store/tikv: support injecting customized failure to prewrite (#23432)

store/tikv/prewrite.go

@@ -126,27 +126,25 @@ func (action actionPrewrite) handleSingleBatch(c *twoPhaseCommitter, bo *Backoff
 	// checked there.
 
 	if c.sessionID > 0 {
-		failpoint.Inject("beforePrewrite", func() {})
-
-		failpoint.Inject("prewritePrimaryFail", func() {
-			if batch.isPrimary {
+		if batch.isPrimary {
+			failpoint.Inject("prewritePrimaryFail", func() {
 				// Delay to avoid cancelling other normally ongoing prewrite requests.
 				time.Sleep(time.Millisecond * 50)
 				logutil.Logger(bo.ctx).Info("[failpoint] injected error on prewriting primary batch",
 					zap.Uint64("txnStartTS", c.startTS))
 				failpoint.Return(errors.New("injected error on prewriting primary batch"))
-			}
-		})
-
-		failpoint.Inject("prewriteSecondaryFail", func() {
-			if !batch.isPrimary {
+			})
+			failpoint.Inject("prewritePrimary", nil) // for other failures like sleep or pause
+		} else {
+			failpoint.Inject("prewriteSecondaryFail", func() {
 				// Delay to avoid cancelling other normally ongoing prewrite requests.
 				time.Sleep(time.Millisecond * 50)
 				logutil.Logger(bo.ctx).Info("[failpoint] injected error on prewriting secondary batch",
 					zap.Uint64("txnStartTS", c.startTS))
 				failpoint.Return(errors.New("injected error on prewriting secondary batch"))
-			}
-		})
+			})
+			failpoint.Inject("prewriteSecondary", nil) // for other failures like sleep or pause
+		}
 	}
 
 	txnSize := uint64(c.regionTxnSize[batch.region.id])