BUG Report: v12.0.0 "git difftool -d" fails with "fatal: cannot create directory at '': No such file or directory"

BUG Report: v12.0.0 "git difftool -d" fails with "fatal: cannot create directory at '': No such file or directory"

[Mark Phillips]

I am building git from source using gcc 4.8.5 on 64 bit linux.

I am sorry the log info is not very helpful, please tell me how to get more information about what is going wrong and I will collect the info for you!


V2.12.0 Broken log
==============

Export GIT_TRACE=1
git difftool -d HEAD~ 
09:11:27.797674 git.c:371               trace: built-in: git 'difftool' '-d' 'HEAD~'
09:11:27.798255 run-command.c:369       trace: run_command: 'diff' '--raw' '--no-abbrev' '-z' 'HEAD~'
09:11:27.798484 exec_cmd.c:118          trace: exec: 'git' 'diff' '--raw' '--no-abbrev' '-z' 'HEAD~'
09:11:27.800156 git.c:371               trace: built-in: git 'diff' '--raw' '--no-abbrev' '-z' 'HEAD~'
fatal: cannot create directory at '': No such file or directory
	

Running make check gives
fixed   0
success 14475
failed  0
broken  184
total   14804


Also broken in v2.12.0-rc0, v2.12.0-rc1 and v2.12.0-rc2
-----------------------------------------------------------------

V 2.11.1 works
===========

Re: BUG Report: v12.0.0 "git difftool -d" fails with "fatal: cannot create directory at '': No such file or directory"

[Johannes Schindelin]

Hi Mark,

On Thu, 2 Mar 2017, Mark Phillips wrote:

> I am building git from source using gcc 4.8.5 on 64 bit linux.
> 
> I am sorry the log info is not very helpful, please tell me how to get
> more information about what is going wrong and I will collect the info
> for you!

Well, you could provide a Minimal, Complete and Verifiable Example
(http://stackoverflow.com/help/mcve): most likely, the error depends on
particular features of your current HEAD, or environment variables.
Because i do *not* get that error if I run `git difftool -d HEAD~`.

So it is not so much about collecting info as about distilling your use
case into an example that allows other developers to reproduce the
problem, and subsequently fix it.

Ciao,
Johannes