Re: [PATCH v2 2/2] connect: improve check for plink to reduce false positives

> (I'm not sute if the commit message describes the problem deep enough
> for readers which are not familar with all the details of the original
> report):
> A feature implemented for Windows may break things for e.g. Linux users)
> The following may read exaggerated, so please read it as a suggestion.
> 
> The git_connect function has code to handle plink and tortoiseplink
> specially, as they require different command line arguments compared to
> OpenSSH (-P instead of -p, tortoiseplink uses -batch), commit 36ad53ffee6ed.
> The special handling is only needed for Windows, and a sloppy
> case-insensitve search for "plink" will trigger that an the extra
> parameter "-batch" is added to the command line.
> 
> This was observed on a Linux system where a command line including
> "/uplink_deploy/" was used.
> 
> There are different ways to improve the situation:
> (The following mentions only plink, but assumes that tortoiseplink is handled
>  similar)
> a) Disable the plink/tortoiseplink special handling on non-Windows systems
> b) Tighten the search for plink:
>    Allow basename() == plink || !!strcasestr(ssh, "plink.exe")
> c) Tighten the search for plink:
>    Allow basename() == plink || !!strcasestr(ssh, "plink.exe")
> d) Tighten the check for tortoiseplink.
>    Today we set "int putty" to true when plink is found, and -batch
>    is set when tortoiseplink is not found.
>    This fixes the reported bug, but still has the -P problem.
> e) Unix users typically use shell scripts and could use GIT_SSH_COMMAND.
>    Declare the GIT_SSH as not-well-documented (and to obsolete ?) for non-Windows systems,
> 
> This patch implements c):
> Extract the basename and compare it to plink, plink.exe respective
> tortoiseplink/tortoiseplink.exe
> 
> Note that there is a slight risk of breakage for Windows users:
> Strings like "myplink" or "plink-0.83" are no longer accepted.

> -------------
> What about adding test-cases in t5601,
> this will ease the documentation later.
> f:/util/plink
> /c/util/plink.exe
> f:/util/tortoiseplink
> /c/util/tortoiseplink.exe
> /usr/local/uplink/sshwrapper.sh