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       = "1.0.0"
+version       = "1.0.2"
 author        = "Jonathan Bernard"
 description   = "Lightweight Postgres ORM for Nim."
 license       = "GPL-3.0"

src/fiber_orm.nim

@@ -34,13 +34,11 @@ proc createRecord*[T](db: DbConn, rec: T): T =
   var mc = newMutateClauses()
   populateMutateClauses(rec, true, mc)
 
-  # Confusingly, getRow allows inserts and updates. We use it to get back the ID
-  # we want from the row.
   let sqlStmt =
     "INSERT INTO " & tableName(rec) &
     " (" & mc.columns.join(",") & ") " &
     " VALUES (" & mc.placeholders.join(",") & ") " &
-    " RETURNING *"
+    " RETURNING " & columnNamesForModel(rec).join(",")
 
   log().debug "createRecord: [" & sqlStmt & "]"
   let newRow = db.getRow(sql(sqlStmt), mc.values)

src/fiber_orm/pool.nim

@@ -62,14 +62,16 @@ 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)
-    let toCull = freeConns[0..numToCull]
-    pool.conns.keepIf((pc) => toCull.allIt(it.id != pc.id))
-    for culled in toCull:
-      try: culled.conn.close()
-      except: discard ""
-    log().debug(
-      "Trimming pool size. Culled $# free connections. $# connections remaining." %
-      [$toCull.len, $pool.conns.len])
+
+    if numToCull > 0:
+      let toCull = freeConns[0..numToCull]
+      pool.conns.keepIf((pc) => toCull.allIt(it.id != pc.id))
+      for culled in toCull:
+        try: culled.conn.close()
+        except: discard ""
+      log().debug(
+        "Trimming pool size. Culled $# free connections. $# connections remaining." %
+        [$toCull.len, $pool.conns.len])
 
 proc take*(pool: DbConnPool): tuple[id: int, conn: DbConn] =
   pool.maintain
@@ -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)