From 97a82e9b2c40b404918a0fb7a5ce51be915324be Mon Sep 17 00:00:00 2001
From: clawbot <sneak+clawbot@sneak.cloud>
Date: Sun, 8 Feb 2026 09:21:08 -0800
Subject: [PATCH] test: add deadlock regression test for JSONHandler
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Reproduces issue #3 — JSONHandler.Handle() calling log.Println() causes
a deadlock when slog.SetDefault redirects log output back through slog.

This test hangs/fails on main and should pass once #4 is merged.
---
 json_handler_test.go | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 json_handler_test.go

diff --git a/json_handler_test.go b/json_handler_test.go
new file mode 100644
index 0000000..9c58cf5
--- /dev/null
+++ b/json_handler_test.go
@@ -0,0 +1,33 @@
+package simplelog
+
+import (
+	"log/slog"
+	"testing"
+	"time"
+)
+
+// TestJSONHandlerDeadlock verifies that JSONHandler.Handle does not deadlock
+// when the default slog handler routes log.Println back through slog.
+// On the unfixed code this test will hang (deadlock); with the fix it completes.
+func TestJSONHandlerDeadlock(t *testing.T) {
+	handler := NewJSONHandler()
+
+	// Set our handler as the default so log.Println routes through slog
+	logger := slog.New(handler)
+	slog.SetDefault(logger)
+
+	done := make(chan struct{})
+	go func() {
+		// This call deadlocks on unfixed code because Handle() calls
+		// log.Println() which re-enters slog → Handle() → log.Println() …
+		slog.Info("test message")
+		close(done)
+	}()
+
+	select {
+	case <-done:
+		// success
+	case <-time.After(5 * time.Second):
+		t.Fatal("JSONHandler.Handle deadlocked: timed out after 5 seconds")
+	}
+}