--line-ranges formats entire file when ranges are at EOF

[jvacek]

Line ranges seem to format an entire file when the range goes to the end of the file

microsoft/vscode-black-formatter#472

• Take a file that is unformatted
• Set the line ranges to any portion as long as the last line is EOF
• The entire file is formatted

For example, take this code:

** Ensure empty last line **

abc = 'def'
ghi= 'jkl'
mno='pqr'
stu='vwx'

And run it with these arguments:

black --line-ranges 4-5 file.py

The resulting error is:

> cannot format file.py: INTERNAL ERROR: ...

Expected behavior

Only stu='vwx' being formatted, and not lines 1-3

Environment

• Black's version: 24.2.0
• OS and Python version: MacOS 14.3.1, Python 3.10.3

Additional context

[RedGuy12]

From my tests, the line range only fails when the range ends on the last line and the last line is empty

[jvacek]

That won't play well for anyone who enforces an empty last line, and has their IDE send the line ranges to black.