sync: update misleading comment in map.go about entry type

As discussed in: https://github.com/golang/go/issues/45429,  about entry
type comments, it is possible for p == nil when m.dirty != nil, so
update the commemt about it.

Fixes #45429

Change-Id: I7ef96ee5b6948df9ac736481d177a59ab66d7d4d
GitHub-Last-Rev: 202c598a0ab98f4634cb56fe2486e8e82f9d991f
GitHub-Pull-Request: golang/go#45443
Reviewed-on: https://go-review.googlesource.com/c/go/+/308292
Reviewed-by: Changkun Ou <euryugasaki@gmail.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Trust: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

diff --git a/src/sync/map.go b/src/sync/map.go
index 9ad25353ff48cef7c541de24e3382c346dc44f61..dfb62dd3e801cc8717ab7791b0a0e31f4ec43a1c 100644 (file)
--- a/src/sync/map.go
+++ b/src/sync/map.go
@@ -73,7 +73,8 @@ var expunged = unsafe.Pointer(new(interface{}))
 type entry struct {
        // p points to the interface{} value stored for the entry.
        //
-       // If p == nil, the entry has been deleted and m.dirty == nil.
+       // If p == nil, the entry has been deleted, and either m.dirty == nil or
+       // m.dirty[key] is e.
        //
        // If p == expunged, the entry has been deleted, m.dirty != nil, and the entry
        // is missing from m.dirty.