Merge branch 'bc/connect-plink' into maint

The connection initiation code for "ssh" transport tried to absorb
differences between the stock "ssh" and Putty-supplied "plink" and
its derivatives, but the logic to tell that we are using "plink"
variants were too loose and falsely triggered when "plink" appeared
anywhere in the path (e.g. "/home/me/bin/uplink/ssh").

* bc/connect-plink:
  connect: improve check for plink to reduce false positives
  t5601: fix quotation error leading to skipped tests
  connect: simplify SSH connection code path

connect.c

@@ -724,7 +724,7 @@ struct child_process *git_connect(int fd[2], const char *url,
 		conn->in = conn->out = -1;
 		if (protocol == PROTO_SSH) {
 			const char *ssh;
-			int putty;
+			int putty, tortoiseplink = 0;
 			char *ssh_host = hostandport;
 			const char *port = NULL;
 			get_host_and_port(&ssh_host, &port);
@@ -743,28 +743,40 @@ struct child_process *git_connect(int fd[2], const char *url,
 				free(path);
 				free(conn);
 				return NULL;
-			} else {
-				ssh = getenv("GIT_SSH_COMMAND");
-				if (ssh) {
-					conn->use_shell = 1;
-					putty = 0;
-				} else {
-					ssh = getenv("GIT_SSH");
-					if (!ssh)
-						ssh = "ssh";
-					putty = !!strcasestr(ssh, "plink");
-				}
-
-				argv_array_push(&conn->args, ssh);
-				if (putty && !strcasestr(ssh, "tortoiseplink"))
-					argv_array_push(&conn->args, "-batch");
-				if (port) {
-					/* P is for PuTTY, p is for OpenSSH */
-					argv_array_push(&conn->args, putty ? "-P" : "-p");
-					argv_array_push(&conn->args, port);
-				}
-				argv_array_push(&conn->args, ssh_host);
 			}
+
+			ssh = getenv("GIT_SSH_COMMAND");
+			if (ssh) {
+				conn->use_shell = 1;
+				putty = 0;
+			} else {
+				const char *base;
+				char *ssh_dup;
+
+				ssh = getenv("GIT_SSH");
+				if (!ssh)
+					ssh = "ssh";
+
+				ssh_dup = xstrdup(ssh);
+				base = basename(ssh_dup);
+
+				tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
+					!strcasecmp(base, "tortoiseplink.exe");
+				putty = !strcasecmp(base, "plink") ||
+					!strcasecmp(base, "plink.exe") || tortoiseplink;
+
+				free(ssh_dup);
+			}
+
+			argv_array_push(&conn->args, ssh);
+			if (tortoiseplink)
+				argv_array_push(&conn->args, "-batch");
+			if (port) {
+				/* P is for PuTTY, p is for OpenSSH */
+				argv_array_push(&conn->args, putty ? "-P" : "-p");
+				argv_array_push(&conn->args, port);
+			}
+			argv_array_push(&conn->args, ssh_host);
 		} else {
 			/* remove repo-local variables from the environment */
 			conn->env = local_repo_env;

t/t5601-clone.sh

@@ -296,6 +296,12 @@ setup_ssh_wrapper () {
 	'
 }
 
+copy_ssh_wrapper_as () {
+	cp "$TRASH_DIRECTORY/ssh-wrapper" "$1" &&
+	GIT_SSH="$1" &&
+	export GIT_SSH
+}
+
 expect_ssh () {
 	test_when_finished '
 		(cd "$TRASH_DIRECTORY" && rm -f ssh-expect && >ssh-output)
@@ -332,9 +338,36 @@ test_expect_success !MINGW,!CYGWIN 'clone local path foo:bar' '
 
 test_expect_success 'bracketed hostnames are still ssh' '
 	git clone "[myhost:123]:src" ssh-bracket-clone &&
-	expect_ssh myhost '-p 123' src
+	expect_ssh "-p 123" myhost src
 '
 
+test_expect_success 'uplink is not treated as putty' '
+	copy_ssh_wrapper_as "$TRASH_DIRECTORY/uplink" &&
+	git clone "[myhost:123]:src" ssh-bracket-clone-uplink &&
+	expect_ssh "-p 123" myhost src
+'
+
+test_expect_success 'plink is treated specially (as putty)' '
+	copy_ssh_wrapper_as "$TRASH_DIRECTORY/plink" &&
+	git clone "[myhost:123]:src" ssh-bracket-clone-plink-0 &&
+	expect_ssh "-P 123" myhost src
+'
+
+test_expect_success 'plink.exe is treated specially (as putty)' '
+	copy_ssh_wrapper_as "$TRASH_DIRECTORY/plink.exe" &&
+	git clone "[myhost:123]:src" ssh-bracket-clone-plink-1 &&
+	expect_ssh "-P 123" myhost src
+'
+
+test_expect_success 'tortoiseplink is like putty, with extra arguments' '
+	copy_ssh_wrapper_as "$TRASH_DIRECTORY/tortoiseplink" &&
+	git clone "[myhost:123]:src" ssh-bracket-clone-plink-2 &&
+	expect_ssh "-batch -P 123" myhost src
+'
+
+# Reset the GIT_SSH environment variable for clone tests.
+setup_ssh_wrapper
+
 counter=0
 # $1 url
 # $2 none|host