Bug report

Bug description:

With any JSON Lines file, such as:

❯ cat input.jsonl
{"ingredients":["frog", "water", "chocolate", "glucose"]}
{"ingredients":["chocolate","steel bolts"]}

This works on Python 3.12:

❯ python3.12 --version
Python 3.12.10
❯ python3.12 -m json.tool --json-lines input.jsonl
{
    "ingredients": [
        "frog",
        "water",
        "chocolate",
        "glucose"
    ]
}
{
    "ingredients": [
        "chocolate",
        "steel bolts"
    ]
}

But not 3.13 or higher:

❯ python3.13 --version
Python 3.13.3
❯ python3.13 -m json.tool --json-lines input.jsonl
I/O operation on closed file.
❯ python3.14 --version
Python 3.14.0a7
❯ python3.14 -m json.tool --json-lines input.jsonl
I/O operation on closed file.
❯ ./python.exe --version --version
Python 3.14.0a7+ (heads/main:e42bda94411, Apr 17 2025, 14:59:38) [Clang 16.0.0 (clang-1600.0.26.6)]
❯ ./python.exe Lib/test/test_json/test_tool.py -h
❯ ./python.exe -m json.tool --json-lines input.jsonl
I/O operation on closed file.

Bug report

Bug description:

CPython versions tested on:

Operating systems tested on:

Linked PRs