From f3113f78b77662bd566f8382d426fda4213456bc Mon Sep 17 00:00:00 2001
From: lukechampine <luke.champine@gmail.com>
Date: Wed, 31 Jul 2019 17:32:14 -0400
Subject: [PATCH] merkle: Mark all trimmed sectors as changed

---
 merkle/proof.go         | 11 ++++++-----
 renter/proto/session.go |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/merkle/proof.go b/merkle/proof.go
index 7010ba6..4119ac8 100644
--- a/merkle/proof.go
+++ b/merkle/proof.go
@@ -225,8 +225,10 @@ func sectorsChanged(actions []renterhost.RPCWriteAction, numSectors int) []int {
 			newNumSectors++
 
 		case renterhost.RPCWriteActionTrim:
-			newNumSectors -= int(action.A)
-			sectorsChanged[newNumSectors] = struct{}{}
+			for i := 0; i < int(action.A); i++ {
+				newNumSectors--
+				sectorsChanged[newNumSectors] = struct{}{}
+			}
 
 		case renterhost.RPCWriteActionSwap:
 			sectorsChanged[int(action.A)] = struct{}{}
@@ -328,9 +330,8 @@ func modifyProofRanges(proofIndices []int, actions []renterhost.RPCWriteAction,
 			numSectors++
 
 		case renterhost.RPCWriteActionTrim:
-			n := int(action.A)
-			proofIndices = proofIndices[:len(proofIndices)-n]
-			numSectors -= n
+			proofIndices = proofIndices[:len(proofIndices)-int(action.A)]
+			numSectors -= int(action.A)
 
 		case renterhost.RPCWriteActionSwap:
 		case renterhost.RPCWriteActionUpdate:
diff --git a/renter/proto/session.go b/renter/proto/session.go
index ce79200..c94ea1d 100644
--- a/renter/proto/session.go
+++ b/renter/proto/session.go
@@ -343,7 +343,7 @@ func (s *Session) Write(actions []renterhost.RPCWriteAction) (err error) {
 	leafHashes := merkleResp.OldLeafHashes
 	oldRoot, newRoot := rev.NewFileMerkleRoot, merkleResp.NewMerkleRoot
 	if !merkle.VerifyDiffProof(actions, numSectors, proofHashes, leafHashes, oldRoot, newRoot) {
-		err := errors.New("invalid Merkle proof for old root")
+		err := errors.New("invalid Merkle proof")
 		s.sess.WriteResponse(nil, err)
 		return err
 	}