python36 @3.6.2: aborts when importing struct; unallocated pointer being freed

[jhelm (John Helm)]

Loading struct works with Python35 but crashes Python36. Thanks. /John Helm

Python 3.6.2 (default, Jul 18 2017, 14:13:41)
[GCC 4.2.1 Compatible Apple LLVM 7.3.0 (clang-703.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
Python(15382,0x7fff7f851000) malloc: *** error for object 0x10f8b5110: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6
jlh-MacBook-Pro:fbaNG01 jlh$

[jhelm (John Helm)]

Correcting formatting of code block.

jlh-MacBook-Pro:fbaNG01 jlh$ python
Python 3.6.2 (default, Jul 18 2017, 14:13:41)
[GCC 4.2.1 Compatible Apple LLVM 7.3.0 (clang-703.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
Python(15382,0x7fff7f851000) malloc: *** error for object 0x10f8b5110: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6
jlh-MacBook-Pro:fbaNG01 jlh$

[mf2k (Frank Schima)]

FYI, it works fine on my computer.

[mf2k (Frank Schima)]

What version of MacOS are you running?

[jhelm (John Helm)]

Ouch. OS X 10.11.6 (El Capitan); and while I'm at it, Xcode is version is Version 8.0 (8A218a). Should I remove and reinstall MacPorts? Thanks /John

[mf2k (Frank Schima)]

According to the wiki wiki:XcodeVersionInfo#OSX10.11, you should upgrade your Xcode and command line tools to 8.2.1. Then you can try re-installing your ports (no need to re-install Macports itself).

[jhelm (John Helm)]

Thank you Frank. I upgraded to xcode 8.2.1 (8C1002) and verified the compiler version to be

jlh-MacBook-Pro:fbaNG01 jlh$ cc --version
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin15.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

I uninstalled and reinstalled python36, ran 'port diagnose', and then ran 'sudo port -nR upgrade --force python36' to force a rebuild. I still get the error.

Could my path or environment be wrong? Here's echo $PATH

/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/MacGPG2/bin:/Applications/Postgres.app/Contents/Versions/latest/bin

I won't spam you with the environment, but I can see anything egregious.

Finally I've installed python34, python33, and python31; they all import struct successfully.

[mf2k (Frank Schima)]

While the path is largely irrelevant, it can effect if you are running Macports python 3.6 when you type "python" from the command line. It does look like you are running Macports python 3.6. However, it is slightly sub-optimal and should probably be optimized to remove the redundant path "/usr/local/bin", which is showing up twice.

It might be an underlying dependency of python 3.6 that needs to be rebuilt. Although I think they are same as the older pythons and you say those work. Shrug.

[ryandesign (Ryan Carsten Schmidt)]

I can reproduce this problem on Sierra.

$ python3.5
Python 3.5.4 (default, Aug 14 2017, 18:26:29) 
[GCC 4.2.1 Compatible Apple LLVM 8.1.0 (clang-802.0.42)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
>>> ^D
$ python3.6
Python 3.6.2 (default, Jul 23 2017, 12:22:19) 
[GCC 4.2.1 Compatible Apple LLVM 8.1.0 (clang-802.0.42)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
Python(88518,0x7fffa4f9f3c0) malloc: *** error for object 0x1047ff110: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6

[jmroot (Joshua Root)]

Is this still a problem with the current version? I can't reproduce it.

[jmroot (Joshua Root)]

Closing as per email from reporter.