('echo ' + body).toString();
+        process.stdout.write(out);
+    } catch (_e) {
+        // surface stderr on the harness's stderr; the oracle reads
+        // stdout
+    }
+}
+
+module.exports = { handler };

tests/dynamic_fixtures/message_handler/sqs_python/benign.py

@@ -0,0 +1,10 @@
+"""Phase 20 (Track M.2) — SQS Python benign control."""
+import os
+import shlex
+
+_NYX_ADAPTER_MARKER = "boto3.client('sqs')"
+
+
+def handler(envelope):
+    body = envelope.get('Body', '') if isinstance(envelope, dict) else str(envelope)
+    os.system("echo " + shlex.quote(body))

tests/dynamic_fixtures/message_handler/sqs_python/vuln.py

@@ -0,0 +1,17 @@
+"""Phase 20 (Track M.2) — SQS Python vuln fixture.
+
+`handler` is a boto3 SQS poller callback that takes the raw envelope's
+`Body` field straight into a shell command.
+
+Adapter marker kept as a string literal so the boto3 dep is not
+required to load the module.
+"""
+import os
+
+_NYX_ADAPTER_MARKER = "boto3.client('sqs')"
+
+
+def handler(envelope):
+    body = envelope.get('Body', '') if isinstance(envelope, dict) else str(envelope)
+    # SINK: tainted Body concatenated into shell command
+    os.system("echo " + body)

tests/message_handler_corpus.rs

@@ -0,0 +1,555 @@
+//! Phase 20 (Track M.2) — `MessageHandler` end-to-end acceptance.
+//!
+//! Asserts the new `EntryKind::MessageHandler { queue, message_schema }`
+//! variant is supported by the per-language emitters the brief targets
+//! (Python, Java, JavaScript, TypeScript, Go) so the
+//! `Inconclusive(EntryKindUnsupported { attempted: MessageHandler })`
+//! rate drops to 0% across those five languages.  Also exercises the
+//! 10 Phase 20 framework adapters (`kafka-python`, `kafka-java`,
+//! `sqs-python`, `sqs-java`, `sqs-node`, `pubsub-python`, `pubsub-go`,
+//! `rabbit-python`, `rabbit-java`, `nats-go`) against the fixtures
+//! under `tests/dynamic_fixtures/message_handler/`.
+//!
+//! `cargo nextest run --features dynamic --test message_handler_corpus`.
+
+#![cfg(feature = "dynamic")]
+
+mod common;
+
+use nyx_scanner::dynamic::framework::registry::adapters_for;
+use nyx_scanner::dynamic::framework::{detect_binding, FrameworkBinding};
+use nyx_scanner::dynamic::lang;
+use nyx_scanner::dynamic::spec::{EntryKind, EntryKindTag, HarnessSpec, PayloadSlot};
+use nyx_scanner::labels::Cap;
+use nyx_scanner::summary::FuncSummary;
+use nyx_scanner::symbol::Lang;
+
+const SUPPORTED_LANGS: &[Lang] = &[
+    Lang::Python,
+    Lang::Java,
+    Lang::JavaScript,
+    Lang::TypeScript,
+    Lang::Go,
+];
+
+const UNSUPPORTED_LANGS: &[Lang] = &[
+    Lang::Php,
+    Lang::Ruby,
+    Lang::Rust,
+    Lang::C,
+    Lang::Cpp,
+];
+
+fn entry_file(broker_lang: &str) -> &'static str {
+    // Phase 20 fixtures live at tests/dynamic_fixtures/message_handler/{broker_lang}/{vuln,benign}.
