Update go-memdb

To use a version that will not panic when an iterator is used with modifications.

go.mod

@@ -37,7 +37,7 @@ require (
 	github.com/hashicorp/go-connlimit v0.3.0
 	github.com/hashicorp/go-discover v0.0.0-20200501174627-ad1e96bde088
 	github.com/hashicorp/go-hclog v0.14.1
-	github.com/hashicorp/go-memdb v1.3.0
+	github.com/hashicorp/go-memdb v1.3.1
 	github.com/hashicorp/go-msgpack v0.5.5
 	github.com/hashicorp/go-multierror v1.1.0
 	github.com/hashicorp/go-raftchunking v0.6.1

go.sum

@@ -240,8 +240,8 @@ github.com/hashicorp/go-immutable-radix v1.0.0/go.mod h1:0y9vanUI8NX6FsYoO3zeMjh
 github.com/hashicorp/go-immutable-radix v1.3.0 h1:8exGP7ego3OmkfksihtSouGMZ+hQrhxx+FVELeXpVPE=
 github.com/hashicorp/go-immutable-radix v1.3.0/go.mod h1:0y9vanUI8NX6FsYoO3zeMjhV/C5i9g4Q3DwcSNZ4P60=
 github.com/hashicorp/go-kms-wrapping/entropy v0.1.0/go.mod h1:d1g9WGtAunDNpek8jUIEJnBlbgKS1N2Q61QkHiZyR1g=
-github.com/hashicorp/go-memdb v1.3.0 h1:xdXq34gBOMEloa9rlGStLxmfX/dyIK8htOv36dQUwHU=
-github.com/hashicorp/go-memdb v1.3.0/go.mod h1:Mluclgwib3R93Hk5fxEfiRhB+6Dar64wWh71LpNSe3g=
+github.com/hashicorp/go-memdb v1.3.1 h1:EIj6L28rTL41BDHBvwq1VJXzcmY2R2JBrxpWxF7Etyk=
+github.com/hashicorp/go-memdb v1.3.1/go.mod h1:Mluclgwib3R93Hk5fxEfiRhB+6Dar64wWh71LpNSe3g=
 github.com/hashicorp/go-msgpack v0.5.3/go.mod h1:ahLV/dePpqEmjfWmKiqvPkv/twdG7iPBM1vqhUKIvfM=
 github.com/hashicorp/go-msgpack v0.5.5 h1:i9R9JSrqIz0QVLz3sz+i3YJdT7TTSLcfLLzJi9aZTuI=
 github.com/hashicorp/go-msgpack v0.5.5/go.mod h1:ahLV/dePpqEmjfWmKiqvPkv/twdG7iPBM1vqhUKIvfM=

vendor/github.com/hashicorp/go-memdb/filter.go

@@ -13,17 +13,22 @@ type FilterIterator struct {
 	iter ResultIterator
 }
 
-func NewFilterIterator(wrap ResultIterator, filter FilterFunc) *FilterIterator {
+// NewFilterIterator wraps a ResultIterator. The filter function is applied
+// to each value returned by a call to iter.Next.
+//
+// See the documentation for ResultIterator to understand the behaviour of the
+// returned FilterIterator.
+func NewFilterIterator(iter ResultIterator, filter FilterFunc) *FilterIterator {
 	return &FilterIterator{
 		filter: filter,
-		iter:   wrap,
+		iter:   iter,
 	}
 }
 
 // WatchCh returns the watch channel of the wrapped iterator.
 func (f *FilterIterator) WatchCh() <-chan struct{} { return f.iter.WatchCh() }
 
-// Next returns the next non-filtered result from the wrapped iterator
+// Next returns the next non-filtered result from the wrapped iterator.
 func (f *FilterIterator) Next() interface{} {
 	for {
 		if value := f.iter.Next(); value == nil || !f.filter(value) {

vendor/github.com/hashicorp/go-memdb/txn.go

@@ -52,16 +52,16 @@ func (txn *Txn) TrackChanges() {
 	}
 }
 
-// readableIndex returns a transaction usable for reading the given
-// index in a table. If a write transaction is in progress, we may need
-// to use an existing modified txn.
+// readableIndex returns a transaction usable for reading the given index in a
+// table. If the transaction is a write transaction with modifications, a clone of the
+// modified index will be returned.
 func (txn *Txn) readableIndex(table, index string) *iradix.Txn {
 	// Look for existing transaction
 	if txn.write && txn.modified != nil {
 		key := tableIndex{table, index}
 		exist, ok := txn.modified[key]
 		if ok {
-			return exist
+			return exist.Clone()
 		}
 	}
 
