Introducing InitiatingFlow annotation which has to be annotated by initiating flows.

This removes the need for the shareParentSessions parameter of FlowLogic.subFlow. It also has the flow's version number so FlowVersion is now no longer needed.

samples/trader-demo/src/main/kotlin/net/corda/traderdemo/flow/BuyerFlow.kt

@@ -49,7 +49,7 @@ class BuyerFlow(val otherParty: Party,
                 CommercialPaper.State::class.java)
 
         // This invokes the trading flow and out pops our finished transaction.
-        val tradeTX: SignedTransaction = subFlow(buyer, shareParentSessions = true)
+        val tradeTX: SignedTransaction = subFlow(buyer)
         // TODO: This should be moved into the flow itself.
         serviceHub.recordTransactions(listOf(tradeTX))
 

samples/trader-demo/src/main/kotlin/net/corda/traderdemo/flow/SellerFlow.kt

@@ -9,10 +9,10 @@ import net.corda.core.crypto.SecureHash
 import net.corda.core.crypto.generateKeyPair
 import net.corda.core.days
 import net.corda.core.flows.FlowLogic
+import net.corda.core.flows.InitiatingFlow
 import net.corda.core.node.NodeInfo
 import net.corda.core.seconds
 import net.corda.core.transactions.SignedTransaction
-import net.corda.core.utilities.DUMMY_BANK_C
 import net.corda.core.utilities.ProgressTracker
 import net.corda.flows.NotaryFlow
 import net.corda.flows.TwoPartyTradeFlow
@@ -21,6 +21,7 @@ import java.security.PublicKey
 import java.time.Instant
 import java.util.*
 
+@InitiatingFlow
 class SellerFlow(val otherParty: Party,
                  val amount: Amount<Currency>,
                  override val progressTracker: ProgressTracker) : FlowLogic<SignedTransaction>() {
@@ -60,7 +61,7 @@ class SellerFlow(val otherParty: Party,
                 amount,
                 cpOwnerKey,
                 progressTracker.getChildProgressTracker(TRADING)!!)
-        return subFlow(seller, shareParentSessions = true)
+        return subFlow(seller)
     }
 
     @Suspendable