[COMPRESS-510] Multiple retrievals of InputStream for same SevenZFile entry fails

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.20
• Fix Version/s: 1.21
• Assignee: Peter Lee
• Reporter: Robin Schimpf
• Created: 17/Apr/20 08:09
• Updated: 07/Mar/21 15:03
• Resolved: 07/Mar/21 15:03

Description

I was trying out the new random access for the 7z files and have one of our tests failing where we are trying to read the same entry multiple times without closing the archive.

Reproducing test case (I added this locally to the SevenZFileTest class)

@Test
public void retrieveInputStreamForEntryMultipleTimes() throws IOException {
    try (SevenZFile sevenZFile = new SevenZFile(getFile("bla.7z"))) {
        for (SevenZArchiveEntry entry : sevenZFile.getEntries()) {
            byte[] firstRead = IOUtils.toByteArray(sevenZFile.getInputStream(entry));
            byte[] secondRead = IOUtils.toByteArray(sevenZFile.getInputStream(entry));
            assertArrayEquals(firstRead, secondRead);
        }
    }
}

The Exception thrown is

java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 2	at org.apache.commons.compress.archivers.sevenz.SevenZFile.buildDecodingStream(SevenZFile.java:1183)
	at org.apache.commons.compress.archivers.sevenz.SevenZFile.getInputStream(SevenZFile.java:1436)
	at org.apache.commons.compress.archivers.sevenz.SevenZFileTest.retrieveInputStreamForEntryMultipleTimes(SevenZFileTest.java:688)
	...

A similar test case for e.g. zip works fine

@Test
public void retrieveInputStreamForEntryMultipleTimes() throws IOException {
    try (ZipFile zipFile = new ZipFile(getFile("bla.zip"))) {
        Enumeration<ZipArchiveEntry> entry = zipFile.getEntries();
        while (entry.hasMoreElements()) {
            ZipArchiveEntry e = entry.nextElement();
            byte[] firstRead = IOUtils.toByteArray(zipFile.getInputStream(e));
            byte[] secondRead = IOUtils.toByteArray(zipFile.getInputStream(e));
            assertArrayEquals(firstRead, secondRead);
        }
    }
}