Re: [BUG] having 'plink' anywhere in the GIT_SSH environment variables sets putty = true

[Jeff King <peff@peff.net>]

On Wed, Apr 22, 2015 at 02:12:53PM -0500, Patrick Sharp wrote:

> Johannes,
> 
> You’re correct, looking back over it, I was pretty vague.
> 
> In truth, we are not using Windows OR putty at all.  Running git on an Ubuntu system, but we are setting the GIT_SSH environment variable to point to a shell script to use.
> 
> Upon attempting to run git ls-remote, the system was spitting out getaddrinfo errors for ‘atch’ .
> 
> Setting GIT_TRACE=2 showed that -batch was being added to the git command.
> 
> This was seen on several different servers with git versions 1.8.5.2, 1.9.1 and 2.3.5
> 
> After a bit we realized that it was the string ‘uplink’ in the GIT_SSH variable that was linked to the extra -batch flag.
> 
> Finally, after searching the git source, we narrowed it down to the ‘plink’ portion of the string.
> 
> https://github.com/git/git/blob/7c597ef345aed345576de616c51f27e6f4b342b3/connect.c#L747-L756

I think you want something like:

diff --git a/connect.c b/connect.c
index 9ae991a..58aad56 100644
--- a/connect.c
+++ b/connect.c
@@ -568,7 +568,8 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
 	conn->argv = arg = xcalloc(7, sizeof(*arg));
 	if (protocol == PROTO_SSH) {
 		const char *ssh = getenv("GIT_SSH");
-		int putty = ssh && strcasestr(ssh, "plink");
+		int putty = ssh && (ends_with(ssh, "plink") ||
+				    ends_with("plink.exe"));
 		if (!ssh) ssh = "ssh";
 
 		*arg++ = ssh;

though that is not quite enough (we do not have a case-insensitive
version of "ends_with"). I'm also not sure if matching just "plink" and
"plink.exe" at the end of the string is enough (I'm just guessing that
was the original reason for using strstr in the first place).

Note that I don't think just switching the strcasestr to look for
"plink.exe" is right. For one thing, it just punts on the problem (it
can still happen, it's just less likely to trigger). But for another,
you can have plink (without ".exe") on Linux systems.

-Peff