From 00be2bf18d94172729760db8519d8e6299036a53 Mon Sep 17 00:00:00 2001
From: Audrius Butkevicius <audrius.butkevicius@gmail.com>
Date: Sun, 22 May 2016 10:16:09 +0000
Subject: [PATCH] lib/model: Track puller creation times (fixes #3145)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3150
---
 lib/model/progressemitter_test.go | 12 ++++++++++++
 lib/model/rwfolder.go             |  1 +
 lib/model/sentdownloadstate.go    | 10 +++++++---
 lib/model/sharedpullerstate.go    |  1 +
 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/lib/model/progressemitter_test.go b/lib/model/progressemitter_test.go
index bb20c2248..2cabc42ac 100644
--- a/lib/model/progressemitter_test.go
+++ b/lib/model/progressemitter_test.go
@@ -245,6 +245,18 @@ func TestSendDownloadProgressMessages(t *testing.T) {
 	expect(1, state1, protocol.UpdateTypeAppend, v2, []int32{1, 2}, true)
 	expectEmpty()
 
+	// Returns forget and append if sharedPullerState creation timer changes.
+
+	state1.available = []int32{1}
+	state1.availableUpdated = tick()
+	state1.created = tick()
+
+	p.sendDownloadProgressMessages()
+
+	expect(0, state1, protocol.UpdateTypeForget, v2, nil, false)
+	expect(1, state1, protocol.UpdateTypeAppend, v2, []int32{1}, true)
+	expectEmpty()
+
 	// Sends an empty update if new file exists, but does not have any blocks yet. (To indicate that the old blocks are no longer available)
 	state1.file.Version = v1
 	state1.available = nil
diff --git a/lib/model/rwfolder.go b/lib/model/rwfolder.go
index 01d4d38c7..5c991e521 100644
--- a/lib/model/rwfolder.go
+++ b/lib/model/rwfolder.go
@@ -1011,6 +1011,7 @@ func (f *rwFolder) handleFile(file protocol.FileInfo, copyChan chan<- copyBlocks
 		version:          curFile.Version,
 		mut:              sync.NewRWMutex(),
 		sparse:           f.allowSparse,
+		created:          time.Now(),
 	}
 
 	l.Debugf("%v need file %s; copy %d, reused %v", f, file.Name, len(blocks), reused)
diff --git a/lib/model/sentdownloadstate.go b/lib/model/sentdownloadstate.go
index 9fd50b0bb..8d5a9b543 100644
--- a/lib/model/sentdownloadstate.go
+++ b/lib/model/sentdownloadstate.go
@@ -18,6 +18,7 @@ type sentFolderFileDownloadState struct {
 	blockIndexes []int32
 	version      protocol.Vector
 	updated      time.Time
+	created      time.Time
 }
 
 // sentFolderDownloadState represents a state of what we've announced as available
@@ -41,6 +42,7 @@ func (s *sentFolderDownloadState) update(pullers []*sharedPullerState) []protoco
 		pullerBlockIndexes := puller.Available()
 		pullerVersion := puller.file.Version
 		pullerBlockIndexesUpdated := puller.AvailableUpdated()
+		pullerCreated := puller.created
 
 		localFile, ok := s.files[name]
 
@@ -52,6 +54,7 @@ func (s *sentFolderDownloadState) update(pullers []*sharedPullerState) []protoco
 					blockIndexes: pullerBlockIndexes,
 					updated:      pullerBlockIndexesUpdated,
 					version:      pullerVersion,
+					created:      pullerCreated,
 				}
 
 				updates = append(updates, protocol.FileDownloadProgressUpdate{
@@ -70,9 +73,9 @@ func (s *sentFolderDownloadState) update(pullers []*sharedPullerState) []protoco
 			continue
 		}
 
-		if !pullerVersion.Equal(localFile.version) {
-			// The version has changed, clean up whatever we had for the old
-			// file, and advertise the new file.
+		if !pullerVersion.Equal(localFile.version) || !pullerCreated.Equal(localFile.created) {
+			// The version has changed or the puller was reconstrcuted due to failure.
+			// Clean up whatever we had for the old file, and advertise the new file.
 			updates = append(updates, protocol.FileDownloadProgressUpdate{
 				Name:       name,
 				Version:    localFile.version,
@@ -87,6 +90,7 @@ func (s *sentFolderDownloadState) update(pullers []*sharedPullerState) []protoco
 			localFile.blockIndexes = pullerBlockIndexes
 			localFile.updated = pullerBlockIndexesUpdated
 			localFile.version = pullerVersion
+			localFile.created = pullerCreated
 			continue
 		}
 
diff --git a/lib/model/sharedpullerstate.go b/lib/model/sharedpullerstate.go
index eabcbd3e1..a36b6d42e 100644
--- a/lib/model/sharedpullerstate.go
+++ b/lib/model/sharedpullerstate.go
@@ -29,6 +29,7 @@ type sharedPullerState struct {
 	ignorePerms bool
 	version     protocol.Vector // The current (old) version
 	sparse      bool
+	created     time.Time
 
 	// Mutable, must be locked for access
 	err              error        // The first error we hit