indexer-cli throws java.nio.file.FileAlreadyExistsException on re-run with same index dir

[tobias]

Affected version

7.1.6

Bug description

When running the CLI with:

java -jar indexer-cli-7.1.6-cli.jar \
    --name clojars \
    --type min \
    --index ./index \
    --destination ./repo/.index \
    --repository ./repo \
    --checksums \
    --quiet \
    --chunks \
    --keep 50

It runs successfully on the first run (when ./index is empty). On a subsequent run, it fails with:

java.io.IOException: Error scanning context clojars: java.nio.file.FileAlreadyExistsException: /tmp/clojars-tmp10757666929368582455/nexus-maven-repository-index-packer.properties
        at org.apache.maven.index.DefaultNexusIndexer.scan(DefaultNexusIndexer.java:313)
        at org.apache.maven.index.DefaultNexusIndexer.scan(DefaultNexusIndexer.java:258)
        at org.apache.maven.index.cli.NexusIndexerCli.index(NexusIndexerCli.java:448)
        at org.apache.maven.index.cli.NexusIndexerCli.execute(NexusIndexerCli.java:164)
        at org.apache.maven.index.cli.NexusIndexerCli.main(NexusIndexerCli.java:116)
Caused by: java.nio.file.FileAlreadyExistsException: /tmp/clojars-tmp10757666929368582455/nexus-maven-repository-index-packer.properties
        at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:94)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
        at java.base/sun.nio.fs.UnixFileSystemProvider.newFileChannel(UnixFileSystemProvider.java:213)
        at java.base/sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:244)
        at java.base/java.nio.file.spi.FileSystemProvider.newOutputStream(FileSystemProvider.java:426)
        at java.base/java.nio.file.Files.newOutputStream(Files.java:215)
        at org.apache.lucene.store.FSDirectory$FSIndexOutput.<init>(FSDirectory.java:394)
        at org.apache.lucene.store.FSDirectory$FSIndexOutput.<init>(FSDirectory.java:387)
        at org.apache.lucene.store.FSDirectory.createOutput(FSDirectory.java:220)
        at org.apache.lucene.store.Directory.copyFrom(Directory.java:181)
        at org.apache.maven.index.context.IndexUtils.copyFile(IndexUtils.java:73)
        at org.apache.maven.index.context.IndexUtils.copyFile(IndexUtils.java:63)
        at org.apache.maven.index.context.IndexUtils.copyDirectory(IndexUtils.java:56)
        at org.apache.maven.index.DefaultNexusIndexer.scan(DefaultNexusIndexer.java:291)
        ... 4 more

Removing ./index/nexus-maven-repository-index-packer.properties allows the subsequent run to succeed.

I encountered this when attempting to upgrade clojars.org from 4.1.2 to 7.1.6.