+    match broker_lang {
+        "kafka_python" => "tests/dynamic_fixtures/message_handler/kafka_python/vuln.py",
+        "kafka_java" => "tests/dynamic_fixtures/message_handler/kafka_java/Vuln.java",
+        "sqs_python" => "tests/dynamic_fixtures/message_handler/sqs_python/vuln.py",
+        "sqs_java" => "tests/dynamic_fixtures/message_handler/sqs_java/Vuln.java",
+        "sqs_node" => "tests/dynamic_fixtures/message_handler/sqs_node/vuln.js",
+        "pubsub_python" => "tests/dynamic_fixtures/message_handler/pubsub_python/vuln.py",
+        "pubsub_go" => "tests/dynamic_fixtures/message_handler/pubsub_go/vuln.go",
+        "rabbit_python" => "tests/dynamic_fixtures/message_handler/rabbit_python/vuln.py",
+        "rabbit_java" => "tests/dynamic_fixtures/message_handler/rabbit_java/Vuln.java",
+        "nats_go" => "tests/dynamic_fixtures/message_handler/nats_go/vuln.go",
+        other => panic!("unknown broker_lang fixture {other}"),
+    }
+}
+
+fn make_spec(lang: Lang, queue: &str, handler: &str, fixture: &str) -> HarnessSpec {
+    HarnessSpec {
+        finding_id: "phase20msghandler".into(),
+        entry_file: fixture.into(),
+        entry_name: handler.into(),
+        entry_kind: EntryKind::MessageHandler {
+            queue: queue.into(),
+            message_schema: None,
+        },
+        lang,
+        toolchain_id: "phase20".into(),
+        payload_slot: PayloadSlot::Param(0),
+        expected_cap: Cap::CODE_EXEC,
+        constraint_hints: vec![],
+        sink_file: fixture.into(),
+        sink_line: 1,
+        spec_hash: "phase20msghandler".into(),
+        derivation: nyx_scanner::dynamic::spec::SpecDerivationStrategy::FromFlowSteps,
+        stubs_required: vec![],
+        framework: None,
+        java_toolchain: nyx_scanner::dynamic::spec::JavaToolchain::default(),
+    }
+}
+
+// ── Supported-set assertions ──────────────────────────────────────────────────
+
+#[test]
+fn message_handler_supported_by_phase_20_lang_emitters() {
+    for lang in SUPPORTED_LANGS {
+        let supported = lang::entry_kinds_supported(*lang);
+        assert!(
+            supported.contains(&EntryKindTag::MessageHandler),
+            "{lang:?} must advertise MessageHandler after Phase 20; supported = {supported:?}",
+        );
+    }
+}
+
+#[test]
+fn message_handler_not_supported_outside_phase_20_langs() {
+    for lang in UNSUPPORTED_LANGS {
+        let supported = lang::entry_kinds_supported(*lang);
+        assert!(
+            !supported.contains(&EntryKindTag::MessageHandler),
+            "{lang:?} must not yet advertise MessageHandler — Phase 20 only covers 5 langs; got {supported:?}",
+        );
+    }
+}
+
+#[test]
+fn message_handler_emit_does_not_short_circuit_for_supported_langs() {
+    let cases: &[(Lang, &str, &str, &str)] = &[
+        (Lang::Python, "kafka_python", "orders", "handler"),
+        (Lang::Java, "kafka_java", "orders", "onMessage"),
+        (Lang::JavaScript, "sqs_node", "jobs", "handler"),
+        (Lang::TypeScript, "sqs_node", "jobs", "handler"),
+        (Lang::Go, "pubsub_go", "my-sub", "OnMessage"),
+    ];
+    for (lang, broker_lang, queue, handler) in cases {
+        let spec = make_spec(*lang, queue, handler, entry_file(broker_lang));
+        let result = lang::emit(&spec);
+        assert!(
+            result.is_ok(),
+            "{lang:?} emit returned {result:?} for MessageHandler spec",
+        );
+    }
+}
+
+#[test]
+fn message_handler_harness_carries_queue_and_handler_literals() {
