go/zodb/*: Cosmetics

go/zodb/btree/btree.go

-// Copyright (C) 2018-2019  Nexedi SA and Contributors.
+// Copyright (C) 2018-2020  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 
 // Package btree provides B⁺ Trees for ZODB.
 //
-// It is modelled and data compatible with BTree/py package:
+// It is modelled after and is data compatible with BTree/py package:
 //
 //	http://btrees.readthedocs.io
 //	https://github.com/zopefoundation/BTrees
 //
 // A B⁺ tree consists of nodes. Only leaf tree nodes point to data.
-// Intermediate tree nodes contains keys and pointer to next-level tree nodes.
+// Intermediate tree nodes contains keys and pointers to next-level tree nodes.
 //
 // A well-balanced B⁺ tree always have uniform depth - that is the path to any
 // leaf node from the tree root is the same. However historically ZODB/py does

go/zodb/db.go

-// Copyright (C) 2018-2019  Nexedi SA and Contributors.
+// Copyright (C) 2018-2020  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -310,7 +310,7 @@ type hwaiter struct {
 //
 // Must be called db.mu released.
 func (db *DB) headWait(ctx context.Context, at Tid) (err error) {
-	defer xerr.Contextf(&err, "wait head ≥ %s", at)
+	defer xerr.Contextf(&err, "wait head ≥ @%s", at)
 
 	// precheck if db is already down -> error even if at is under coverage
 	if ready(db.down) {

go/zodb/δtail.go

-// Copyright (C) 2018-2019  Nexedi SA and Contributors.
+// Copyright (C) 2018-2020  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -118,7 +118,7 @@ func (δtail *ΔTail) Tail() Tid {
 //
 // Note: contrary to regular go slicing, low is exclusive while high is inclusive.
 func (δtail *ΔTail) SliceByRev(low, high Tid) /*readonly*/ []ΔRevEntry {
-	tail := δtail.Tail()
+	tail := δtail.tail
 	head := δtail.head
 	if !(tail <= low && low <= high && high <= head) {
 		panic(fmt.Sprintf("δtail.Slice: invalid query: (%s, %s];  (tail, head] = (%s, %s]", low, high, tail, head))