Occur error when parse character '\'

[AronZhi]

Description

When I run code as follows:

    std::string sData("{\"a\":\"b\\a\",\"b\":2}");
    nlohmann::json obj = nlohmann::json::parse(sData);

It both throw error in version 3.7.3 and 3.11.2.

After delete '' as follows:

    std::string sData("{\"a\":\"ba\",\"b\":2}");
    nlohmann::json obj = nlohmann::json::parse(sData);

It will run successfuly.

Reproduction steps

Run code as follows:

    std::string sData("{\"a\":\"b\\a\",\"b\":2}");
    nlohmann::json obj = nlohmann::json::parse(sData);

It both throw error in version 3.7.3 and 3.11.2.

Expected vs. actual results

expect:
json::parse run success and no error occur.

actually:
error occur

Minimal code example

No response

Error messages

No response

Compiler and operating system

Microsoft Visual C++ 2019 / Build Tools 16.3.1+1def00d3d (and possibly later)

Library version

3.11.2 or 3.7.3

Validation

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

[nlohmann]

The exception message should tell you that backslashes need to be escaped.

[AronZhi]

The code in reproduction steps section, I did escaped the backslashes, but Git don't show the original code.

[AronZhi]

When processing a string containing a windows format path, an unhandled exception will be thrown

[AronZhi]

This issue is same as issue #2652

[gregmarr]

@AronZhi See here for instructions on how to format code so it's not mangled: https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/creating-and-highlighting-code-blocks