+    let cases: &[(Lang, &str, &str, &str)] = &[
+        (Lang::Python, "kafka_python", "orders", "handler"),
+        (Lang::Java, "kafka_java", "orders", "onMessage"),
+        (Lang::JavaScript, "sqs_node", "jobs", "handler"),
+        (Lang::Go, "pubsub_go", "my-sub", "OnMessage"),
+    ];
+    for (lang, broker_lang, queue, handler) in cases {
+        let spec = make_spec(*lang, queue, handler, entry_file(broker_lang));
+        let h = lang::emit(&spec).expect("emit ok");
+        assert!(
+            h.source.contains(queue),
+            "{lang:?} harness must reference queue {queue:?}; source: {}",
+            h.source
+        );
+        assert!(
+            h.source.contains(handler),
+            "{lang:?} harness must reference handler {handler:?}",
+        );
+    }
+}
+
+#[test]
+fn message_handler_python_dispatch_subscribes_to_loopback() {
+    let spec = make_spec(
+        Lang::Python,
+        "orders",
+        "handler",
+        entry_file("kafka_python"),
+    );
+    let h = lang::emit(&spec).expect("emit ok");
+    assert!(h.source.contains("NyxKafkaLoopback"));
+    assert!(h.source.contains("subscribe"));
+    assert!(h.source.contains("__NYX_BROKER_PUBLISH__"));
+    assert!(h.source.contains("payload"));
+}
+
+#[test]
+fn message_handler_java_emits_reflective_dispatch() {
+    let spec = make_spec(Lang::Java, "orders", "onMessage", entry_file("kafka_java"));
+    let h = lang::emit(&spec).expect("emit ok");
+    assert!(h.source.contains("NyxKafkaLoopback"));
+    assert!(h.source.contains("Class.forName"));
+    assert!(h.source.contains("getDeclaredMethod"));
+}
+
+#[test]
+fn message_handler_node_uses_sqs_loopback() {
+    let spec = make_spec(Lang::JavaScript, "jobs", "handler", entry_file("sqs_node"));
+    let h = lang::emit(&spec).expect("emit ok");
+    assert!(h.source.contains("NyxSqsLoopback"));
+    assert!(h.source.contains("subscribe"));
+    assert!(h.source.contains("__NYX_BROKER_PUBLISH__:sqs"));
+}
+
+#[test]
+fn message_handler_go_uses_nyx_handlers_registry() {
+    let spec = make_spec(Lang::Go, "my-sub", "OnMessage", entry_file("pubsub_go"));
+    let h = lang::emit(&spec).expect("emit ok");
+    assert!(h.source.contains("entry.NyxHandlers"));
+    assert!(h.source.contains("NewNyxPubsubLoopback"));
+}
+
+// ── Framework-adapter assertions ──────────────────────────────────────────────
+
+fn ts_language_for(lang: Lang) -> tree_sitter::Language {
+    match lang {
+        Lang::Java => tree_sitter::Language::from(tree_sitter_java::LANGUAGE),
+        Lang::Python => tree_sitter::Language::from(tree_sitter_python::LANGUAGE),
+        Lang::JavaScript => tree_sitter::Language::from(tree_sitter_javascript::LANGUAGE),
+        Lang::Go => tree_sitter::Language::from(tree_sitter_go::LANGUAGE),
+        other => panic!("unsupported test lang {other:?}"),
+    }
+}
+
+fn detect_for(lang: Lang, fixture: &str, handler: &str) -> Option<FrameworkBinding> {
+    let bytes = std::fs::read(fixture).expect("fixture exists");
+    let ts_lang = ts_language_for(lang);
+    let mut parser = tree_sitter::Parser::new();
+    parser.set_language(&ts_lang).unwrap();
+    let tree = parser.parse(&bytes, None).unwrap();
+    let summary = FuncSummary {
+        name: handler.into(),
+        ..Default::default()
+    };
+    detect_binding(&summary, tree.root_node(), &bytes, lang)
+}
+
+#[test]
+fn kafka_python_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Python, entry_file("kafka_python"), "handler")
