Potential unreachable condition in FileInfo.moveToNewLocation #4736

BUG REPORT

Describe the bug

While analyzing the implementation of FileInfo.moveToNewLocation, I noticed a condition that appears to be unreachable.

Specifically, the following check:

if (written <= 0 && size > 0)

seems redundant given the logic of the preceding loop.

To Reproduce

This is not a runtime bug but a logical issue identified through static analysis.

Relevant code:

long written = 0;
while (written < size) {
    long count = fc.transferTo(written, size, newFc);
    if (count <= 0) {
        throw new IOException("Copying to new location " + rlocFile + " failed");
    }
    written += count;
}

Expected behavior

The condition after the loop should represent a reachable state.

However, based on the current logic:

• If size > 0, the loop executes at least once.
• If count <= 0, an exception is thrown immediately.
• Otherwise, written is incremented (written += count, with count > 0).

Therefore, after normal loop termination, written should always be greater than 0.

Screenshots

Not applicable.

Additional context

Given the loop semantics, the condition:

if (written <= 0 && size > 0)

appears to be unreachable.

This might be:

• a leftover defensive check, or
• redundant code that could be removed for clarity.

cc @gulyx