Hard-fault in RollingFileAppender

kamocat commented 4 years ago

All for formatters work fine with the SerialAppender, but when I use the RollingFileAppender I run into trouble.

I'm finding that these MARK statements don't go quite fine-grained enough for this problem. A hardware debugger would be invaluable.

prototypicalpro commented 4 years ago

I don't have an SDcard Feather yet, but I'll be able to debug it Friday. In the meantime, a few things I noticed:

The problem probably has something to do with constructing a String using a char* here: https://github.com/kamocat/plog/blob/07716e54da138f9b6f6dd985d94d12d4d38cd002/include/plog/Formatters/MessageOnlyFormatter.h#L17 Though the String constructor should only be called after getMessage completes, I still suspect this is the issue.
Your casting in getMessage may also be causing issues. The static_cast<util::nostringstream> constructs a new util::nostringstream using m_message as the constructor parameter, which may or may not lead to dangling pointers (util::nostringstream may decide to make a copy, or may not). What might work better is a const_cast on this, which just cheats away the const qualifier on m_message:
```
virtual const util::nchar* getMessage() const 
{MARK; 
 return static_cast<const util::nchar*>( 
     const_cast<Record*>(this)->m_message.buf()
 ); 
}
```

kamocat commented 4 years ago

I'll let you deal with this one. I made a simpler file appender - it works well enough for me.

prototypicalpro commented 4 years ago

I opened a pull request to fix the second point, and I'll look into the hardfault.

prototypicalpro commented 4 years ago

I found one issue. You construct a obufstream here with no pointer to stream into: https://github.com/kamocat/plog/blob/a5d6fb133aafc2ec5fd309590c1d9339c4c8e5ce/include/plog/Appenders/RollingFileAppender.h#L86-L89 Without a parameter, obufstream defaults to a null pointer that can be changed later with obufstream::init. Since you do not change this value, the code immediately hard faults after dereferencing the null pointer.

kamocat commented 4 years ago

Thanks for finding that! I searched the rest of the library, and this appears to be the only improperly initialized nostringstream.

kamocat / plog