+        .expect("kafka-python detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn kafka_java_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Java, entry_file("kafka_java"), "onMessage")
+        .expect("kafka-java detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn sqs_python_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Python, entry_file("sqs_python"), "handler")
+        .expect("sqs-python detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn sqs_java_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Java, entry_file("sqs_java"), "handleMessage")
+        .expect("sqs-java detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn sqs_node_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::JavaScript, entry_file("sqs_node"), "handler")
+        .expect("sqs-node detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn pubsub_python_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Python, entry_file("pubsub_python"), "callback")
+        .expect("pubsub-python detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn pubsub_go_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Go, entry_file("pubsub_go"), "OnMessage")
+        .expect("pubsub-go detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn rabbit_python_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Python, entry_file("rabbit_python"), "on_message")
+        .expect("rabbit-python detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn rabbit_java_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Java, entry_file("rabbit_java"), "onMessage")
+        .expect("rabbit-java detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn nats_go_adapter_binds_message_handler_kind() {
+    let b = detect_for(Lang::Go, entry_file("nats_go"), "OnMessage")
+        .expect("nats-go detect");
+    assert!(matches!(b.kind, EntryKind::MessageHandler { .. }));
+}
+
+#[test]
+fn registry_slices_include_phase_20_adapters() {
+    let java_names: Vec<&'static str> = adapters_for(Lang::Java)
+        .iter()
+        .map(|a| a.name())
+        .collect();
+    assert!(java_names.contains(&"kafka-java"));
+    assert!(java_names.contains(&"sqs-java"));
+    assert!(java_names.contains(&"rabbit-java"));
+
+    let python_names: Vec<&'static str> = adapters_for(Lang::Python)
+        .iter()
+        .map(|a| a.name())
+        .collect();
+    assert!(python_names.contains(&"kafka-python"));
+    assert!(python_names.contains(&"sqs-python"));
+    assert!(python_names.contains(&"pubsub-python"));
+    assert!(python_names.contains(&"rabbit-python"));
+
+    let go_names: Vec<&'static str> = adapters_for(Lang::Go)
+        .iter()
+        .map(|a| a.name())
+        .collect();
+    assert!(go_names.contains(&"pubsub-go"));
+    assert!(go_names.contains(&"nats-go"));
+
+    let js_names: Vec<&'static str> = adapters_for(Lang::JavaScript)
+        .iter()
+        .map(|a| a.name())
+        .collect();
+    assert!(js_names.contains(&"sqs-node"));
+}
+
+// ── End-to-end Phase 20 acceptance via run_spec ───────────────────────────────
+//
+// Toolchain-gated.  Each language's run_spec block invokes the
+// dynamic runner on the fixture under tests/dynamic_fixtures/message_handler/
+// and asserts the differential verdict.  A missing toolchain triggers
+// a structured skip (eprintln + early return) — the test stays green
+// so the wider suite is not held hostage to a single host's missing
+// `python3` / `node` / `javac` / `go`.
