R80: req secret for introspection, pool conn on panic

internal/cache/backends/review_r80_test.go

@@ -0,0 +1,48 @@
+package backends
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+)
+
+// TestExecuteWithRetry_ReturnsConnOnPanic is a regression: executeWithRetry
+// returned the borrowed connection imperatively with no defer, so an operation
+// panic leaked the Redis connection out of the pool and desynced its counters.
+// The fix guarantees the connection is returned on all exit paths including
+// panic.
+func TestExecuteWithRetry_ReturnsConnOnPanic(t *testing.T) {
+	pool, err := NewConnectionPool(&PoolConfig{MaxConnections: 1, ConnectTimeout: 50 * time.Millisecond})
+	if err != nil {
+		t.Fatalf("NewConnectionPool: %v", err)
+	}
+
+	// Seed one available connection so executeWithRetry's Get succeeds without
+	// dialing (no Redis server needed).
+	pc, sw := net.Pipe()
+	defer sw.Close()
+	rc := &RedisConn{conn: pc, readTimeout: time.Second, writeTimeout: time.Second}
+	pool.Put(rc)
+
+	if got := len(pool.connections); got != 1 {
+		t.Fatalf("setup: expected one seeded connection, got %d", got)
+	}
+
+	r := &RedisBackend{pool: pool}
+
+	func() {
+		defer func() {
+			if v := recover(); v == nil {
+				t.Fatalf("expected operation to panic")
+			}
+		}()
+		_ = r.executeWithRetry(context.Background(), func(c *RedisConn) error {
+			panic("boom")
+		})
+	}()
+
+	if got := len(pool.connections); got != 1 {
+		t.Fatalf("expected connection returned to pool after operation panic, got %d", got)
+	}
+}