Bugfix: don't try to cull connections from an empty pool.

The first step in culling connections was to take a subset of the pool's
connections from index 0 to numToCull. This leads to an error if
numToCull is also zero.

fiber_orm.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version       = "1.0.1"
+version       = "1.0.2"
 author        = "Jonathan Bernard"
 description   = "Lightweight Postgres ORM for Nim."
 license       = "GPL-3.0"

src/fiber_orm/pool.nim

@@ -62,6 +62,8 @@ proc maintain(pool: DbConnPool): void =
   let freeConns = pool.conns.filterIt(it.free)
   if pool.conns.len > pool.cfg.poolSize and freeConns.len > 0:
     let numToCull = min(freeConns.len, pool.conns.len - pool.cfg.poolSize)
+
+    if numToCull > 0:
       let toCull = freeConns[0..numToCull]
       pool.conns.keepIf((pc) => toCull.allIt(it.id != pc.id))
       for culled in toCull:
@@ -93,5 +95,5 @@ proc release*(pool: DbConnPool, connId: int): void =
 
 template withConn*(pool: DbConnPool, stmt: untyped): untyped =
   let (connId, conn {.inject.}) = take(pool)
-  stmt
-  release(pool, connId)
+  try: stmt
+  finally: release(pool, connId)