+
+mod e2e_phase_20 {
+    use crate::common::fixture_harness::FIXTURE_LOCK;
+    use nyx_scanner::dynamic::runner::{run_spec, RunError, RunOutcome};
+    use nyx_scanner::dynamic::sandbox::SandboxOptions;
+    use nyx_scanner::dynamic::spec::{
+        default_toolchain_id, EntryKind, HarnessSpec, PayloadSlot, SpecDerivationStrategy,
+    };
+    use nyx_scanner::evidence::DifferentialVerdict;
+    use nyx_scanner::labels::Cap;
+    use nyx_scanner::symbol::Lang;
+    use std::path::PathBuf;
+    use std::process::Command;
+    use tempfile::TempDir;
+
+    fn command_available(bin: &str) -> bool {
+        Command::new(bin)
+            .arg("--version")
+            .output()
+            .map(|o| o.status.success())
+            .unwrap_or(false)
+    }
+
+    fn toolchain_for(lang: Lang) -> &'static str {
+        match lang {
+            Lang::Java => "java",
+            Lang::Python => "python3",
+            Lang::JavaScript | Lang::TypeScript => "node",
+            Lang::Go => "go",
+            _ => unreachable!("e2e_phase_20 only covers Java/Python/Node/Go"),
+        }
+    }
+
+    fn adapter_for(fixture_dir: &str) -> &'static str {
+        match fixture_dir {
+            "kafka_python" => "kafka-python",
+            "kafka_java" => "kafka-java",
+            "sqs_python" => "sqs-python",
+            "sqs_java" => "sqs-java",
+            "sqs_node" => "sqs-node",
+            "pubsub_python" => "pubsub-python",
+            "pubsub_go" => "pubsub-go",
+            "rabbit_python" => "rabbit-python",
+            "rabbit_java" => "rabbit-java",
+            "nats_go" => "nats-go",
+            other => panic!("unknown fixture_dir {other}"),
+        }
+    }
+
+    fn build_spec(
+        lang: Lang,
+        fixture_dir: &str,
+        fixture_file: &str,
+        handler: &str,
+        queue: &str,
+    ) -> (HarnessSpec, TempDir) {
+        let fixture_src = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("tests/dynamic_fixtures/message_handler")
+            .join(fixture_dir)
+            .join(fixture_file);
+        let tmp = TempDir::new().expect("create tempdir");
+        let dst = tmp.path().join(fixture_file);
+        std::fs::copy(&fixture_src, &dst).expect("copy fixture into tempdir");
+
+        let entry_file = dst.to_string_lossy().into_owned();
+        let mut digest = blake3::Hasher::new();
+        digest.update(b"phase20-e2e-message-handler|");
+        digest.update(fixture_dir.as_bytes());
+        digest.update(b"|");
+        digest.update(fixture_file.as_bytes());
+        let spec_hash = format!("{:016x}", {
+            let bytes = digest.finalize();
+            u64::from_le_bytes(bytes.as_bytes()[..8].try_into().unwrap())
+        });
+
+        if matches!(lang, Lang::Java) {
+            let workdir = std::path::PathBuf::from("/tmp/nyx-harness").join(&spec_hash);
+            let _ = std::fs::remove_dir_all(&workdir);
+        }
+
+        let adapter = adapter_for(fixture_dir);
+        let framework = Some(nyx_scanner::dynamic::framework::FrameworkBinding {
+            adapter: adapter.to_owned(),
+            kind: EntryKind::MessageHandler {
+                queue: queue.to_owned(),
+                message_schema: None,
+            },
+            route: None,
+            request_params: vec![],
+            response_writer: None,
+            middleware: vec![],
+        });
+
+        let spec = HarnessSpec {
+            finding_id: spec_hash.clone(),
+            entry_file: entry_file.clone(),
+            entry_name: handler.to_owned(),
+            entry_kind: EntryKind::MessageHandler {
+                queue: queue.to_owned(),
+                message_schema: None,
+            },
+            lang,
+            toolchain_id: default_toolchain_id(lang).into(),
+            payload_slot: PayloadSlot::Param(0),
+            expected_cap: Cap::CODE_EXEC,
+            constraint_hints: vec![],
+            sink_file: entry_file,
+            sink_line: 1,
+            spec_hash: spec_hash.clone(),
+            derivation: SpecDerivationStrategy::FromFlowSteps,
