Uncaught exception in builtins.toJSON

[NaN-git]

Describe the bug

builtins.toJSON throws an exception, when an input string is not a valid UTF-8 string, e.g.

error: [json.exception.type_error.316] invalid UTF-8 byte at index 308: 0xF7

nix repl quits (crashes?).

Steps To Reproduce

1. Download test file:

wget -O - https://github.com/flenniken/utf8tests/raw/refs/heads/main/utf8tests.bin | head -n 208 > utf8tests.bin

2. Evaluate the following Nix expression, e.g. in nix repl:

builtins.toJSON (builtins.readFile ./utf8tests.bin)

Expected behavior

Catch exception and display proper error message.

Or it should be enforced that the file read by builtins.readFile is UTF-8 encoded because these issues propagate to other parts of Nix and Nix assumes implicitly that strings are UTF-8 encoded.

Checklist

• checked latest Nix manual (source)
• checked open bug issues and pull requests for possible duplicates

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