Reject userOps within 30 seconds of expiring (#175)

Author: hazim-j

.github/workflows/compliance.yml

@@ -31,8 +31,10 @@ jobs:
       - name: Checkout bundler spec test
         uses: actions/checkout@v3
         with:
-          repository: eth-infinitism/bundler-spec-tests
-          ref: 94a0634ebd6e6da657e863c134d20bc46724ed0f
+          # TODO: Revert back to eth-infinitism/bundler-spec-tests once
+          # https://github.com/eth-infinitism/bundler-spec-tests/pull/23 merged.
+          repository: hazim-j/bundler-spec-tests
+          ref: expires-too-soon-case
           path: ./bundler-spec-tests
           submodules: true
 

pkg/modules/checks/standalone.go

@@ -5,6 +5,7 @@ package checks
 import (
 	"math/big"
 	"sync"
+	"time"
 
 	"github.com/dgraph-io/badger/v3"
 	"github.com/ethereum/go-ethereum/common"
@@ -92,6 +93,14 @@ func (s *Standalone) SimulateOp() modules.UserOpHandlerFunc {
 					nil,
 				)
 			}
+			if sim.ReturnInfo.ValidUntil.Cmp(common.Big0) != 0 &&
+				time.Now().Unix() >= sim.ReturnInfo.ValidUntil.Int64()-30 {
+				return errors.NewRPCError(
+					errors.SHORT_DEADLINE,
+					"expires too soon",
+					nil,
+				)
+			}
 			return nil
 		})
 		g.Go(func() error {