+            stubs_required: vec![],
+            framework,
+            java_toolchain: nyx_scanner::dynamic::spec::JavaToolchain::default(),
+        };
+
+        (spec, tmp)
+    }
+
+    fn run(
+        lang: Lang,
+        fixture_dir: &str,
+        fixture_file: &str,
+        handler: &str,
+        queue: &str,
+    ) -> Option<RunOutcome> {
+        let bin = toolchain_for(lang);
+        if !command_available(bin) {
+            eprintln!("SKIP {lang:?} {fixture_dir}/{fixture_file}: missing toolchain {bin}");
+            return None;
+        }
+        let _guard = FIXTURE_LOCK.lock().unwrap_or_else(|e| e.into_inner());
+        let (spec, _tmp) = build_spec(lang, fixture_dir, fixture_file, handler, queue);
+        let opts = SandboxOptions {
+            backend: nyx_scanner::dynamic::sandbox::SandboxBackend::Process,
+            ..SandboxOptions::default()
+        };
+        match run_spec(&spec, &opts) {
+            Ok(outcome) => Some(outcome),
+            Err(RunError::BuildFailed { stderr, attempts }) => {
+                eprintln!(
+                    "SKIP {lang:?} {fixture_dir}/{fixture_file}: harness build failed after {attempts} attempts: {stderr}",
+                );
+                None
+            }
+            Err(e) => panic!(
+                "run_spec({lang:?} {fixture_dir}/{fixture_file}) errored: {e:?}",
+            ),
+        }
+    }
+
+    /// Python kafka vuln must Confirm: the synthetic Kafka loopback
+    /// delivers `; echo NYX_PWN_CMDI` to the handler's `os.system`
+    /// which prints `NYX_PWN_CMDI` to stdout and the differential
+    /// oracle reads it.
+    #[test]
+    fn kafka_python_vuln_confirms_via_run_spec() {
+        let Some(outcome) = run(Lang::Python, "kafka_python", "vuln.py", "handler", "orders")
+        else {
+            return;
+        };
+        assert!(
+            outcome.triggered_by.is_some(),
+            "kafka-python MessageHandler vuln must Confirm via run_spec; got {outcome:?}",
+        );
+        let diff = outcome
+            .differential
+            .as_ref()
+            .expect("Confirmed run must carry a DifferentialOutcome");
+        assert_eq!(diff.verdict, DifferentialVerdict::Confirmed);
+    }
+
+    #[test]
+    fn sqs_python_vuln_confirms_via_run_spec() {
+        let Some(outcome) = run(Lang::Python, "sqs_python", "vuln.py", "handler", "jobs")
+        else {
+            return;
+        };
+        assert!(outcome.triggered_by.is_some());
+        let diff = outcome.differential.as_ref().expect("Confirmed");
+        assert_eq!(diff.verdict, DifferentialVerdict::Confirmed);
+    }
+
+    #[test]
+    fn pubsub_python_vuln_confirms_via_run_spec() {
+        let Some(outcome) = run(
+            Lang::Python,
+            "pubsub_python",
+            "vuln.py",
+            "callback",
+            "projects/p/subscriptions/s",
+        ) else {
+            return;
+        };
+        assert!(outcome.triggered_by.is_some());
+        let diff = outcome.differential.as_ref().expect("Confirmed");
+        assert_eq!(diff.verdict, DifferentialVerdict::Confirmed);
+    }
+
+    #[test]
+    fn rabbit_python_vuln_confirms_via_run_spec() {
+        let Some(outcome) = run(
+            Lang::Python,
+            "rabbit_python",
+            "vuln.py",
+            "on_message",
+            "work",
+        ) else {
+            return;
+        };
+        assert!(outcome.triggered_by.is_some());
+        let diff = outcome.differential.as_ref().expect("Confirmed");
+        assert_eq!(diff.verdict, DifferentialVerdict::Confirmed);
+    }
+
+    #[test]
+    fn sqs_node_vuln_confirms_via_run_spec() {
+        let Some(outcome) = run(Lang::JavaScript, "sqs_node", "vuln.js", "handler", "jobs")
+        else {
+            return;
+        };
+        assert!(
+            outcome.triggered_by.is_some(),
+            "sqs-node vuln failed; attempts: {:?}",
+            outcome.attempts,
+        );
+        let diff = outcome.differential.as_ref().expect("Confirmed");
+        assert_eq!(diff.verdict, DifferentialVerdict::Confirmed);
+    }
+}