Description

When you try to load a file that doesn't exist (using std::ifstream), InputType will be null and from what I saw, this isn't checked anywhere. I suppose this should be checked inside input_adapter function:

this issue doesn't occur when std::FILE* is used, because:

we have condition to check file pointer inside input_adapter for std::FILE*

Reproduction steps

1. Use code from tutorial (https://fktn-k.github.io/fkYAML/tutorials/#__tabbed_1_2)
2. Make sure file doesn't exist
3. Compile and test = infinity loop because stream is empty

Expected vs. actual results

Expected result is throw fkyaml::exception, currently we have infinity loop

Minimal code example

No response

Error messages

No response

Compiler and operating system

Windows: C++latest, MSVC latest

Library version

0.3.9/0.3.10

Validation

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