@@ -663,15 +663,35 @@ func (txn *Txn) getIndexValue(table, index string, args ...interface{}) (*IndexS
 	return indexSchema, val, err
 }
 
-// ResultIterator is used to iterate over a list of results
-// from a Get query on a table.
+// ResultIterator is used to iterate over a list of results from a query on a table.
+//
+// When a ResultIterator is created from a write transaction, the results from
+// Next will reflect a snapshot of the table at the time the ResultIterator is
+// created.
+// This means that calling Insert or Delete on a transaction while iterating is
+// allowed, but the changes made by Insert or Delete will not be observed in the
+// results returned from subsequent calls to Next. For example if an item is deleted
+// from the index used by the iterator it will still be returned by Next. If an
+// item is inserted into the index used by the iterator, it will not be returned
+// by Next. However, an iterator created after a call to Insert or Delete will
+// reflect the modifications.
+//
+// When a ResultIterator is created from a write transaction, and there are already
+// modifications to the index used by the iterator, the modification cache of the
+// index will be invalidated. This may result in some additional allocations if
+// the same node in the index is modified again.
 type ResultIterator interface {
 	WatchCh() <-chan struct{}
+	// Next returns the next result from the iterator. If there are no more results
+	// nil is returned.
 	Next() interface{}
 }
 
-// Get is used to construct a ResultIterator over all the
-// rows that match the given constraints of an index.
+// Get is used to construct a ResultIterator over all the rows that match the
+// given constraints of an index.
+//
+// See the documentation for ResultIterator to understand the behaviour of the
+// returned ResultIterator.
 func (txn *Txn) Get(table, index string, args ...interface{}) (ResultIterator, error) {
 	indexIter, val, err := txn.getIndexIterator(table, index, args...)
 	if err != nil {
@@ -691,7 +711,10 @@ func (txn *Txn) Get(table, index string, args ...interface{}) (ResultIterator, e
 
 // GetReverse is used to construct a Reverse ResultIterator over all the
 // rows that match the given constraints of an index.
-// The returned ResultIterator's Next() will return the next Previous value
+// The returned ResultIterator's Next() will return the next Previous value.
+//
+// See the documentation for ResultIterator to understand the behaviour of the
+// returned ResultIterator.
 func (txn *Txn) GetReverse(table, index string, args ...interface{}) (ResultIterator, error) {
 	indexIter, val, err := txn.getIndexIteratorReverse(table, index, args...)
 	if err != nil {
@@ -715,6 +738,9 @@ func (txn *Txn) GetReverse(table, index string, args ...interface{}) (ResultIter
 // range scans within an index. It is not possible to watch the resulting
 // iterator since the radix tree doesn't efficiently allow watching on lower
 // bound changes. The WatchCh returned will be nill and so will block forever.
+//
+// See the documentation for ResultIterator to understand the behaviour of the
+// returned ResultIterator.
 func (txn *Txn) LowerBound(table, index string, args ...interface{}) (ResultIterator, error) {
 	indexIter, val, err := txn.getIndexIterator(table, index, args...)
 	if err != nil {
@@ -738,6 +764,9 @@ func (txn *Txn) LowerBound(table, index string, args ...interface{}) (ResultIter
 // resulting iterator since the radix tree doesn't efficiently allow watching
 // on lower bound changes. The WatchCh returned will be nill and so will block
 // forever.
+//
+// See the documentation for ResultIterator to understand the behaviour of the
+// returned ResultIterator.
 func (txn *Txn) ReverseLowerBound(table, index string, args ...interface{}) (ResultIterator, error) {
 	indexIter, val, err := txn.getIndexIteratorReverse(table, index, args...)
 	if err != nil {
@@ -850,7 +879,7 @@ func (txn *Txn) getIndexIterator(table, index string, args ...interface{}) (*ira
 	indexTxn := txn.readableIndex(table, indexSchema.Name)
 	indexRoot := indexTxn.Root()
 
-	// Get an interator over the index
+	// Get an iterator over the index
 	indexIter := indexRoot.Iterator()
 	return indexIter, val, nil
 }

vendor/modules.txt

@@ -231,7 +231,7 @@ github.com/hashicorp/go-discover/provider/vsphere
 github.com/hashicorp/go-hclog
 # github.com/hashicorp/go-immutable-radix v1.3.0
 github.com/hashicorp/go-immutable-radix
-# github.com/hashicorp/go-memdb v1.3.0
+# github.com/hashicorp/go-memdb v1.3.1
 github.com/hashicorp/go-memdb
 # github.com/hashicorp/go-msgpack v0.5.5
 github.com/hashicorp/go-msgpack/codec