Incorrect block allocation in transferFrom implementation

[fred01]

I have a simple test that creates a file and fills it by the transferFrom method.

    @Test
    fun testBlockSizeFit() {
        val blockSize = 4096L
        val fs = Jimfs.newFileSystem(
            Configuration.unix().toBuilder()
                .setBlockSize(4096)
                .setMaxSize(blockSize*2)
                .build())
        val tmpDir = fs.getPath("/tmp/").also { Files.createDirectory(it) }
        val tmpFile = Files.createTempFile(tmpDir, "file", ".tmp")
        val data = Random.nextBytes(blockSize.toInt())
        assertThat(data.size.toLong()).isEqualTo(blockSize) // ensure data size is correct
        val fileChannel = FileChannel.open(tmpFile, StandardOpenOption.CREATE, StandardOpenOption.WRITE)
        fileChannel.use {
            it.transferFrom(Channels.newChannel(ByteArrayInputStream(data)), 0, Long.MAX_VALUE)
        }
        assertThat(tmpDir.fileStore().usableSpace).isEqualTo(blockSize)
    }

This test fails on the assertion with the following values:

expected:<[4096]L> but was:<[0]L>
Expected :[4096]L
Actual   :[0]L

But the test passes if I pass 4096 instead of Long.MAX_VALUE as the value of limit parameter of the transferFrom method.
It seems, transferFrom doesn't respect the actual size of the source channel and allocates extra block when copying.

[cgdecker]

Thanks for the report. I caught a few other issues with transferTo while I was fixing it.

[fred01]

Wow! Thanks for quick fix, that's awesome!

[cpovirk]

And as of 1.3.0 (now on Maven Central), the fix is actually released.