From 55944577d438af98fa8fb23f9a0e195a7eed1f2a Mon Sep 17 00:00:00 2001
From: Robert Hill <robert.hill@uphillsolutions.tech>
Date: Thu, 10 Sep 2026 22:16:32 -0400
Subject: [PATCH] fix(ssh): refuse a forced tty where sftp and captured output
 run

RequestTTY force in ssh_config closes the sftp channel, so the mount fails
with "remote host has disconnected", and a tty would also put carriage
returns in the remote-home output. Interactive paths still get their tty.
---
 lua/sshfs/lib/ssh.lua         |  6 +++++-
 tests/remote_command_spec.lua | 20 ++++++++++++++++++++
 tests/ssh_spec.lua            |  2 +-
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/lua/sshfs/lib/ssh.lua b/lua/sshfs/lib/ssh.lua
index 9bd27cc..6fc50fe 100644
--- a/lua/sshfs/lib/ssh.lua
+++ b/lua/sshfs/lib/ssh.lua
@@ -50,7 +50,11 @@ local function get_ssh_options(auth_type)
 
   -- A config RemoteCommand cannot coexist with the command these paths append,
   -- and sftp needs a plain session, so it is cleared for everything but a shell.
-  if auth_type == "batch" or auth_type == "socket" then table.insert(options, "RemoteCommand=none") end
+  if auth_type == "batch" or auth_type == "socket" then
+    table.insert(options, "RemoteCommand=none")
+    -- A forced tty closes the sftp channel and puts carriage returns in captured output.
+    table.insert(options, "RequestTTY=no")
+  end
 
   -- Add ControlMaster options
   local control_opts = Config.get_control_master_options()
diff --git a/tests/remote_command_spec.lua b/tests/remote_command_spec.lua
index 7eb408d..62df5c3 100644
--- a/tests/remote_command_spec.lua
+++ b/tests/remote_command_spec.lua
@@ -23,6 +23,26 @@ local function clears_remote_command(cmd)
   return option_index(cmd, "RemoteCommand=none") ~= nil
 end
 
+describe("RequestTTY handling", function()
+  it("refuses a forced tty on the paths that carry sftp or captured output", function()
+    local Ssh = load_ssh()
+
+    expect.truthy(option_index(Ssh.build_batch_command("example.com"), "RequestTTY=no"))
+    expect.truthy(option_index(Ssh.build_home_command("example.com"), "RequestTTY=no"), "readlink output must be clean")
+    expect.contains(Ssh.build_command_string("socket"), "-o RequestTTY=no")
+  end)
+
+  it("leaves the interactive authentication terminal a tty", function()
+    local Ssh = load_ssh()
+    expect.is_nil(option_index(Ssh.build_auth_command("example.com"), "RequestTTY=no"), "a password prompt needs one")
+  end)
+
+  it("leaves a terminal session a tty", function()
+    local Ssh = load_ssh()
+    expect.is_nil(option_index(Ssh.build_command("example.com", "/srv/app"), "RequestTTY=no"))
+  end)
+end)
+
 describe("RemoteCommand handling", function()
   it("clears it on every command that appends a remote command", function()
     local Ssh = load_ssh()
diff --git a/tests/ssh_spec.lua b/tests/ssh_spec.lua
index 68bcc4f..ab346a9 100644
--- a/tests/ssh_spec.lua
+++ b/tests/ssh_spec.lua
@@ -13,7 +13,7 @@ end
 describe("Ssh.build_command_string", function()
   it("passes the control path and clears any RemoteCommand when reusing a socket", function()
     local Ssh = load_ssh()
-    expect.eq(Ssh.build_command_string("socket"), "ssh -o RemoteCommand=none -o " .. CONTROL_PATH)
+    expect.eq(Ssh.build_command_string("socket"), "ssh -o RemoteCommand=none -o RequestTTY=no -o " .. CONTROL_PATH)
   end)
 
   it("forces a master and disables prompts for batch connections", function()