Library Cannot Parse JSON File It Wrote

[JohnFayGeezer]

Description

I used the JSON library to "pretty-print" a JSON file. I then read that JSON file into a character array variable and the parser terminated on error. This has happened with several JSON files; I am submitting a minimal example.

Reproduction steps

I created the following file named "minimal.json" using Notepad++ on Windows. It contains four lines, including a blank last line:

{
"LABEL": 0.0
}

I then wrote the attached C++ program and built it using Cygwin.

g++ -g -DLINUX -Ijson/single_include json_test.cpp

I ran the executable with no command line inputs so that it read "minimal.json" and wrote "min_output.json". I then renamed "min_output.json" to "minimal_BadChar.json" and ran the program again, this time with a command line argument so that it read this file. The parser terminated on error with a message about an invalid input.

minimal.json
minimal_badChar.json
json_test.cpp.txt

Expected vs. actual results

I would expect the code to be able to read a file that it wrote.

Minimal code example

See files attached earlier.

Error messages

terminate called after throwing an instance of 'nlohmann::json_abi_v3_11_3::detail::parse_error'
  what():  [json.exception.parse_error.101] parse error at line 4, column 1: syntax error while parsing value - invalid literal; last read: '0.0<U+000A>}<U+000A>'; expected end of input

Compiler and operating system

Cyrwin g++ 11.3.0

Library version

3.11.3

Validation

• The bug also occurs if the latest version from the develop branch is used.
• I can successfully compile and run the unit tests.

[gregmarr]

Looks like you wrote the string in ASCII mode so it was written with newlines as \r\n and then read it in binary mode, so the \r was kept.