Empty entry added when no padding at end of file

[mikenorgate]

I've run into an issue where an empty entry is added when reading a tar stream and I wanted to check if this was expected behaviour or not?

I have a scenario where this read operation

tar-split/tar/asm/disassemble.go

Line 130 in f966b14

n, err := outputRdr.Read(paddingChunk[:])

is retuning n=0 and err=EOF

In other places in this code you are checking that the length of the payload is greater than 0

tar-split/tar/asm/disassemble.go

Lines 57 to 66 in f966b14

	if b := tr.RawBytes(); len(b) > 0 {
	_, err := p.AddEntry(storage.Entry{
	Type: storage.SegmentType,
	Payload: b,
	})
	if err != nil {
	pW.CloseWithError(err)
	return
	}
	}

Should this length check also be applied when adding the padding chunk or is adding the empty entry desired?

[vbatts]

thanks for reporting. Do you have a reproducer for this situation?

[tianon]

Ooh, if this is what I think it is (the trailing "EOF" entry), then it might be useful to you that I just recently refactored the layer on tianon/true:oci to not include that (in case you need a very small test case).

[vbatts]

I just tried your layer from that tianon/true:oci image, but it passes right through this code and doesn't hit the issue.

diff --git a/tar/asm/assemble_test.go b/tar/asm/assemble_test.go
index 6cb7850..cfbcca6 100644
--- a/tar/asm/assemble_test.go
+++ b/tar/asm/assemble_test.go
@@ -140,6 +140,7 @@ var testCases = []struct {
        {"./testdata/iso-8859.tar.gz", "ddafa51cb03c74ec117ab366ee2240d13bba1ec3", 10240},
        {"./testdata/extranils.tar.gz", "e187b4b3e739deaccc257342f4940f34403dc588", 10648},
        {"./testdata/notenoughnils.tar.gz", "72f93f41efd95290baa5c174c234f5d4c22ce601", 512},
+       {"./testdata/1c51fc286aa95d9413226599576bafa38490b1e292375c90de095855b64caea6", "946caa03167a8cc707db6ff9785608b652e631dc", 1024},
 }

 func TestTarStream(t *testing.T) {