src/tool_parsecfg.c:288 -- free(pathalloc) is not required in parseconfig()

[bxac]

I did this

mkdir build_x64_shared
cd build_x64_shared
cmake -G "Visual Studio 16 2019" -A x64 .. -DCMAKE_USE_WINSSL=ON -DCURL_WINDOWS_SSPI=ON -DCURL_STATICLIB=OFF -DCURL_STATIC_CRT=ON -DBUILD_SHARED_LIBS=ON -DBUILD_TESTING=OFF ..
cmake --build . --config Debug -- /m

I expected the following

Expecting working curl.exe, but it fires debug assertion in debug_heap.cpp:996 ( _ASSERTE(__acrt_first_block == header); )

curl/libcurl version

curl 7.68.0-DEV (Windows) libcurl/7.68.0-DEV Schannel
Release-Date: [unreleased]
Protocols: dict file ftp ftps gopher http https imap imaps ldap pop3 pop3s rtsp smtp smtps telnet tftp
Features: AsynchDNS IPv6 Kerberos Largefile NTLM SPNEGO SSL SSPI

operating system

Microsoft Windows [Version 10.0.18362.535]

[dfandrich]

What command-line causes this?

[bagder]

(and the free() is obviously needed, as otherwise that function would leak that memory)

[bxac]

What command-line causes this?

Just "curl.exe" w/o parameters.

(and the free() is obviously needed, as otherwise that function would leak that memory)

Seems "pathalloc" isn't allocated from heap at this point.

[bagder]

Seems "pathalloc" isn't allocated from heap at this point.

If it isn't, then it is NULL, right? Because if you can get it to be non-NULL and not allocated then I'm curious how!

[bxac]

No, it is not NULL (checked in VS debugger).

Because if you can get it to be non-NULL and not allocated then I'm curious how!

I'm curious too. That's why I've created this issue instead of pull-request with fix.

[bagder]

If you run it in the debugger, how about setting a break-point on the first line of the function and just single-step until that free() and see where it gets assigned? It seems likely to be a call to curl_maprintf() ...

[bxac]

where it gets assigned? It seems likely to be a call to curl_maprintf() ...

Yes, in line
pathalloc = curl_maprintf("%s%s%ccurlrc", home, DIR_CHAR, prefix);

And if I add
free(pathalloc);
after that line, I got assert there.

But free(home) works without assert.

[bagder]

Ah, it should be a curl_free() !

[bagder]

Will work on the fix in #4731