From 41c59b77fd7a96fdb929ed3f004d92a7ad1b3946 Mon Sep 17 00:00:00 2001
From: hphamMolecula <89804723+hphamMolecula@users.noreply.github.com>
Date: Mon, 18 Jul 2022 17:35:34 -0500
Subject: [PATCH] FB-1548 - Added a fix for panic error that could happen when
 a view is opened by the ingest process but at the same time, was also deleted
 by TTL (#2147)

---
 field.go           |  4 +++-
 roaring/roaring.go |  3 +++
 view.go            | 13 +++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/field.go b/field.go
index d2bd17223..0927146d4 100644
--- a/field.go
+++ b/field.go
@@ -1110,7 +1110,7 @@ func (f *Field) createViewIfNotExistsBase(cvm *CreateViewMessage) (*view, bool,
 
 	// If we already have this view, we can probably assume etcd already
 	// has it.
-	if view := f.viewMap[cvm.View]; view != nil {
+	if view := f.viewMap[cvm.View]; view != nil && !view.isClosing() {
 		return view, false, nil
 	}
 
@@ -1142,6 +1142,8 @@ func (f *Field) newView(path, name string) *view {
 
 // deleteView removes the view from the field.
 func (f *Field) deleteView(name string) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
 	view := f.viewMap[name]
 	if view == nil {
 		return ErrInvalidView
diff --git a/roaring/roaring.go b/roaring/roaring.go
index 78071f505..4d9079d5b 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -444,6 +444,9 @@ func (b *Bitmap) DirectAdd(v uint64) bool {
 
 // Contains returns true if v is in the bitmap.
 func (b *Bitmap) Contains(v uint64) bool {
+	if b == nil {
+		return false
+	}
 	c := b.Containers.Get(highbits(v))
 	if c == nil {
 		return false
diff --git a/view.go b/view.go
index 331ef714a..36fa0ba82 100644
--- a/view.go
+++ b/view.go
@@ -331,11 +331,24 @@ func (v *view) Name() string {
 	return v.name
 }
 
+func (v *view) isClosing() bool {
+	select {
+	case <-v.closing:
+		return true
+	default:
+		return false
+	}
+}
+
 // CreateFragmentIfNotExists returns a fragment in the view by shard.
 func (v *view) CreateFragmentIfNotExists(shard uint64) (*fragment, error) {
 	v.mu.Lock()
 	defer v.mu.Unlock()
 
+	if v.isClosing() {
+		return nil, fmt.Errorf("cannot create fragment, view is closed")
+	}
+
 	// Find fragment in cache first.
 	if frag := v.fragments[shard]; frag != nil {
 		return frag, nil