archive/tar: document how Reader.Read handles header-only files

Commit dd5e14a ensured that no data could be read for header-only files regardless of what the Header.Size said. We should document this fact in Reader.Read. Updates golang#13647 Change-Id: I4df9a2892bc66b49e0279693d08454bf696cfa31 Reviewed-on: https://go-review.googlesource.com/17913 Reviewed-by: Russ Cox <[email protected]>
ribrdb · Dec 17, 2015 · 7a2913c · 7a2913c
1 parent 5c0629b
commit 7a2913c
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
@@ -857,6 +857,10 @@ func (tr *Reader) numBytes() int64 {
 // Read reads from the current entry in the tar archive.
 // It returns 0, io.EOF when it reaches the end of that entry,
 // until Next is called to advance to the next entry.
+//
+// Calling Read on special types like TypeLink, TypeSymLink, TypeChar,
+// TypeBlock, TypeDir, and TypeFifo returns 0, io.EOF regardless of what
+// the Header.Size claims.
 func (tr *Reader) Read(b []byte) (n int, err error) {
 	if tr.err != nil {
 		return 0, tr.err