files.block is not working as expected when path exists and line missing

[xiaoxiaoyu93]

files.block is not working as expected

Describe the bug

The document (both 2x and next) says:

Content appended if line not found in the file
If content is not in the file but is required (present=True) and line is not found in the file, content (surrounded by markers) will be appended to the file. The file is created if necessary.

But in the case of the actual empty file, there is no addition.

To Reproduce

Steps to reproduce the behavior, please include where possible:

from pyinfra.operations import files

files.block(
    name="Block Test",
    path="test.txt",
    line="foo",
    content="bar",
    present=True,
    after=True,
)

$ rm test.txt
$ touch test.txt
$ pyinfra @local test.py

$ cat test.txt #just empty line

Expected behavior

$ cat test.txt
# BEGIN PYINFRA BLOCK
bar
# END PYINFRA BLOCK

Meta

• Include output of pyinfra --support.

    If you are having issues with pyinfra or wish to make feature requests, please
    check out the GitHub issues at https://github.com/Fizzadar/pyinfra/issues .
    When adding an issue, be sure to include the following:

    System: Darwin
      Platform: macOS-14.0-x86_64-i386-64bit
      Release: 23.0.0
      Machine: x86_64
    pyinfra: v3.0b0
    Executable: /Users/who/OneClick/LunaticDaemon/.venv/bin/pyinfra
    Python: 3.11.7 (CPython, Clang 15.0.0 (clang-1500.1.0.2.5))

• How was pyinfra installed (source/pip)?
  pip
• Include pyinfra-debug.log (if one was created)
  None
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